Court Opinion

ID: 6340981
Source: CourtListenerOpinion
Date Created: 2022-05-16 13:01:19.883329+00
Date Added: 2024-06-11T09:19:50.390006
License: Public Domain

In the United States Court of Federal Claims

    DONALD WINKLER,

                     Petitioner,
                                                          No. 18-203V
    v.                                                    (Filed: May 13, 2022)*
                                                          *Opinion originally filed under
    SECRETARY OF HEALTH AND HUMAN
                                                           seal on April 28, 2022
    SERVICES,

                    Respondent.

Michael Patrick Milmoe, Law Offices of Leah V. Durant, PLLC, Washington, DC, for
Petitioner.

Ryan Daniel Pyles, U.S. Department of Justice, Civil Division, Vaccine/Torts Branch,
Washington, DC, with whom were Gabrielle M. Fielding, Assistant Director, Heather L.
Pearlman, Deputy Director, C. Salvatore D’Alessio, Acting Director, and Brian M. Boynton,
Assistant Attorney General, for Respondent.

                                    OPINION AND ORDER

LERNER, Judge.

        Pending before the Court is Donald Winkler’s (“Petitioner” or “Mr. Winkler”) Motion for
Review of the Special Master’s Decision denying him compensation under the National
Childhood Vaccine Injury Act of 1986, 42 U.S.C. §§ 300a-1 to -34 (“the Vaccine Act”). 1
Petitioner argues that the tetanus/diphtheria (“Tdap”) vaccine he received on April 26, 2017,
caused him to develop Guillain-Barré Syndrome (“GBS”). 2 The Special Master found that
Petitioner was not entitled to compensation because he failed to establish by a preponderance of

1
  This Opinion will capitalize the first letter of the words “Petitioner” and “Respondent” to refer
to the specific litigants in this case while keeping those letters in lower case when referring to
generic petitioners and respondents. To avoid excessive use of brackets, this Opinion applies the
same style within quoted material without further noting these alterations.
2
  GBS is a “rapidly progressive ascending motor neuron paralysis of unknown etiology,
frequently seen after an enteric or respiratory infection.” Simanski v. Sec’y of Health & Hum.
Servs., 115 Fed. Cl. 407, 411 n.13 (2014) (quoting Dorland’s Illustrated Medical Dictionary
1832 (32d ed. 2012)), aff’d 601 F. App’x 982 (Fed. Cir. 2015). “It begins with paresthesias of
the feet, followed by flaccid paralysis of the entire lower limbs, ascending to the trunk, upper
limbs, and face.” Id.
the evidence a logical sequence of cause and effect showing that the vaccination was the reason
for his injury. In his Motion for Review, Petitioner contends that the Special Master’s Decision
dismissing his Petition was arbitrary, capricious, an abuse of discretion, and not in accordance
with law. While the Court is sympathetic to Mr. Winkler’s plight, for the reasons set forth below
the Court finds that the Special Master acted within her discretion. Accordingly, the Motion for
Review is DENIED and the Special Master’s Decision is AFFIRMED.

I.     Background

       A.      Factual Background

        The Special Master’s Decision contains a thorough and accurate account of this case’s
background facts, the most salient of which are as follows. See Decision (“Dec.”) 4–11, ECF
No. 61. Mr. Winkler was 66 years old and in generally good health when he received the Tdap
vaccine on April 26, 2017, after stepping on a wire and receiving a painful wound. Pet. ¶ 1, ECF
No. 1; Pet’r’s Ex. (“Pet. Ex.”) 3 at 9, ECF No. 7-3. Two days later, on April 28, 2017, Mr.
Winkler visited a medical clinic and complained of “itchy, tingling legs,” insomnia, and frequent
urination as well as left knee pain. Pet. ¶ 2; Pet. Ex. 5 at 4, ECF No. 7-5. The physician found
Mr. Winkler’s leg symptoms most likely related to varicose veins and recommended that he see a
specialist. Pet. ¶ 2; Pet. Ex. 5 at 6. He was given a pneumococcal conjugate (“Prevnar”)
vaccination during his examination. Pet. ¶ 2.

         On May 3, 2017, Mr. Winkler returned to the clinic for “labs, fatigue[], & bloody stools,”
and presented with complaints of fatigue, aches, headaches, diarrhea, and frequent urination.
Pet. ¶ 3 (quoting Pet. Ex. 5 at 2). He also reported chills, feeling feverish, sinus congestion, and
a bloody nose. Pet. Ex. 5 at 2. Mr. Winkler reported abdominal pain but no dyspepsia,
heartburn, nausea, vomiting, or constipation. He reported diarrhea three to six times daily and
said there may have been melena or bright red blood with the diarrhea. Id. at 2. The doctor’s
assessment was fatigue, myalgia, urinary frequency, diarrhea, and a gastrointestinal (“GI”)
illness, specifically gastroenteritis. Id. at 3.

