Langert v. Secretary of Health and Human Services

                 In the United States Court of Federal Claims
                                   OFFICE OF SPECIAL MASTERS
                                           No. 22-809V

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                            *
MELISS LANGERT,             *                                          Chief Special Master Corcoran
                            *
                Petitioner, *                                          Filed: June 13, 2025
                            *
          v.                *
                            *
SECRETARY OF HEALTH         *
AND HUMAN SERVICES,         *
                            *
                Respondent. *
                            *
*************************

Leah V. Durant, Law Offices of Leah V. Durant, Washington, DC, for Petitioner.

Ryan D. Pyles, U.S. Department of Justice, Washington, DC, Respondent.

                                      ENTITLEMENT DECISION 1

        On July 26, 2022, Meliss Langert filed a petition seeking compensation under the National
Vaccine Injury Compensation Program (the “Vaccine Program). 2 Petitioner alleges that she
suffered Guillain-Barré syndrome (“GBS”) as a result of receiving the tetanus-diphtheria-
acellular-pertussis (“Tdap”) vaccine on September 4, 2019. Petition (ECF No. 1) at 1.

        I determined that this matter could be fairly resolved via ruling on the record, and both
sides filed briefs in support of their positions. Petitioner’s Brief, filed Aug. 9, 2024 (ECF No. 41)
(“Br.”); Respondent’s Opposition, filed Oct. 31, 2024 (ECF No. 47) (“Opp.”); Petitioner’s Reply,
filed Jan. 13, 2025 (ECF No. 49). The matter is now ripe for resolution. For the reasons set forth

1
  Under Vaccine Rule 18(b), each party has fourteen (14) days within which to request redaction “of any information
furnished by that party: (1) that is a trade secret or commercial or financial in substance and is privileged or
confidential; or (2) that includes medical files or similar files, the disclosure of which would constitute a clearly
unwarranted invasion of privacy.” Vaccine Rule 18(b). Otherwise, the whole Decision will be available to the public
in its present form. Id.


2
  The Vaccine Program comprises Part 2 of the Childhood Vaccine Injury Act of 1986, Pub. L. No. 99-660, 100 Stat.
3758, codified as amended at 42 U.S.C. §§ 300aa-10 through 34 (2012) (“Vaccine Act” or “the Act”). Individual
section references hereafter will be to § 300aa of the Act (but will omit that statutory prefix).
in more detail below, I hereby deny entitlement. Petitioner has not preponderantly established that
her GBS (assuming it could be caused by the Tdap vaccine) began in a medically-acceptable
timeframe, when measured from the date of vaccination.

I.      Factual Background

        Petitioner’s pre-vaccination medical history includes several years of treatment for severe
chronic low back pain, resulting in spinal and back procedures. Ex. 12 at 12; Ex. 7 at 21, Ex. 10 at
48–50. In fact, she previously complained of leg numbness and tingling that arguably was a
product of such issues. Ex. 7 at 21. Much of this treatment, however, occurred nearly three years
prior to the vaccination at issue—making it difficult to associate it with what transpired in the post-
vaccination timeframe. Otherwise, the filed medical records establish persistent concerns with a
likely sinus infection in the summer of 2019. Ex. 11 at 70, 72.

        Vaccination and Initial Symptoms

        On September 4, 2019, Ms. Langert received a Tdap vaccine during an urgent care visit
following a dog bite. Ex. 1 at 1–2. The next day (September 5th), she saw an optometrist, reporting
that a “few days ago [she] was on [the] phone for a few hours and awoke the next morning with
OD [right eye] ‘out of focus[;]’ improved with lifting upper eyelid, next day both eyes were out of
focus, no physical discomfort, bilateral temporal discomfort, improves with chin down.” Ex. 15 at
5. She was deemed to have likely experienced sudden-onset vertical diplopia 3 of both eyes, and an
MRI was proposed. Id. at 6.

       On September 6, 2019 (now two days post-vaccination), Petitioner went to a hospital
emergency department, reporting fatigue, myalgias, nausea, and dizziness with close-to-syncopal
episodes “[s]ince” her vaccination two days before. Ex. 12 at 11. Notes from this visit indicate that
Ms. Langert displayed “elevated sed[imentation] rate” (suggesting the presence of some degree of
inflammation), and that she attributed her condition to the Tdap vaccine, but her exam revealed no
obvious problems and she otherwise seemed well, so she was discharged that same day. Id. at 10–
11.

        In further follow-up to her concerns that the vaccination explained her symptoms,
Petitioner visited rheumatologist Ashima Malik, M.D., on September 9, 2019, reporting “aches
and pains after [T]dap injection,” and in particular back pain, which she stated had begun on
September 5th (or one day post-vaccination), and which she deemed to be severe. Ex. 28 at 73–74.
She also was at this time experiencing leg weakness but no numbness or tingling. Id. at 74.



3
 “Diplopia” is defined as “the perception of two images of a single object.” Diplopia, Dorland’s Medical Dictionary
Online, https://www.dorlandsonline.com/dorland/definition?id=14354&searchterm=diplopia (last visited June 13,
2025).

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        A physical exam performed at this time did not reveal notable strength/weakness deficits
in Petitioner’s limbs, and also resulted in normal reflexes. Ex. 28 at 77. Dr. Malik speculated that
Petitioner may have experienced a “severe post vaccine [side effect with] near
syncope/hypertension/dehydration and severe myalgia,” and proposed that Petitioner seek
emergency care again if she began to experience greater weakness of respiratory symptoms, since
these kinds of complications could provide evidence of “demyelinating disease and GBS like
syndrome[s] that are rare but can be seen [with] inactivated vaccine[s].” Id. at 79. (Petitioner also
around this time visited a spine and pain management treatment center she had previously utilized
for prior pain concerns, reporting that she had begun experiencing lower back pain the day after
vaccination (September 5, 2019) followed by lower extremity weakness, with pain radiating to her
legs and feet. Ex. 10 at 16).

         Emergency Treatment and Hospitalization

        Petitioner returned to the emergency department on September 11, 2019, reporting “all
over joint pain” and weakness after receipt of the Tdap vaccine. Ex. 12 at 68. She had difficulty
moving her right leg, but could “maintain position” in bed when the leg was passively flexed, and
did not display objective weakness when moved by a treater. Id. at 69. A lumbar MRI performed
at this time revealed evidence of slipped vertebrae but was largely otherwise normal, as was a
brain/ocular orbit MRI (except for some evidence of “chronic small vessel ischemic changes” and
pansinusitis 4). Ex. 17 at 9–11. Petitioner also went back to the spinal pain center the next day for
evaluation of her lower back pain. Ex. 10 at 10–14. There she received a diagnostic medial branch
nerve block 5 and was referred to neurology for an EMG. 6 Id. at 14.

       Petitioner’s symptoms continued to progress, however, and on September 13, 2019, she
was taken to the hospital by EMS personnel. Ex. 29 at 6. The records from this emergency
intervention note that Petitioner had reported post-vaccination “complications’ consistent with
what is discussed above, and that “this morning she began to notice weakness in her (L) leg, and
now she has almost no movement in both legs,” as well as more vision disturbances. Id.

4
  “Pansinusitis” is defined as “inflammation involving all of the paranasal sinuses on one side.” Pansinusitis, Dorland’s
Medical Dictionary Online, https://www.dorlandsonline.com/dorland/definition?id=36617&searchterm=pansinusitis
(last visited June 13, 2025).
5
  “Nerve Block” is a “regional anesthesia achieved by making extraneural or paraneural injections of anesthetics next
to the nerve whose conductivity is to be cut off.” Nerve Block, Dorland’s Medical Dictionary Online,
https://www.dorlandsonline.com/dorland/definition?id=60799&searchterm=nerve+block (last visited June 13, 2025).
6
  An electromyogram (“EMG”) is “an electrodiagnostic technique for recording the extracellular activity (action
potentials and evoked potentials) of skeletal muscles at rest, during voluntary contractions, and during electrical
stimulation; performed using any variety of surface of electrodes, needle electrodes, and devices for amplifying,
transmitting, and recording the signals.” Electromyography, Dorland’s Medical Dictionary Online,
https://www.dorlandsonline.com/dorland/definition?id=15854&searchterm=electromyography (last visited June 13,
2025).


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        Petitioner was thereafter hospitalized from September 13–19, 2019. The history section
from Petitioner’s initial treatment records note that she began reporting limb and hip pain
“[s]hortly after” her September 4th vaccination, and that her pain had resolved but she was still
experiencing weakness in her legs, double vision, and finger-tip tingling. Ex. 12 at 137. Petitioner
received IVIG 7 treatment during her hospitalization, which seemed to cause improvement, and she
was eventually discharged to acute in-patient rehabilitation. Id. at 164. Upon discharge, Petitioner
received a GBS diagnosis, and it was speculated that her vaccination was related. Id. at 162.

         Petitioner remained in rehab until mid-October 2019. Id. at 370. During this period, she
noted recurrence of double vision whenever she sat up, but was able to ambulate with a cane (for
at least short distances). Id. She subsequently had a follow-up visit with a neurologist in November
2019, by which point she was receiving physical therapy (“PT”). Ex. 14 at 15. Petitioner now
required use of a walker, and displayed right foot drop, plus more recent left side face numbness.
Id. However, her vision symptoms were again noted as having improved, and additional MRIs did
not reveal any concerning neurologic issues. Ex. 17 at 7.

        Additional records filed reflecting treatment Petitioner received into 2020 do not shed
much light on the likely cause of her neurologic illness. By January 2020, Petitioner was finding
increased strength in the wake of continued PT, although she was still experiencing right leg
weakness and some foot cramping. Ex. 14 at 32. An additional brain MRI performed in January
2020 revealed no new or concerning neurologic issues, although it was consistent with prior sinus-
related findings. Ex. 17 at 5–6. Petitioner was formally discharged from PT later that summer,
although she was still experiencing some balance issues plus fatigue and cramping/aching. Ex. 9
at 53–54.

        By August 2020, Petitioner continued to experience right leg cramping, as well as some
right-sided face numbness. Ex. 14 at 55. She was advised to start again with nerve pain medication
(which she had tapered off from earlier in the year) to alleviate the symptoms. Id. at 56. A CT scan
performed in November 2020 also confirmed the existence of chronic sinusitis which had
progressed over the last several years. Ex. 17 at 3.

II.     Expert Reports

        A.       Petitioner’s Expert — David M. Simpson, M.D.

       Dr. Simpson, a neurologist, offered three written reports in this matter. Report, dated Sept.
24, 2023, filed as Ex. 32 (ECF No. 34-1) (“Simpson First Rep.”); Report, dated Mar. 29, 2024,

7
  “Intravenous Immunoglobulin” is defined as “a pooled antibody, and a biological agent used to manage various
immunodeficiency states and a plethora of other conditions, including autoimmune, infectious, and inflammatory
states. The ultimate goal of this therapy is to normalize a compromised immune system.” Intravenous Immunoglobulin
(IVIG), National Library of Medicine, https://www.ncbi.nlm.nih.gov/books/NBK554446/ (last visited June 13, 2025).

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filed as Ex. 48 (ECF No. 36) (“Simpson Supp. Rep.”) Report, dated June 30, 2024, filed as Ex. 49
(ECF No. 40-1) (“Simpson Second Supp. Rep.”). Dr. Simpson opines that Ms. Langert was
properly diagnosed with GBS, and further maintains that the onset of her neurological symptoms
(beginning five days post-vaccination) is consistent with the medical literature for a vaccine-
induced GBS. Simpson First Rep. at 9.

       Dr. Simpson is a Professor of Neurology and the Director of the Neuromuscular Division
and Clinical Neurophysiology Laboratories at the Icahn School of Medicine at Mount Sinai, where
he has worked as an Attending Neurologist since 1984. See Curriculum Vitae, filed Sept. 29, 2023
(ECF No. 34-2) (“Simpson CV”) at 2. He received his medical degree from SUNY at Buffalo
School of Medicine and underwent residency and fellowship training at Cornell University
Medical Center and Massachusetts General Hospital. Id. at 1. He is certified by the National Board
of Medical Examiners, the American Board of Psychiatry and Neurology with subspecialties in
Clinical Neurophysiology and Neuromuscular Medicine, and the American Board of
Neuromuscular and Electrodiagnostic Medicine. Id. Dr. Simpson has published extensively, and
has given numerous presentations and lectures on the subject of neurological disorders, including
peripheral neuropathy. Id. at 3–95.

       First Report

         Before addressing his medical opinion in the matter, Dr. Simpson briefly summarized the
pertinent medical facts and circumstances. See generally Simpson First Rep. at 1–6. There are, he
explained, several biologic mechanisms by which a vaccine might lead to a neurologic illness—
molecular mimicry; neurotoxic effect; immune complex formation; and/or loss of self-tolerance—
adding further that “ample evidence” associates vaccination and a variety of demyelinating
neuropathies. Id. at 7; see also T. Safranek et al., Reassessment of the Association between
Guillain-Barré Syndrome and Receipt of Swine Influenza Vaccine in 1976-1977: Results of a Two-
State Study, 133 Am. J. Epidemiol. 940 (1991), filed as Ex. 35 (ECF No. 34-3) (“Safranek”)
(discussing the outbreak of GBS cases following the swine flu vaccine program in 1976); M.A.
Pou et al., Development of Autoimmune Diseases after Vaccination, 14 J. Clin. Rheumatol. 243
(2008), filed as Ex. 37 (ECF No. 34-5) (describing two cases of giant cell arteritis and rheumatoid
arthritis that appeared following receipt of influenza (“flu”) and tetanus toxoid vaccines).

        To connect the Tdap vaccine with GBS, Dr. Simpson referenced several somewhat-old
case reports involving the tetanus toxoid vaccine. Simpson First Rep. at 7; N. Newton and A.
Janati, Guillain-Barré Syndrome after Vaccination with Purified Tetanus Toxoid, 80 Southern
Med. J. 1053, 1054 (1987), filed as Ex. 43 (ECF No. 34-12) (“Newton & Janati”) (finding receipt
of tetanus toxoid-containing vaccine predated GBS symptoms by nine days, in “first reported case”
of such association); R. Bakshi and M. Graves, Guillain-Barré Syndrome after Combined Tetanus-
Diphtheria Toxoid Vaccination, 147 J. Neurol. Scr. 201 (1997), filed as Ex. 42 (ECF No. 34-11)


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(“Bakshi & Graves”) (discussing individual who satisfied the clinical, laboratory, and
neurophysiological criteria of GBS, with onset four days after receipt of a tetanus-diphtheria toxoid
vaccine). Bakshi & Graves was authored ten years after Newton & Janati—and by that date, the
authors noted, only three case reports of GBS after receipt of tetanus toxoid-containing vaccines
had been issued. Bakshi & Graves at 202.

        Dr. Simpson also briefly discussed an even older case report. J. Pollard and G. Selby,
Relapsing Neuropathy due to Tetanus Toxoid, 77 J. Neurol. Sci. 113 (1978), filed as 38 (ECF No.
34-7) (“Pollard & Selby”). Pollard & Selby involved a 42-year-old male who developed GBS after
receipt of a tetanus-diphtheria vaccine on three difference occasions over a thirteen-year
timeframe. Simpson First Rep. at 7. The patient’s pathological and immunological studies
demonstrated “similar pathogenetic mechanisms [that] are involved in the demyelination seen in
[a] post-inoculation polyneuropathy as in the more usual post-infective variety.” Thus, Pollard &
Selby concluded that “there is little doubt that the [patient’s] three clinical episodes of
demyelinating neuropathy resulted from the administration of tetanus toxoid.” Pollard & Selby at
117–18. (In fact, Pollard & Selby has been deemed to specifically involve chronic inflammatory
demyelinating polyneuropathy (“CIDP”), rather than GBS, which is an acute and monophasic
condition). 8

        Other support for a Tdap vaccine-GBS association was found, Dr. Simpson contended, in
certain government-related publications. In 2011, for example, the Advisory Committee on
Immunization Practice (the “ACIP”) had deemed the development of GBS within six weeks
following receipt of a tetanus toxoid-containing vaccine a precaution for subsequent vaccinations.
Simpson First Rep. at 8; Center for Disease Control, General Recommendations on Immunization:
Recommendations of the Advisory Committee on Immunization Practices (ACIP), MMWR 2011;
60 [No. RR-2]: 1-85 (January 28, 2011), filed as Ex. 46 (ECF No. 34-15) (“2011 ACIP Report”),
at 63. In addition, Dr. Simpson maintained that the Institute of Medicine (the “IOM”) had also
embraced a possible association. Simpson First Report at 8, citing K. Kretsinger et al., Preventing
Tetanus, Diphtheria, and Pertussis Among Adults: Use of Tetanus Toxoid, Reduced Diphtheria
Toxoid and Acellular Pertussis Vaccine, MMWR 2006; 55 [No. RR-17]: 1–47 (December 15,
2006), filed as Ex. 47 (ECF No. 34-16) (the “2006 MMWR Report”), at 15 (noting that the IOM-
embraced association was supported by a “single, well-documented case report”—Pollard & Selby
(see 2006 MMWR Report at 15 n.147)).

      Regarding the timeframe between Petitioner’s likely onset and date of vaccination, Dr.
Simpson maintained that Petitioner’s medical records established that her new neurological
symptoms (characterized by ascending numbness and paresthesias of the legs, lower extremity
weakness and gait difficulty) had begun within five days of vaccination. Simpson First Rep. at 8.

8
 See DeVaughn v. Sec'y of Health & Hum. Servs., No. 22-832V, 2025 WL 758128, at *21 n.21 (Fed. Cl. Spec. Mstr.
Feb. 10, 2025).

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Physical and diagnostic testing revealed objective neurological abnormalities, such as lower
extremity weakness, hypesthesia, decreased reflexes, and elevated protein of 122 with low WBC
count of 2. Id.; Ex. 10 at 16. The consensus among Petitioner’s treating physicians was GBS. First
Simpson Rep. at 8. Dr. Simpson opined that such a timeframe is consistent with a medically
acceptable temporal relationship between Tdap and GBS. Id.

         In concluding his first report, Dr. Simpson argued that “[t]here are no logical alternative
potential causes of [Petitioner’s] illness in this case other than [her] receipt of the Tdap vaccine.”
First Simpson Rep. at 8. He acknowledged that throughout 2019, Petitioner’s medical records
listed several diagnoses such as sinus infections, allergic rhinitis, bronchial spasm, cough, and a
cat allergy. Id. However, Dr. Simpson maintained that Petitioner’s treating physicians consistently
documented “that [her] neurological symptoms of GBS began after the vaccination.” Id. at 9.
Therefore, and based upon Petitioner’s clinical presentation and the overall sequence of events,
Dr. Simpson opined that “it is more likely than not that the administration of the Tdap vaccination
. . . caused her to develop GBS.” Id.

       Supplemental Report

        Dr. Simpson’s second written report briefly addressed a few comments found in the report
of Respondent’s expert, Dr. Matthew Brier. See generally Simpson Supp. Rep. at 1–3. He
disagreed with Dr. Brier’s assertion that Petitioner’s GBS began one day post-vaccination, with
complaints of back pain characterizing the onset of her disease. Id. at 1. Instead, Dr. Simpson
maintained that Petitioner had a “well-documented long-standing history of low back pain with
radicular symptoms in the lower extremities,” and that, “[the] recurrence of severe back pain on
[September 5, 2019] is completely consistent with [her] pre-existing history and [thus], i[t] is not
indicative of the onset of GBS.” Id.; see Ex. 10 at 25, 41; Ex. 11, 23, 41.

        Dr. Simpson also reiterated his opinion that such early complaints were distinguishable
from Petitioner’s development of new symptoms five days post-vaccination (i.e., ascending
numbness and paresthesias of the legs, lower extremity weakness, and gait difficulty). Simpson
Supp. Rep. at 2. Relying on the medical records, Dr. Simpson noted multiple instances in which
Petitioner’s post-vaccination symptoms were distinct from her pre-vaccination exams—noting that
“only mild distal [lower] [extremity] weakness was noted.” Id.; see also Ex. 9 at 51; Ex. 14 at 33.

       Second Supplemental Report

       Dr. Simpson provided a second supplemental report in the matter, hoping to bulwark his
proposed biological mechanism for how the tetanus vaccine can cause GBS in a susceptible
individual. Simpson Second Supp. Rep. at 1. He noted additional medical literature reports that
purport to demonstrate an association between the Tdap vaccine and GBS. See generally 2–4.


                                                  7
         In particular, Dr. Simpson emphasized Petitioner’s receipt of two Tdap vaccines within a
span of four years as impacting her immune response, making it more robust and essentially
triggering her GBS more quickly than usual. Simpson Second Supp. Rep. at 5. One item of
literature had observed that approximately “99% of all subjects under the age of 60 demonstrated
tetanus-specific antibody responses above the protective level of 0.01 IU/ml,” and that “the overall
half-life of tetanus-specific antibody was 14 years.” Id. at 5 (citing E. Hammarlund et al.,
Durability of Vaccine-Induced Immunity against Tetanus and Diphtheria Toxins: A Cross-
Sectional Analysis, 62 Clin Inf Dis 1111 (2016), filed as Ex. 62 (ECF No. 40-14)). It was therefore
“ reasonable to infer Petitioner’s tetanus toxoid antibody titers prior to the 2019 vaccination would
likely have been close to her titers following the 2015 tetanus vaccination, since the 4-year interval
was significantly less than the 14-year half-life of tetanus vaccine antibodies.” Simpson Second
Supp. Rep. at 5 (emphasis in original). Since Petitioner had received these two boosters within a
few years of each other, Dr. Simpson opined, it was likely that she “could have been more
‘susceptible’ to the second Tdap vaccination in 2019, triggering an aberrant immune response
resulting in GBS.” Id.

       B.      Respondent’s Expert — Matthew R. Brier, M.D., Ph.D.

       Dr. Brier, a neurologist, prepared a single written report in this matter. Report, dated Jan.
4, 2024, filed as Ex. A (ECF No. 35-1) (“Brier Rep.”).

        Dr. Brier attended the University of Texas at Dallas for his undergraduate degree, and
Washington University, St. Louis for his medical degree and Ph.D. See Curriculum Vitae, filed
Jan. 4, 2024 (ECF No. 35-2) (“Brier CV”); Brier Rep. at 1. He them completed an internship
followed by his residency in Neurology at Barnes Jewish Hospital in St. Louis, Missouri. Id.
Thereafter, Dr. Brier completed a fellowship in Multiple Sclerosis and Neuroimmunology at
Washington University School of Medicine, where he is currently an Assistant Professor of
Neurology and Radiology. Brier CV at 2; Brier Rep. at 1. He is board certified by the American
Board of Psychiatry and Neurology. Brier CV at 3. Dr. Brier primarily treats demyelinating
disorders of the central nervous system in his outpatient practice, but in an inpatient setting, he
frequently treats individuals with GBS and its mimicking disorders. Brier Rep. at 1. He has
published over forty peer-reviewed articles relating to the topics of neuroscience and neurology.
Id.; Brier CV a 6–13.

        Dr. Brier briefly discussed the pertinent medical history and facts herein before providing
his overall opinion regarding diagnosis and causation. See generally Brier Rep. at 2–5. GBS, he
explained, “is a monophasic, rapidly onsetting polyneuropathy.” Id. at 6. Petitioner’s medical
history was characterized by her acute onset of pain, paresthesia and radicular pain, followed by
distal to proximal weakness. Id. Moreover, she exhibited cranial nerve involvement, as well as
autonomic involvement throughout the course of her illness, thus making the overall diagnosis of
GBS most likely given her clinical presentation, in Dr. Brier’s opinion. Id.
                                                  8
         Dr. Brier, however, deemed Petitioner’s onset to have been very close-in-time to her
September 4, 2019 vaccination. First, he deemed significant her reports of back pain on September
5th, finding them to reflect “a clear deviation from [her] baseline,” and thus likely evidence of her
GBS onset. Brier Rep. at 7. Although the records did not explicitly note the difference in this pain
from her documented pre-vaccination concerns, Dr. Brier nevertheless noted that Petitioner’s
September 5, 2019 pain was different enough to cause her to visit the emergency department as
well as make several visits to her spine and pain management specialist—something she had not
done previously with respect to her chronic back pain. Id. Thus, Dr. Brier opined that this
worsening pain was “not simply an exacerbation of her chronic condition.” Id.

        Similarly, Dr. Brier noted the importance of Petitioner’s complaints of double vision the
day after vaccination, arguing that the improvement in Petitioner’s double vision via retracting an
eyelid or placing her chin down suggested that it “was caused by either a cranial nerve or central
process.” Brier Rep. at 7. Multiple forms of GBS are known to involve the cranial nerves, although
in this case the lack of electrodiagnostic testing did not permit identification of the GBS subtype
at issue. Id.; see also A. Gurwood & J. Drake, Guillain-Barré Syndrome, 77 Optometry – J. Am.
Optometric Association 540 (2006), filed as Ex. C (ECF No. 35-3) (“Gurwood & Drake”).
Nevertheless, “given [ ] the double vision onset around the time of the other GBS symptoms, that
GBS can cause oculomotor symptoms leading to double vision, that the double vision resolved
with treatment of GBS, and that no other etiologies were found for the double vision,” Petitioner’s
double vision was more likely than not an aspect (and early harbinger) of her later-diagnosed GBS,
along with her initial back pain complaints. Brier Rep. at 7; M. Dinkin, Diagnostic Approach to
Diplopia, 20 Continuum: Lifelong Learning in Neurology 942 (2014), filed as Ex. D (ECF No.
35-4).

       In fact, Dr. Brier noted, Petitioner had on September 5th complained of vision-related issues
predating vaccination. This meant that her GBS onset may well have begun before September 4,
2019. Brier Rep. at 7. But even if Dr. Brier were to disregard Petitioner’s visual disturbance, the
presence of new, objective weakness by September 6, 2019—two days post-vaccination—did not
align with the case reports cited by Petitioner. Id. at 7, 9 (referencing Bakshi & Graves (GBS onset
four days after vaccination), Newton & Janati (GBS nine days post-vaccination), and Pollard &
Selby (GBS recurrence no sooner than ten days, and after third dose of tetanus toxin). Otherwise,
Dr. Brier deemed case reports to “only serve to establish that it is possible for one event (GBS) to
follow another (vaccination), which is likely to occur by chance.” Brier Rep. at 9.

        Dr. Brier also questioned Petitioner’s theory of causation, criticizing Dr. Simpson’s claim
that “[t]here is ample support in the medical literature for a connection between vaccination of
various types and occurrence of demyelinating neuropathy.” Brier Rep. at 8 (citing Simpson First
Rep. at 7). He noted that much of the referenced literature was inapposite, since it pertained to the
putative association between GBS and either the swine flu or the seasonal flu vaccines, and


                                                 9
therefore such evidence “does not [also] show that [the] Tdap [vaccine] causes GBS.” Brier Rep.
at 8; see also Safranek at 940 (discussing relationship between GBS and swine flu vaccine); J.
Pritchard et al., Risk of Relapse of Guillain-Barré Syndrome or Chronic Inflammatory
Demyelinating Polyradiculoneuropathy following Immunisation, 73 J. Neurol Neurosurg.
Psychiatry 348–49 (2002), filed as Ex. 39 (ECF No. 34-8) (“Pritchard”). Pritchard was a
questionnaire survey in which 3.5% of 311 GBS patients reported recurrence of symptoms after
immunization (including tetanus-containing vaccines), but Pritchard’s authors deemed the risk to
be low and acknowledged that the study posed response bias methodologic limitations that reduced
the predictive validity of its findings). Pritchard at 349.

        Dr. Brier further maintained that certain IOM publications or reports were far less
supportive of causation than assumed by Dr. Simpson. The alleged IOM acceptance of the causal
relationship between tetanus-containing vaccines and GBS, for example, relied on the findings
from Pollard & Selby—a case report later deemed not to have been substantiated by subsequent
research. Brier Rep. at 9–10; 2006 MMWR Report at 15. Moreover, an updated version of the
IOM report on adverse events associated with different vaccines had actually concluded that “[t]he
evidence is inadequate to accept or reject a causal relationship between diphtheria toxoid-, tetanus
toxoid-, or acellular pertussis- containing vaccines and GBS.” Brier Rep. at 10 (quoting Institute
of Medicine, Adverse Effects of Vaccines: Evidence and Causality (K. Stratton et al., eds. 2012),
filed as Ex. E (ECF No. 35-5) (“2012 IOM Report”), at 558).

       In addition, several larger studies demonstrated a decreased risk of GBS following receipt
of a Tdap vaccine, or failed to identify GBS as a safety signal following the vaccine’s
administration. Brier Rep. at 10–11; J. Tuttle et al., The Risk of Guillain-Barré Syndrome after
Tetanus-Toxoid-Containing Vaccines in Adults and Children in the United States, 87 Am. J. Public
Health 2045, 2048 (1997), filed as Ex. F (ECF No. 35-6) (“Tuttle”) (concluding that “[i]f an
association [between tetanus-toxoid-containing vaccines and GBS] exists, it must be extremely
rate and not of public health significant.”) P. Haber et al., Safety Review of Tetanus Toxoid,
Reduced Diphtheria Toxoid, Acellular Pertussis Vaccines (Tdap) in Adults Aged ≥ 65 Years,
Vaccine Adverse Event Reporting System (VAERS), United States, September 2010 – December
2018, 38 Vaccine 1476, 1480 (2020), filed as Ex. G (ECF No. 35-7) (identifying no new safety
concerns over approximately a decade of recommended Tdap use for adults 65 years or older).

         Dr. Brier concluded his report reiterating that Petitioner’s symptoms had likely begun
within no later than a day or two of vaccination—a timeframe wholly unsupported by any
literature. Brier Rep. at 11. And the evidence offered to suggest a causal link between the Tdap
vaccine and GBS, is “circumstantial and larger, more well-done studies fail to find an association,”
according to Dr. Brier. Id. Thus, it was more likely than not that Petitioner’s development of GBS
was not the result of her receipt of the Tdap vaccine. Id.



                                                10
III.     Procedural History

        The claim was initiated in July 2022, and activated in September 2022 after completion of
“pre-assignment review” (performed in all Vaccine Program cases to ensure sufficient records
have been filed for case review). Petitioner’s former counsel withdrew from the matter in July
2023 and a Consented Motion to Substitute Counsel was subsequently granted. See Clerk’s Notice,
filed July 25, 2023. Thereafter, the process of obtaining expert reports began, with the final report
from Dr. Simpson filed in August 2024. The parties have now briefed their respective positions,
and the matter is ripe for resolution.

IV.      Parties’ Arguments

         Petitioner

        Petitioner maintains she has provided preponderant evidence of a credible medical theory
causally connecting the Tdap vaccine to the development of GBS. Br. at 22. Dr. Simpson primarily
replies upon the theory of molecular mimicry “as the most established mechanism,” as it “suggests
that epitopes of a virus or vaccine, results in development of immune antibodies and/or T cells that
could cross-react with epitopes on myelin or axonal glycoproteins of nerves, leading to neuronal
damage.” Id., citing Levin et al., Neuronal Molecular Mimicry in Immune-Mediated Neurologic
Disease, 44 Annals of Neurology 87 (1998), filed as Ex. 36 (ECF No. 34-5). Moreover, his
dependence upon the findings of a 1994 IOM report, which “discussed the evidence linking GBS
to both the swine flu vaccine and rabies vaccine,” is both relevant and reasonable herein. Br. at 26.
Petitioner acknowledges that the 2012 IOM report concluded that the evidence was “inadequate to
accept or reject a causal relationship between diphtheria toxoid-, tetanus toxoid-, or acellular
pertussis-containing vaccines and GBS;” but maintains that Dr. Simpson correctly interpreted its
findings as an “independent conclusion.” Id. at 30, citing 2012 IOM Report at 587. Additionally,
Petitioner argues that Dr. Simpson—having coupled case reports 9 with other evidence, such as the
1994 IOM report—has represented by preponderance of evidence a sound and reliable medical
theory causally connecting the vaccination and the injury. Br. at 36.

        Next, Petitioner argues that she has presented preponderant evidence of a logical sequence
of cause and effect showing that the Tdap vaccine caused her GBS. Br. at 42. To bulwark this
assertion, Petitioner first notes the numerous treating physicians that causally connected her GBS
to her September 4, 2019 vaccination. Id. at 43; see also Ex. 12 at 161, 168, 207; Ex. 28 at 79. She
similarly maintains she suffered a robust systematic reaction to the vaccination, as evidenced by
her documented treatment for myalgia pain, malaise, fatigue and dizziness within two days post-
vaccination. Br. at 44. Accordingly, Petitioner contends that such symptomatology “exhibited a

9
  Petitioner is aware of the Program’s view on case reports, however acknowledging that case reports are “[s]ituated
on the lower end of the evidentiary scale, [and that] case reports rarely purport to establish causation definitively.” Br.
at 34.

                                                           11
clinically apparent immune response, emblematic of a severe reaction to the Tdap vaccine.” Id.
And having received a Tdap vaccination in 2015, Petitioner purports that she ultimately was not
“immunologically naïve to the vaccine’s components in 2019,” but instead was “primed” by it to
develop a strong secondary adaptive immune response, resulting in her development of GBS. Id.
at 46.

        As to the third Althen Prong, Petitioner maintains her onset of GBS occurred within a
medically acceptable timeframe following her receipt of the Tdap vaccination. Br. at 47; Althen v.
Sec'y of Health & Hum. Servs., 418 F.3d 1274, 1278 (Fed. Cir. 2005). Specifically, she points to
record evidence documenting neurological symptoms beginning approximately five days post-
vaccination, followed by progressive neurological signs of sensory and motor neuropathy, as
falling within what is generally accepted in the medical literature regarding GBS post-vaccination.
Id. at 48; see also Ex. 12 at 86 (discussing 9/11/2019 ER consultation with Dr. Talbert who noted
petitioner has “increasing weakness in lower extremities [and] paresthesias to the right leg which
is new since previous visit [on 9/6/2019].” Dr. Simpson further explains that Petitioner’s clinical
course aligns with an autoimmune cross-reaction with molecular mimicry via the adaptive immune
response. Br. at 49. Petitioner disagrees with Dr. Brier’s assertion that her back pain on September
5, 2019, represented “a clear deviation from [her] baseline [pain],” but instead maintains it
reflected her pre-existing history of low back pain and “not indicative of the onset of [her] GBS.”
Id. at 50, 52.

        In her reply, Petitioner maintains her ability to satisfy all three Althen prongs. Reply at 26.
She contends that preponderant evidence exists to sufficiently demonstrate her development of
GBS was not only caused by her receipt of the Tdap vaccine, but that Dr. Simpson put forth a
sound and reliable biological mechanism—i.e., molecular mimicry—to causally link the vaccine
and GBS. Id. Dr. Simpson’s assertions, explains Petitioner, are “based upon the general
understanding of GBS [and its] pathophysiology,” emphasizing that “vaccines beyond the flu
vaccine, including Tdap, can be implicated as triggers of GBS.” Id. Petitioner further maintains
the significance of Dr. Simpson’s reliance on IOM reports finding that Tdap can cause GBS;
studies suggesting an association between the natural tetanus infection and GBS; and public
warnings regarding Tdap vaccines in individuals who have suffered GBS. Moreover, and in
conjunction with treater statements causally connecting Petitioner’s GBS with her receipt of the
Tdap vaccination, as well as the (alleged) five-day onset of her neurologic symptoms, Petitioner
contends she has satisfied her burden under Althen by offering preponderant evidence
demonstrating that her GBS was caused by her September 4, 2019 vaccination. Id. at 27.
Additionally, Petitioner disagrees with Respondent’s assertion that her reported double vision and
low back pain were evidence of an earlier onset. In so maintaining, Petitioner argues that
Respondent “ignores” the medical records and facts of this case which, according to Petitioner,
allow for the assumption that such symptoms could be associated with causes other than GBS (i.e.,
Petitioner’s well-documented chronic sinusitis or chronic low back pain). Id.


                                                  12
       Respondent

          Respondent does not dispute Petitioner’s diagnosis of GBS, but maintains that Petitioner
has failed to satisfy her burden under Althen. Opp. at 13. Regarding prong one, Respondent argues
that Petitioner has failed to present a reliable medical theory causally connecting the vaccination
and her injury. Id. at 19. Epidemiology does not support Petitioner’s claim. Id. Earlier IOM reports,
he argues, “failed to consider, unlike the 2012 committee, that the [Pollard & Selby] case report
does not involve GBS at all,” but instead “is properly characterized as a case report of [CIDP].”
Id. Moreover, earlier IOM reports are undermined by the conclusion of the 2012 IOM Report, with
little to no new evidence developed since that might support the contention that tetanus-containing
vaccines “can cause” GBS or CIDP, and the Program has repeatedly rejected reliance on Pollard
& Selby. Id. at 20.

        Respondent also maintains that the Government does not acknowledge a post-vaccination
risk of GBS following receipt of a tetanus toxoid-containing vaccine, as suggested in Mohamad v.
Sec’y of Health & Hum. Servs., No. 16-1075V, 2022 WL 711604, at *18 (Fed. Cl. Spec. Mstr. Jan
27, 2022), mot. for review den’d, No. 16-1075V, 2024 WL 4993421 (Fed. Cl. Nov. 12, 2024),
appeal dismissed, No. 2025-1370, 2025 WL 1341189 (Fed. Cir. May 8, 2025). Respondent in fact
disagrees with the special master’s interpretation and evaluation of the evidence submitted in
Mohamad—noting specifically that the “IOM ‘concluded that the evidence was inadequate to
accept or reject a causal relation between receipt of diphtheria toxoid- and tetanus toxoid-
containing vaccine’ and GBS.” Opp. at 22, citing Center for Disease Control & Prevention,
Prevention of Pertussis, Tetanus, and Diphtheria with Vaccines in the United States:
Recommendations of the Advisory Committee on Immunization Practices (ACIP), 67(2) CDC
Morbidity        &         Mortality       Wkly.      Rep.       1      (Apr.       27,     2028),
https://www.cdc.gov/mmwr/volumes/67/rr/pdfs/rr6702a1-H.pdf (last visited June 13, 2025).
Additionally epidemiological studies have consistently rejected a vaccine association. Opp. at 23;
see also Tuttle at 1. And Dr. Simpson favors molecular mimicry as a possible mechanism mainly
because it has scientific support in the context of GBS mediated by a wild infection—but otherwise
the “non-specific invocation of molecular mimicry” has previously been rejected by this Court as
“too generic to be a persuasive theory of causation in a specific case. Opp. at 27 citing W.C. v.
Sec’y of Health & Hum. Servs., 704 F.3d 1352 (Fed. Cir. 2013).

        Similarly, Respondent maintains that Petitioner has failed to show a logical sequence of
cause and effect between the Tdap vaccination and her GBS. Opp. at 30. According to Respondent,
Petitioner presented no evidence demonstrating “that the manifestation of [her] GBS was somehow
aberrant from a typical manifestation of GBS absent vaccination,” and thus, her contention that
the tetanus vaccination acts “as an inciting prodrome event” is not well supported. Id. at 31.
Moreover, Respondent argues that Dr. Simpson’s speculation—that Petitioner’s prior receipt of a
Tdap vaccine in 2015 could have caused her to be more “susceptible” to the second dose in 2019—


                                                 13
lacks “a hypothesis of how pre-existing antibodies might make [P]etitioner more susceptible to
GBS.” Id. Instead, Respondent maintains, “[i]f anything, the 2015 vaccination demonstrates that
[P]etitioner has a history of tolerating the vaccine, making it less likely that her 2019 vaccination
caused her GBS.” Id. And while Petitioner relies on several treater statements as further evidence
of causation, such statements do not satisfy her burden under Althen Prong Two, and that
“[s]pecific attribution of GBS to vaccination is not truly discussed.” Id. at 32. Therefore, the treater
statements—which only were based on a temporal relationship, according to Respondent—are
insufficient additional support for causation. Opp. at 32.

        Lastly, Respondent argues that Petitioner has failed to establish a medically-appropriate
temporal relationship between her receipt of the Tdap vaccine and the onset of her GBS—noting
that her “GBS more likely than not predated vaccination and consisted of blurry vision/diplopia.”
Id. at 14. Based on the clinical presentation, Dr. Brier’s opinion regarding Petitioner’s visual
symptomatology as the more likely onset of her GBS is well supported. Id. at 15. And the medical
records do not demonstrate pansinusitis as the cause of Petitioner’s visual disturbances which
began acutely prior to her vaccination. See Ex. 12 at 370 (documenting improved visual
impairments on discharge despite presence of pansinusitis on 9/11/2019 brain and orbit MRI).
Petitioner continued to experience a progressive nature of pansinusitis on imaging, but her vision
issues improved along with the improvement in her GBS symptomatology. Opp. at 14.
Accordingly, Respondent maintains that the aligned improvement in visual and GBS symptoms
ultimately supports the contention that her visual disturbances were more likely than not a
manifestation of her GBS—thus, putting onset prior to vaccination. Id. at 14–15.

        Respondent also discounts Petitioner’s argument that her initial back pain symptoms were
a continuation of her pre-vaccination status, rather than the start of her GBS. Although Petitioner
had lumbar stenosis prior to her vaccination “secondary to [a] large synovial cyst and dynamic
spondylolisthesis,” she had experienced a near complete resolution of pain a little over a year prior
to her receipt of the Tdap vaccine. Id. at 16 (citing Ex. 7 at 7). Moreover, the sudden/acute nature
of Petitioner’s GBS and vision symptoms suggest her post-vaccination symptoms were
distinguishable from her otherwise well-documented and longstanding back issues. Id.

V.     Applicable Law

       A.      Petitioner’s Overall Burden in Vaccine Program Cases

        To receive compensation in the Vaccine Program, a petitioner must prove either: (1) that
he suffered a “Table Injury”—i.e., an injury falling within the Vaccine Injury Table—
corresponding to one of the vaccinations in question within a statutorily prescribed period of time
or, in the alternative, (2) that his illnesses were actually caused by a vaccine (a “Non-Table
Injury”). See Sections 13(a)(1)(A), 11(c)(1), and 14(a), as amended by 42 C.F.R. § 100.3; §


                                                  14
11(c)(1)(C)(ii)(I); see also Moberly, 592 F.3d at 1321; Capizzano v. Sec’y of Health & Hum. Servs.,
440 F.3d 1317, 1320 (Fed. Cir. 2006). 10 There is no Table claim for GBS caused by a tetanus-
containing vaccine.

        For both Table and Non-Table claims, Vaccine Program petitioners bear a “preponderance
of the evidence” burden of proof. Section 13(1)(a). That is, a petitioner must offer evidence that
leads the “trier of fact to believe that the existence of a fact is more probable than its nonexistence
before [he] may find in favor of the party who has the burden to persuade the judge of the fact’s
existence.” Moberly, 592 F.3d at 1322 n.2; see also Snowbank Enter. v. United States, 6 Cl. Ct.
476, 486 (1984) (mere conjecture or speculation is insufficient under a preponderance standard).
Proof of medical certainty is not required. Bunting v. Sec’y of Health & Hum. Servs., 931 F.2d 867,
873 (Fed. Cir. 1991). In particular, a petitioner must demonstrate that the vaccine was “not only
[the] but-for cause of the injury but also a substantial factor in bringing about the injury.” Moberly,
592 F.3d at 1321 (quoting Shyface, 165 F.3d at 1352–53); Pafford v. Sec’y of Health & Hum.
Servs., 451 F.3d 1352, 1355 (Fed. Cir. 2006). A petitioner may not receive a Vaccine Program
award based solely on his assertions; rather, the petition must be supported by either medical
records or by the opinion of a competent physician. Section 13(a)(1).

        In attempting to establish entitlement to a Vaccine Program award of compensation for a
Non-Table claim, a petitioner must satisfy all three of the elements established by the Federal
Circuit in Althen v. Sec'y of Health & Hum. Servs., 418 F.3d 1274, 1278 (Fed. Cir. 2005): “(1) a
medical theory causally connecting the vaccination and the injury; (2) a logical sequence of cause
and effect showing that the vaccination was the reason for the injury; and (3) a showing of
proximate temporal relationship between vaccination and injury.”

        Each of the Althen prongs requires a different showing. Under Althen prong one, petitioners
must provide a “reputable medical theory,” demonstrating that the vaccine received can cause the
type of injury alleged. Pafford, 451 F.3d at 1355–56 (citations omitted). To satisfy this prong, a
petitioner’s theory must be based on a “sound and reliable medical or scientific explanation.”
Knudsen v. Sec’y of Health & Hum. Servs., 35 F.3d 543, 548 (Fed. Cir. 1994). Such a theory must
only be “legally probable, not medically or scientifically certain.” Id. at 549.

       Petitioners may satisfy the first Althen prong without resort to medical literature,
epidemiological studies, demonstration of a specific mechanism, or even a generally accepted
medical theory. Andreu, 569 F.3d at 1378–79 (citing Capizzano, 440 F.3d at 1325–26). Special
masters, despite their expertise, are not empowered by statute to conclusively resolve what are

10
  Decisions of special masters (some of which I reference in this ruling) constitute persuasive but not binding
authority. Hanlon v. Sec’y of Health & Hum. Servs., 40 Fed. Cl. 625, 630 (1998). By contrast, Federal Circuit rulings
concerning legal issues are binding on special masters. Guillory v. Sec’y of Health & Hum. Servs., 59 Fed. Cl. 121,
124 (2003), aff’d 104 F. Appx. 712 (Fed. Cir. 2004); see also Spooner v. Sec’y of Health & Hum. Servs., No. 13-159V,
2014 WL 504728, at *7 n.12 (Fed. Cl. Spec. Mstr. Jan. 16, 2014).

                                                        15
essentially thorny scientific and medical questions, and thus scientific evidence offered to establish
Althen prong one is viewed “not through the lens of the laboratorian, but instead from the vantage
point of the Vaccine Act’s preponderant evidence standard.” Id. at 1380. Accordingly, special
masters must take care not to increase the burden placed on petitioners in offering a scientific
theory linking vaccine to injury. Contreras, 121 Fed. Cl. at 245.

        In discussing the evidentiary standard applicable to the first Althen prong, the Federal
Circuit has consistently rejected the contention that it can be satisfied merely by establishing the
proposed causal theory’s scientific or medical plausibility. See Kalajdzic v. Sec’y of Health &
Hum. Servs., No. 2023-1321, 2024 WL 3064398, at *2 (Fed. Cir. June 20, 2024) (arguments “for
a less than preponderance standard” deemed “plainly inconsistent with our precedent” (citing
Moberly, 592 F.3d at 1322)); Boatmon v. Sec’y of Health & Hum. Servs., 941 F.3d 1351, 1359
(Fed. Cir. 2019); see also Howard v. Sec'y of Health & Hum. Servs., 2023 WL 4117370, at *4
(Fed. Cl. May 18, 2023) (“[t]he standard has been preponderance for nearly four decades”), aff’d,
2024 WL 2873301 (Fed. Cir. June 7, 2024) (unpublished). And petitioners always have the
ultimate burden of establishing their overall Vaccine Act claim with preponderant evidence. W.C.
v. Sec’y of Health & Hum. Servs., 704 F.3d 1352, 1356 (Fed. Cir. 2013) (citations omitted); Tarsell
v. United States, 133 Fed. Cl. 782, 793 (2017) (noting that Moberly “addresses the petitioner’s
overall burden of proving causation-in-fact under the Vaccine Act” by a preponderance standard).

        The second Althen prong requires proof of a logical sequence of cause and effect, usually
supported by facts derived from a petitioner’s medical records. Althen, 418 F.3d at 1278; Andreu,
569 F.3d at 1375–77; Capizzano, 440 F.3d at 1326; Grant v. Sec’y of Health & Hum. Servs., 956
F.2d 1144, 1148 (Fed. Cir. 1992). In establishing that a vaccine “did cause” injury, the opinions
and views of the injured party’s treating physicians are entitled to some weight. Andreu, 569 F.3d
at 1367; Capizzano, 440 F.3d at 1326 (“medical records and medical opinion testimony are favored
in vaccine cases, as treating physicians are likely to be in the best position to determine whether a
‘logical sequence of cause and effect show[s] that the vaccination was the reason for the injury’”)
(quoting Althen, 418 F.3d at 1280). Medical records are generally viewed as particularly
trustworthy evidence, since they are created contemporaneously with the treatment of the patient.
Cucuras v. Sec’y of Health & Hum. Servs., 993 F.2d 1525, 1528 (Fed. Cir. 1993).

        Medical records and statements of a treating physician, however, do not per se bind the
special master to adopt the conclusions of such an individual, even if they must be considered and
carefully evaluated. Section 13(b)(1) (providing that “[a]ny such diagnosis, conclusion, judgment,
test result, report, or summary shall not be binding on the special master or court”); Snyder v. Sec’y
of Health & Hum. Servs., 88 Fed. Cl. 706, 746 n.67 (2009) (“there is nothing . . . that mandates
that the testimony of a treating physician is sacrosanct—that it must be accepted in its entirety and
cannot be rebutted”). As with expert testimony offered to establish a theory of causation, the
opinions or diagnoses of treating physicians are only as trustworthy as the reasonableness of their


                                                 16
suppositions or bases. The views of treating physicians should be weighed against other, contrary
evidence also present in the record—including conflicting opinions among such individuals.
Hibbard v. Sec’y of Health & Hum. Servs., 100 Fed. Cl. 742, 749 (2011) (not arbitrary or capricious
for special master to weigh competing treating physicians’ conclusions against each other), aff’d,
698 F.3d 1355 (Fed. Cir. 2012); Veryzer v. Sec’y of Dept. of Health & Hum. Servs., No. 06-522V,
2011 WL 1935813, at *17 (Fed. Cl. Spec. Mstr. Apr. 29, 2011), mot. for review den’d, 100 Fed.
Cl. 344, 356 (2011), aff’d without opinion, 475 F. Appx. 765 (Fed. Cir. 2012).

        The third Althen prong requires establishing a “proximate temporal relationship” between
the vaccination and the injury alleged. Althen, 418 F.3d at 1281. That term has been equated to the
phrase “medically-acceptable temporal relationship.” Id. A petitioner must offer “preponderant
proof that the onset of symptoms occurred within a timeframe which, given the medical
understanding of the disorder’s etiology, it is medically acceptable to infer causation.” de Bazan v.
Sec’y of Health & Hum. Servs., 539 F.3d 1347, 1352 (Fed. Cir. 2008). The explanation for what is
a medically acceptable timeframe must align with the theory of how the relevant vaccine can cause
an injury (Althen prong one’s requirement). Id. at 1352; Shapiro v. Sec’y of Health & Hum. Servs.,
101 Fed. Cl. 532, 542 (2011), recons. den’d after remand, 105 Fed. Cl. 353 (2012), aff’d mem.,
503 F. Appx. 952 (Fed. Cir. 2013); Koehn v. Sec’y of Health & Hum. Servs., No. 11-355V, 2013
WL 3214877 (Fed. Cl. Spec. Mstr. May 30, 2013), mot. for rev. den’d (Fed. Cl. Dec. 3, 2013),
aff’d, 773 F.3d 1239 (Fed. Cir. 2014).

       B.      Legal Standards Governing Factual Determinations

        The process for making determinations in Vaccine Program cases regarding factual issues
begins with consideration of the medical records. Section 11(c)(2). The special master is required
to consider “all [ ] relevant medical and scientific evidence contained in the record,” including
“any diagnosis, conclusion, medical judgment, or autopsy or coroner's report which is contained
in the record regarding the nature, causation, and aggravation of the petitioner's illness, disability,
injury, condition, or death,” as well as the “results of any diagnostic or evaluative test which are
contained in the record and the summaries and conclusions.” Section 13(b)(1)(A). The special
master is then required to weigh the evidence presented, including contemporaneous medical
records and testimony. See Burns v. Sec'y of Health & Hum. Servs., 3 F.3d 415, 417 (Fed. Cir.
1993) (determining that it is within the special master's discretion to determine whether to afford
greater weight to contemporaneous medical records than to other evidence, such as oral testimony
surrounding the events in question that was given at a later date, provided that such determination
is evidenced by a rational determination).

       As noted by the Federal Circuit, “[m]edical records, in general, warrant consideration as
trustworthy evidence.” Cucuras, 993 F.2d at 1528; Doe/70 v. Sec'y of Health & Hum. Servs., 95
Fed. Cl. 598, 608 (2010) (“[g]iven the inconsistencies between petitioner's testimony and his


                                                  17
contemporaneous medical records, the special master's decision to rely on petitioner's medical
records was rational and consistent with applicable law”), aff'd, Rickett v. Sec'y of Health & Hum.
Servs., 468 F. App’x 952 (Fed. Cir. 2011) (non-precedential opinion). A series of linked
propositions explains why such records deserve some weight: (i) sick people visit medical
professionals; (ii) sick people attempt to honestly report their health problems to those
professionals; and (iii) medical professionals record what they are told or observe when examining
their patients in as accurate a manner as possible, so that they are aware of enough relevant facts
to make appropriate treatment decisions. Sanchez v. Sec'y of Health & Hum. Servs., No. 11–685V,
2013 WL 1880825, at *2 (Fed. Cl. Spec. Mstr. Apr. 10, 2013); Cucuras v. Sec'y of Health & Hum.
Servs., 26 Cl. Ct. 537, 543 (1992), aff'd, 993 F.2d at 1525 (Fed. Cir. 1993) (“[i]t strains reason to
conclude that petitioners would fail to accurately report the onset of their daughter's symptoms”).

        Accordingly, if the medical records are clear, consistent, and complete, then they should
be afforded substantial weight. Lowrie v. Sec'y of Health & Hum. Servs., No. 03–1585V, 2005 WL
6117475, at *20 (Fed. Cl. Spec. Mstr. Dec. 12, 2005). Indeed, contemporaneous medical records
are often found to be deserving of greater evidentiary weight than oral testimony—especially
where such testimony conflicts with the record evidence. Cucuras, 993 F.2d at 1528; see also
Murphy v. Sec'y of Health & Hum. Servs., 23 Cl. Ct. 726, 733 (1991), aff'd per curiam, 968 F.2d
1226 (Fed. Cir. 1992), cert. den'd, Murphy v. Sullivan, 506 U.S. 974 (1992) (citing United States
v. United States Gypsum Co., 333 U.S. 364, 396 (1947) (“[i]t has generally been held that oral
testimony which is in conflict with contemporaneous documents is entitled to little evidentiary
weight.”)).

       However, the Federal Circuit has also noted that there is no formal “presumption” that
records are accurate or superior on their face to other forms of evidence. Kirby v. Sec’y of Health
& Hum. Servs., 997 F.3d 1378, 1383 (Fed. Cir. 2021). There are certainly situations in which
compelling oral or written testimony (provided in the form of an affidavit or declaration) may be
more persuasive than written records, such as where records are deemed to be incomplete or
inaccurate. Campbell v. Sec'y of Health & Hum. Servs., 69 Fed. Cl. 775, 779 (2006) (“like any
norm based upon common sense and experience, this rule should not be treated as an absolute and
must yield where the factual predicates for its application are weak or lacking”); Lowrie, 2005 WL
6117475, at *19 (“[w]ritten records which are, themselves, inconsistent, should be accorded less
deference than those which are internally consistent”) (quoting Murphy, 23 Cl. Ct. at 733)).
Ultimately, a determination regarding a witness's credibility is needed when determining the
weight that such testimony should be afforded. Andreu, 569 F.3d at 1379; Bradley v. Sec'y of
Health & Hum. Servs., 991 F.2d 1570, 1575 (Fed. Cir. 1993).

      When witness testimony is offered to overcome the presumption of accuracy afforded to
contemporaneous medical records, such testimony must be “consistent, clear, cogent, and
compelling.” Sanchez, 2013 WL 1880825, at *3 (citing Blutstein v. Sec'y of Health & Hum. Servs.,


                                                 18
No. 90–2808V, 1998 WL 408611, at *5 (Fed. Cl. Spec. Mstr. June 30, 1998)). In determining the
accuracy and completeness of medical records, the Court of Federal Claims has listed four possible
explanations for inconsistencies between contemporaneously created medical records and later
testimony: (1) a person's failure to recount to the medical professional everything that happened
during the relevant time period; (2) the medical professional's failure to document everything
reported to her or him; (3) a person's faulty recollection of the events when presenting testimony;
or (4) a person's purposeful recounting of symptoms that did not exist. La Londe v. Sec'y of Health
& Hum. Servs., 110 Fed. Cl. 184, 203–04 (2013), aff'd, 746 F.3d 1334 (Fed. Cir. 2014). In making
a determination regarding whether to afford greater weight to contemporaneous medical records
or other evidence, such as testimony at hearing, there must be evidence that this decision was the
result of a rational determination. Burns, 3 F.3d at 417.

       C.      Analysis of Expert Testimony

        Establishing a sound and reliable medical theory often requires a petitioner to present
expert testimony in support of his claim. Lampe v. Sec’y of Health & Hum. Servs., 219 F.3d 1357,
1361 (Fed. Cir. 2000). Vaccine Program expert testimony is usually evaluated according to the
factors for analyzing scientific reliability set forth in Daubert v. Merrell Dow Pharm., Inc., 509
U.S. 579, 594–96 (1993). See Cedillo v. Sec’y of Health & Hum. Servs., 617 F.3d 1328, 1339 (Fed.
Cir. 2010) (citing Terran v. Sec’y of Health & Hum. Servs., 195 F.3d 1302, 1316 (Fed. Cir. 1999).
Under Daubert, the factors for analyzing the reliability of testimony are:

       (1) whether a theory or technique can be (and has been) tested; (2) whether the theory or
       technique has been subjected to peer review and publication; (3) whether there is a known
       or potential rate of error and whether there are standards for controlling the error; and (4)
       whether the theory or technique enjoys general acceptance within a relevant scientific
       community.

Terran, 195 F.3d at 1316 n.2 (citing Daubert, 509 U.S. at 592–95).

         In the Vaccine Program the Daubert factors play a slightly different role than they do when
applied in other federal judicial settings, like the district courts. Typically, Daubert factors are
employed by judges (in the performance of their evidentiary gatekeeper roles) to exclude evidence
that is unreliable or could confuse a jury. By contrast, in Vaccine Program cases these factors are
used in the weighing of the reliability of scientific evidence proffered. Davis v. Sec'y of Health &
Hum. Servs., 94 Fed. Cl. 53, 66–67 (2010) (“uniquely in this Circuit, the Daubert factors have been
employed also as an acceptable evidentiary-gauging tool with respect to persuasiveness of expert
testimony already admitted”). The flexible use of the Daubert factors to evaluate the
persuasiveness and reliability of expert testimony has routinely been upheld. See, e.g., Snyder, 88
Fed. Cl. at 742–45. In this matter (as in numerous other Vaccine Program cases), Daubert has not


                                                19
been employed at the threshold, to determine what evidence should be admitted, but instead to
determine whether expert testimony offered is reliable and/or persuasive.

        Respondent frequently offers one or more experts in order to rebut a petitioner’s case.
Where both sides offer expert testimony, a special master's decision may be “based on the
credibility of the experts and the relative persuasiveness of their competing theories.” Broekelschen
v. Sec'y of Health & Hum. Servs., 618 F.3d 1339, 1347 (Fed. Cir. 2010) (citing Lampe, 219 F.3d
at 1362). However, nothing requires the acceptance of an expert's conclusion “connected to
existing data only by the ipse dixit of the expert,” especially if “there is simply too great an
analytical gap between the data and the opinion proffered.” Snyder, 88 Fed. Cl. at 743 (quoting
Gen. Elec. Co. v. Joiner, 522 U.S. 146 (1997)); see also Isaac v. Sec'y of Health & Hum. Servs.,
No. 08–601V, 2012 WL 3609993, at *17 (Fed. Cl. Spec. Mstr. July 30, 2012), mot. for review
den'd, 108 Fed. Cl. 743 (2013), aff'd, 540 F. App’x. 999 (Fed. Cir. 2013) (citing Cedillo, 617 F.3d
at 1339). Weighing the relative persuasiveness of competing expert testimony, based on a
particular expert's credibility, is part of the overall reliability analysis to which special masters
must subject expert testimony in Vaccine Program cases. Moberly, 592 F.3d at 1325–26
(“[a]ssessments as to the reliability of expert testimony often turn on credibility determinations”);
see also Porter v. Sec'y of Health & Hum. Servs., 663 F.3d 1242, 1250 (Fed. Cir. 2011) (“this court
has unambiguously explained that special masters are expected to consider the credibility of expert
witnesses in evaluating petitions for compensation under the Vaccine Act”).

       D.      Consideration of Medical Literature

         Both parties filed numerous items of medical and scientific literature in this case, but not
all such items factor into the outcome of this decision. While I have reviewed all the medical
literature submitted in this case, I discuss only those articles that are most relevant to my
determination and/or are central to Petitioner’s case—just as I have not exhaustively discussed
every individual medical record filed. Moriarty v. Sec’y of Health & Hum. Servs., No. 2015–5072,
2016 WL 1358616, at *5 (Fed. Cir. Apr. 6, 2016) (“[w]e generally presume that a special master
considered the relevant record evidence even though he does not explicitly reference such evidence
in his decision”) (citation omitted); see also Paterek v. Sec’y of Health & Hum. Servs., 527 F.
App’x 875, 884 (Fed. Cir. 2013) (“[f]inding certain information not relevant does not lead to—and
likely undermines—the conclusion that it was not considered”).

       E.      Determination to Resolve Case without a Hearing

        I have opted to decide entitlement in this case based on written submissions and evidentiary
filings, including the expert reports filed by each side. The Vaccine Act and Rules not only
contemplate but encourage special masters to decide petitions on the papers rather than via
evidentiary hearing, where (in the exercise of their discretion) they conclude that the former means


                                                 20
of adjudication will properly and fairly resolve the case. Section 12(d)(2)(D); Vaccine Rule 8(d).
The choice to do so has been affirmed on appeal. See D'Toile v. Sec'y of Health & Human Servs.,
No. 15-85V, 2018 WL 1750619, at *2 (Fed. Cir. Apr. 12, 2018); see also Hooker v. Sec'y of Health
& Human Servs., No. 02-472V, 2016 WL 3456435, at *21 n.19 (Fed. Cl. Spec. Mstr. May 19,
2016) (citing numerous cases where special masters decided on the papers in lieu of hearing and
that decision was upheld). I am simply not required to hold a hearing in every matter, no matter
the preferences of the parties. See Hovey v. Sec'y of Health & Human Servs., 38 Fed. Cl. 397, 402-
03 (1997) (special master acted within his discretion in denying evidentiary hearing); Burns, 3 F.3d
at 417.

                                                    ANALYSIS

I.       Overview of GBS and its Treatment in Prior Program Cases

        GBS has been defined as an acute, monophasic peripheral neuropathy involving rapidly
progressive and ascending weakness and paralysis, which is thought to have an autoimmune
mechanism. P. Donofrio, Guillain-Barré Syndrome, 23 (5) Continuum J. 1295, 129 (2017), filed
as Ex. 34 (ECF No. 34-3). In a subset of patients, GBS can result in cranial nerve palsies, including
causing clinical symptoms like diplopia. Gurwood & Drake at 540–41 (documenting a case report
of a patient experiencing intermittent diplopia after hospitalization for symptoms later diagnosed
as GBS). Petitioner’s GBS diagnosis is not contested by Respondent. Opp. at 13.

        There is a large body of reasoned decisions 11 in which an association between the flu
vaccine and peripheral neuropathies—most often GBS—has been established. Indeed, flu vaccine-
caused GBS is a Table Claim. 42 C.F.R. § 100.3.14. This means the Government accepts that
sufficiently-probative and reliable science on the topic exists to justify conceding causation, at
least for Program purposes. Haskins v. Secretary of Health & Hum. Servs., No. 18-1776V, WL
2020 1870279 (Fed. Cl. Spec. Mstr. Mar. 13, 2019). Even in cases where a Table element for such
a claim cannot be met (for example, when onset is too short or too long to fit within the timeframe
of 3–42 days set for the claim), any subsequent causation-in-fact analysis performed by the special
masters does not usually require the claimant to offer proof in support of the “can cause” element;
instead, it is reasonably assumed to be satisfied. See Welch v. Sec’y of Health & Hum. Servs. No.
18-494V, 2019 WL 349360 (Fed. Cl. Spec. Mstr. July 2, 2019).

        Other vaccines have also been found causal of GBS, although there is disagreement among
the special masters as to the preponderant strength of these proposed associations. See, e.g., Gross
v. Sec’y of Health & Hum. Servs., No. 17-1075, 2022 WL 9669651, at *36–37 (Fed. Cl. Spec.

11
  Although prior decisions from different cases do not control the outcome herein, special masters may reasonably
take into account, for guidance, the logic of such reasoned determinations. In fact, it is wise to do so, given how often
similar causation theories or fact patterns arise in Vaccine Program cases.


                                                          21
Mstr. Sept. 22, 2022) (finding the pneumococcal vaccine caused GBS); but see Trollinger v. Sec’y
of Health & Hum. Servs., No. 16-473V, 2023 WL 2521912, at *30 (Fed. Cl. Spec. Mstr. Feb. 17,
2023), mot. for review den’d, 167 Fed. Cl. 127 (2023) (holding that the pneumococcal vaccine was
not shown to cause GBS); Bielak v. Sec’y of Health & Hum. Servs., No. 18-761V, 2022 WL
18058244, at *3 (Fed. Cl. Spec. Mstr. Dec. 9, 2022) (same). It thus cannot be said that the Program
has developed a consistent view as to what the science preponderantly “says” about causation of
GBS when the flu vaccine is not involved. Instead, it appears that the outcome in such cases is
mostly a function of the evidence before the special master, with no clear trend one way or the
other.

        This is definitely true for claims that the Tdap vaccine can cause GBS. Several cases
decided in the past ten years found no causal association between the two. See, e.g., Dennington
v. Sec'y of Health & Hum. Servs., No. 18-1303V, 2023 WL 2965239 (Fed. Cl. Spec. Mstr. Apr.
17, 2023), mot. for review den’d, 167 Fed. Cl. 640 (2023), appeal dismissed, No. 2024-1214, 2024
WL 1255318 (Fed. Cir. Mar. 25, 2024); Montgomery v. Sec’y of Health & Hum. Servs., No. 15-
1037V, 2019 WL 2511352 (Fed. Cl. Spec. Mstr. May 21, 2019); Tompkins v. Sec’y of Health &
Hum. Servs., No. 10-261V, 2013 WL 3498652 (Fed. Cl. Spec. Mstr. June 21, 2013), mot. for
review den’d, 117 Fed. Cl. 713 (2014); Isaac v. Sec’y of Health & Hum. Servs., No. 08-601V, 2012
WL 3609993 (Fed. Cl. Spec. Mstr. July 30, 2012), mot. for review den’d, 108 Fed. Cl. 743 (2012),
aff’d, 540 F. App’x 999 (Fed. Cir. 2013).

        I have also decided a few cases in which I determined that the petitioner failed to establish
a causal association between the Tdap vaccine and CIDP — a different injury from GBS, although
also still a peripheral neuropathy (and Program claimants frequently rely on GBS-specific
evidence in arguing that a vaccine can cause CIDP). See, e.g., DeVaughn v. Sec'y of Health &
Hum. Servs., No. 22-832V, 2025 WL 758128 (Fed. Cl. Spec. Mstr. Feb. 10, 2025); Howard v.
Sec’y of Health & Hum. Servs., No. 16-1592V, 2022 WL 4869354 (Fed. Cl. Spec. Mstr. Aug. 31,
2022), mot. for review den’d, No. 16-1592V, 2023 WL 4117370 (Fed. Cl. May 18, 2023), aff’d,
No. 2023-1816, 2024 WL 2873301 (Fed. Cir. June 7, 2024); Sanchez v. Sec’y of Health & Hum.
Servs., No. 18-1012V, 2022 WL 1013264, at *1 (Fed. Cl. Spec. Mstr. Mar. 11, 2022).

        Prior Tdap-GBS cases have often involved causation theories comparable to what is
offered in this case. In Isaac, for example, the petitioner proposed molecular mimicry as the causal
mechanism. Issac, 2012 WL 3609993, at *6. But the special master determined that the petitioner’s
expert had over-relied on a single case report 12 to prove causation, without adequately
substantiating the mechanism. Id. at *20–21. This determination was affirmed on appeal at the
Court of Federal Claims and Federal Circuit. In Tompkins, the special master denied entitlement
in a case alleging that a number of vaccines received at the same time (including Tdap) caused a

12
     The case report mentioned in Issac was Pollard & Selby.


                                                          22
petitioner’s GBS, but the causal theory put forward attempted to assert that the vaccines could also
individually trigger the disease. Tompkins, 2013 WL 3498652, at *15. The petitioner’s expert,
however, relied heavily on VAERS passive surveillance data, 13 and otherwise invoked a number
of theories (molecular mimicry, or endotoxin in tetanus-containing vaccines) that were only
cursorily substantiated. Id. at *19–23.

        I have in some of my relevant prior decisions also observed issues with the reliability of
the findings proposed by Pollard & Selby, one of the most on-point case reports offered herein. As
I noted in DeVaughn, 2025 WL 758128, at *20:

             Pollard & Selby deserves even less weight. In this quite-old case study, a
             patient's acute idiopathic polyneuropathy relapsed on three occasions, each
             purportedly following a tetanus vaccination. Pollard & Selby at 113. But its
             authors did not consider alternative explanations for these spontaneous
             relapses, nor did they provide evidence beyond a temporal association. . .
             The authors also failed to explain how, or by what mechanism, a tetanus
             toxoid antigen could stimulate CIDP, even if some association had been
             demonstrated in this single patient. . . . And Pollard & Selby's findings
             remain uncorroborated, over 45 years later, by subsequent (and more
             reliable) studies that might confirm what it suggests is possible. It cannot
             stand as persuasive evidence for causation. Tompkins, 2013 WL 3498652,
             at *26 (observing that an absence of evidence in the years after publication
             of a case report or series corroborating its suggestions about a vaccine-
             injury association undermines the initial report's causal significance, and
             suggests its findings reflect only chance).

        Admittedly, other special masters have deemed causation demonstrated in a Tdap vaccine-
GBS case. See Harris v. Sec’y of Health & Hum. Servs., No. 18-944V, 2023 WL 2583393 (Fed.
Cl. Spec. Mstr. Feb. 21, 2023); Mohamad, 2022 WL 711604, at *18. In Mohamad, a special master
ruled in petitioner’s favor in a Tdap-GBS case, but almost wholly based on the determination that
the Government had effectively conceded the first Althen Prong. In particular, the special master
observed that (a) in 2011, the IOM had noted a precaution to receipt of the Tdap vaccine in the

13
   The Vaccine Adverse Event Reporting System (“VAERS”) is a national warning system designed to detect safety
problems in U.S.-licensed vaccines. See About VAERS, VAERS, https://vaers hhs.gov/about html (last visited June
13, 2025). It is managed by both the CDC and the FDA. VAERS monitors and analyzes reports of vaccine related
injuries and side effects from both healthcare professionals and individuals. But it has been observed in the Program
that VAERS data is not particularly probative of causation unless supplemented with other reliable evidence—since
a VAERS report only establishes a temporal, post-vaccination occurrence. See also Vig v. Sec'y of Health & Human
Servs., No. 01–198V, 2013 WL 6596683, at *17 (Fed. Cl. Spec. Mstr. Nov. 14, 2013) (“VAERS is a stocked pond,
containing only reports of adverse events after vaccinations but no data about the number of vaccines administered or
the occurrence of the same adverse event in individuals who have not been vaccinated”).


                                                        23
future if an immunized individual had developed GBS within six weeks of a prior dose, 14 and (b)
this precaution note (along with an acknowledgment of the possibility of encephalopathy in a
seven-day timeframe) had been maintained in subsequent ACIP reports, despite interim findings
that the tetanus-GBS link was not as well-established as previously thought. Mohamad, 2022 WL
711604, at *13–15. From this (and also on the basis of credibility determinations specific to the
experts who had testified in that case), the special master concluded that the first Althen prong was
satisfied. Id. at *7, 15–18.

        I am unpersuaded by the reasoning employed in such cases (independent of the fact that
they do not bind this determination), since they give too much weight to Government policy-
related pronouncements, over actual scientific and medical evidence of putative causation. But
these cases, along with those going the other way, all establish that claims relying on the Tdap
vaccine’s association with GBS are not categorically ruled out—even if the theory they espouse
has also not been fully accepted.

II.      Petitioner Has not Carried Her Burden of Proof

        It is well established that claimants must meet all three Althen prongs—and that a special
master may therefore limit analysis of the strength of a petitioner’s causation showing to only the
prong(s) deemed unsatisfied. Dobrydnev v. Sec’y of Health & Hum. Servs., 566 Fed. Appx. 976,
980 (Fed. Cir. 2014). This claim founders on Petitioner’s inability to demonstrate preponderantly
the third Althen prong—that her GBS onset began in a medically-acceptable timeframe, measured
from the September 4, 2019 date of vaccination. For even if I could find that the Tdap vaccine
“can cause” GBS—and as the discussion above suggests, I strongly lean against such a
conclusion—Petitioner’s GBS began too soon after vaccination to link the two events causally.

        A temporal association alone between a vaccination and subsequent disease “does not
suffice to show a causal link” between the two. Grant v. Sec'y of Health & Human Servs., 956 F.2d
1144, 1148 (Fed. Cir. 1992). Rather, the third Althen prong requires petitioners to establish a
“proximate temporal relationship.” Althen, 418 F.3d at 1281 (emphasis added). To do so, the
claimant must offer “preponderant proof that the onset of symptoms occurred within a timeframe
which, given the medical understanding of the disorder's etiology, it is medically acceptable to
infer causation.” De Bazan, 539 F.3d at 1352. The explanation for what is a “medically acceptable
timeframe” must align with the theory of how the relevant vaccine can cause an injury. Id.

      In the Vaccine Program, onset of an alleged vaccine injury is marked by the “first symptom
or manifestation of onset.” See Section 16(a)(2). As the Federal Circuit stated in Markovich v.


14
  Also of note is the fact that this specified circumstance (advising against receipt of the Tdap vaccine if an individual
previously developed GBS after a prior Tdap dose) is facially distinguishable from the claim that a single dose can
cause GBS for the first time. And it gives weight to the development of GBS after a second dose, while ignoring the
implications of receipt of prior doses without also development of GBS.

                                                           24
Sec'y of Health & Hum. Servs., 477 F.3d 1353, 1357 (Fed. Cir. 2007), there is a difference between
a “symptom” and “manifestation of onset”—but because of the Act’s use of the disjunctive “or,”
either can constitute the start of a disease process (even though a symptom could be nonspecific,
or hard to link to what was later viewed as a full disease). Markovich, 477 F.3d at 1357–59.

        By contrast, the date of diagnosis (which may in turn result from the accumulation of
clinical and testing evidence over time) does not mark the onset of an alleged vaccine injury.
Carson v. Sec'y of Health & Hum. Servs., 727 F.3d 1365, 1369 (Fed. Cir. 2013). Onset may occur
even before the ill individual understands a presenting symptom to be concerning. See Markovich,
477 F.3d at 1357 (“[a] symptom may be indicative of a variety of conditions or ailments, and it
may be difficult for lay persons to appreciate the medical significance of a symptom with regard
to a particular injury”) (emphasis added).

        The medical record in this case best supports the conclusion that Petitioner’s onset most
likely began no later than September 5, 2019—one day post-vaccination. She first sought medical
care two days post-vaccination, complaining of symptoms that could be deemed in isolation to be
nonspecific—but which (in hindsight) appear likely associated with her later diagnosis. Ex. 12 at
10–11. She later expressly told treaters she had experienced sudden, intense back pain on
September 5th, plus leg weakness—and Dr. Brier persuasively interpreted that to be GBS-related.
Ex. 28 at 73–74; Brier Rep. at 3, 6–7. She also reported the same onset date for pain at a pain
management treatment visit around this time. Ex. 10 at 16. And Petitioner consistently reported to
treaters later on that her issues began around the time she was vaccinated. See, e.g., Ex. 29 at 6
(September 13, 2019 EMS treatment record); Ex. 12 at 137 (mid-September hospitalization
record). While Petitioner has offered witness statements attempting to challenge this temporal
sequence (see, e.g., Ex. 63 (Supplemental Affidavit, dated Aug. 9, 2024 (ECF No. 40-15)), the
records themselves are strong and reliable proof that deserve greater weight in my analysis.

        Further, Respondent has established that complaints of back pain (in conjunction with the
other symptoms complained of at the same time) would likely reflect the start of GBS. See Opp.
at 16–17. This conclusion has independent scientific/medical support. See B. Wakerley & N. Yuki,
Mimics and Chameleons in Guillain–Barré and Miller Fisher Syndromes, 15 Pract. Neurol. 90–
99 (2015), filed as Ex. H (ECF No. 44-1) at 91 (stating that “[i]n our experience, many patients
with GBS also report back pain, probably relating to inflammation of nerve roots”); see also
Larson v. Sec’y of Health & Hum. Servs., No. 16-633V, 2023 WL 3765631, at *11, *14 (Fed. Cl.
Spec. Mstr. June 1, 2023) (noting the agreement among experts that lower back pain is common
in GBS and often is a presenting feature of it). Whether or not the Tdap vaccine could have caused
these symptoms, such reporting to contemporaneous treaters of what Petitioner deemed an urgent
medical concern corroborates a close-in-time onset.




                                               25
         It arguably could be concluded from this record that Petitioner’s onset predated vaccination
(in which case there would be no possibility of finding the Tdap vaccine caused her GBS). 15 If
Petitioner’s diplopia (for which she saw treatment the day after vaccination) was, as Dr. Brier
surmised, associated with her GBS, then since she noted on September 5th it had begun two days
earlier, her GBS had actually already manifested before vaccination. Ex. 15 at 5. But more often
than not, such cranial-located symptoms would follow temporally after GBS’s more classic
presenting symptoms of ascending leg and arm weakness, 16 and Petitioner has offered some
credible explanation for this initial treatment visit, arguing that it was associated with chronic
sinusitis. Ex. 63 at ¶¶ 2–3. In any event, there is more record evidence suggesting that the concerns
that lead Petitioner to seek treatment in mid-September began the day after vaccination—and I
base this kind of fact finding on a balancing of the totality of the evidence.

         Dr. Simpson was unsuccessful in his efforts to construe the record to support an onset of
five or more days post-vaccination. His analysis gives too much weight to when treaters were able
to diagnose Petitioner with GBS—even though, as noted above, onset turns on the first
manifestation of a disease, regardless of whether diagnosis was then possible. First Simpson Rep.
at 8. At the same time, Dr. Simpson unpersuasively dismisses Petitioner’s September 5th
complaints of back pain, attributing them to her prior chronic concerns—even though the medical
records do not establish any such complaints in the earlier months of 2019 (and in fact at best show
the last back-related treatment occurred in the winter of 2018. Ex. 10 at 25, 29). 17 While it is true
that Petitioner had a “well-documented” history of back pain (Simpson Supp. Rep. at 1), her prior
issues can be distinguished from what she experienced in September 2019—especially since those
back pain complaints not only were reported in a context of other symptoms, but also since she
went on to be properly diagnosed with GBS within days (thus corroborating an association). The
totality of evidence supports the conclusion that her September 5, 2019 symptoms were likely
GBS-associated.

        Such a short, one-day onset timeframe is not consistent with Petitioner’s causation theory.
Petitioner proposes molecular mimicry as “the most established mechanism” for explaining how
the Tdap vaccine could cause GBS. Br. at 24–25. Molecular mimicry (in which the immune system
cross-reacts against self-tissues, due to similarity between amino acid sequences in a foreign
antigen and self-structures) involves the adaptive immune system—the secondary immune arm,


15
  Of course, claimants can assert that a pre-vaccination injury was exacerbated by a vaccine—but this does not
characterize the cause of action Petitioner has advanced.
16
  This is in fact what appears to have occurred in the Gurwood & Drake case report offered by Dr. Brier. That patient
was hospitalized a week after “an episode of progressive leg weakness, generalized ataxia,” and other symptoms—
with ocular-associated complaints manifesting later. Gurwood & Drake at 540.
17
  In fact, as Respondent observes, there is evidence suggesting that Petitioner’s earlier pain had resolved well before
her September 2019 vaccination. Opp. at 16, citing Ex. 7 at 21. And she did not subsequently complain of it again,
prior to September 5th. Ex. 11 at 57–59; Ex. 8 at 7–8.


                                                         26
which does not immediately respond to a vaccine upon administration. 18 Dennington, 2023 WL
2965239, at *20. Rather, this process takes more than a day to result in the production of antibodies
capable of a cross-reactive, autoimmune attack. Authority filed in this case (including the 2012
IOM Report) is consistent with a longer timeframe for the adaptive response, taking no less than
four days before clinical manifestation caused by antibody production capable of subsequent
autoimmune attack. 2012 IOM Rep. at 57–58; see also Brancheau v. Sec’y of Health & Hum.
Servs., No. 21-1209V, 2024 WL 1619606, at *23–24 (Fed. Cl. Spec. Mstr. Mar. 21, 2024).

        Indeed, even in the context of the Table claim for GBS after receipt of the flu vaccine (the
elements of which are frequently invoked by claimants even when seeking to prove a different
vaccine could also cause GBS—and which are referenced here as well), 19 clinical onset within
three days of vaccination is almost always deemed too fast to be medically acceptable, unless there
are demonstrated unique circumstances relating to the claimant’s own medical history not shown
present herein. A finding of GBS onset occurring within 24 hours of receipt of the flu vaccine
would likely thwart even an off-Table version of such a claim. Rowan v. Sec'y of Health & Human
Servs., No. 17-760V, 2020 WL 2954954 (Fed. Cl. Spec. Mstr. April 28, 2020) (finding that GBS
is known to be mediated by autoantibodies produced via the adaptive immune system, and this
process, if vaccine-induced, likely takes longer than three days to result in symptoms). It is thus
very difficult to conceive of how the acceptable timeframe could be shorter for the Tdap vaccine—
whose analogous wild viral components are far less associated with GBS than a wild flu virus
infection.

       Dr. Simpson attempted to rebut the foregoing by arguing that Petitioner’s prior receipt of
Tdap boosters meant she would likely experience a much faster onset as a result of prior immune
“experience” with the vaccine. See, e.g., Second Supp. Simpson Rep. at 5. But this contention was
not sufficiently substantiated. At most, he offered some reliable evidence about how long the
immune system maintains immunity to Tdap vaccine components. But this does not mean the
response to subsequent exposures would likely result in an antibody-driven disease response
beginning the day after vaccination. It does not lead to the conclusion that each subsequent receipt
of a Tdap booster produces an ever-faster adaptive response—or one that would necessarily be
pathologic. And the four-year gap between when Petitioner received the two Tdap doses (2015 to
2019) is hardly a “close proximity,” as Dr. Simpson proposes. Id.

       I also echo the point made by Dr. Brier about the case reports filed in this case, and what
they suggest about a reasonable timeframe for Tdap vaccine-triggered GBS. Case reports are well

18
  Even if Petitioner herein were to contend that GBS is the product of some other kind of mechanism not involving
the adaptive arm of the immune response, such a contention would swim against the stream of all Program cases
involving GBS—which deem it to most likely be mediated initially by an antibody-driven cross-reactive attack against
self—hence, a process involving the adaptive response to vaccination. See A.T. v. Sec’y of Health & Hum. Servs., No.
20-1716V, 2024 WL 2764822, at *11 (Fed. Cl. Spec. Mstr. Apr. 24, 2024).
19
  See, e.g., Simpson Supp. Rep. at 2 (referencing Table onset period for claim of GBS caused by flu vaccine); Br. at
25–26.

                                                        27
understood in the Vaccine Program to constitute extremely weak causation evidence. Knorr v.
Sec'y of Health & Hum. Servs., No. 15-1169V, 2018 WL 6991548, at *30 (Fed. Cl. Spec. Mstr.
Dec. 7, 2018) (citations omitted). And I have already noted reasons to give certain of them filed in
support of Petitioner’s claim—Pollard & Selby in particular—very little weight, even if they also
involve tetanus-containing vaccines. But setting aside such reasonable qualms, the case reports
offered in this case of GBS occurring after the administration of the Tdap vaccine involved longer
post-vaccination timeframes than what the record supports likely occurred here. See, e.g., Bakshi
& Graves (four days), Newton & Janati (nine days), and Pollard & Selby (ten days at the earliest).
This is consistent with what is known about GBS’s pathogenesis—but not consistent with
Petitioner’s medical history.

                                                 CONCLUSION

       A Program entitlement award is only appropriate for claims supported by preponderant
evidence. Here, Petitioner has not made such a showing. Petitioner is therefore not entitled to
compensation.

       In the absence of a motion for review filed pursuant to RCFC Appendix B, the Clerk of the
Court SHALL ENTER JUDGMENT in accordance with the terms of this Decision. 20

         IT IS SO ORDERED.

                                                                          /s/ Brian H. Corcoran
                                                                          Brian H. Corcoran
                                                                          Chief Special Master




20
  Pursuant to Vaccine Rule 11(a), the parties may expedite entry of judgment if (jointly or separately) they file notices
renouncing their right to seek review.

                                                          28