       On May 11, 2017, Mr. Winkler visited an emergency room (“ER”), complaining of “2
weeks of progressively worsening weakness.” Pet. Ex. 3 at 26. He reported instability, trouble
standing, limping on his left leg, and difficulty using his hands. Id. at 7. Dr. Bruce A. Daniel in
the ER documented that Mr. Winkler’s symptoms “started after a [Prevnar] vaccine and a bout of
diarrhea, which [Mr. Winkler] had about the same time 2 weeks ago.” Pet. Ex. 3 at 26. Dr.
Daniel opined that Mr. Winkler had GBS. Pet. ¶ 4. Mr. Winkler was admitted to the hospital.
Id.

       On May 12, 2017, after more testing, a lumbar puncture confirmed a GBS diagnosis. Id.
Dr. Mitchell Melling assessed him with the acute inflammatory demyelinating polyneuropathy
(“AIDP”) variety of GBS. Pet. Ex. 3 at 15. Mr. Winkler was discharged on May 16, 2017, with
a diagnosis of GBS and “proximal muscle weakness.” Pet. ¶ 7 (quoting Pet. Ex. 3 at 13). He
was advised to follow up with Dr. James D. White, who had collaborated in his in-patient
treatment, within one week. Id.

                                                 2
        Mr. Winkler saw Dr. White for a follow-up on May 23, 2017, at which time he reported
some improvement but continued weakness, pain, and fatigue. Pet ¶ 8. Mr. Winkler stated that
he believed his symptoms had started around May 6, 2017, or slightly earlier. Pet. Ex. 6 at 29,
ECF No. 7-6. Dr. White noted that “the patient has symptoms strongly suggestive of AIDP”
with a differential diagnosis of chronic inflammatory demyelinating polyneuropathy (“CIDP”). 3
Pet. ¶ 8. He was advised to follow up on June 2, 2017. Id.

        On June 2, 2017, Mr. Winkler visited Dr. White for an electro-neuro diagnostic study.
Pet. ¶ 9. Dr. White noted that “[a]bout 4 weeks ago, [Mr. Winkler] developed diarrhea,” and “3
weeks ago he developed weakness and was diagnosed with [GBS] (mostly likely AIDP).” Pet.
Ex. 6 at 13. He noted that Mr. Winkler’s medical history was “quite classic for [GBS]; he had a
bout of diarrhea and one week later experienced significant weakness with suppressed reflexes.”
Id. at 14. Dr. White considered whether Mr. Winkler might have had acute motor axonal
neuropathy (“AMAN”) or acute motor-sensory axonal neuropathy (“AMSAN”)—which are two
sub-types of GBS—but decided that these types were less likely than GBS “of the AIDP
variety.” Id. at 14–15. However, he also wrote that the “possibility of CIDP cannot entirely be
ruled out.” Id. at 15.

        Mr. Winkler then began a series of follow-up medical appointments. He visited Dr.
White on June 14, July 12, and August 9, 2017. Pet. ¶ 10 (citing Pet. Ex. 6 at 3, 6–7, 11).
Although his condition improved, Mr. Winkler remained “probably weak relative to his prior
condition.” Id. (quoting Pet. Ex. 6 at 3). Mr. Winkler also began a course of physical therapy
treatments on August 18, 2017. Id. ¶ 11 (citing Pet. Ex. 2 at 8, ECF No. 7-2). This continued for
five sessions, with the last occurring on September 20, 2017. Pet. Ex. 2 at 9. He reported some
improvement by this last session. Id. at 4.

        Mr. Winkler saw Dr. White again on September 11 and December 13, 2017. Pet. Ex. 6
at 1–2, 76–77. Dr. White noted that Mr. Winkler’s lower body strength was improving, although
his upper extremity strength was not satisfactory. Id. at 76. Dr. White’s diagnostic impression
remained GBS, most likely AIDP. Id. Mr. Winkler also saw Dr. White on January 10, 2018. Id.
at 59–64. Dr. White documented steady improvement despite ongoing weakness, primarily in
the upper extremities. Id. at 59. He opined that Mr. Winkler’s persistent weakness was
“secondary to the axonal nature of his condition” and noted that Mr. Winkler had been
improving. Id. Mr. Winkler returned to Dr. White on January 29, 2018, complaining of pain and
fatigue. Id. at 53–54. In Dr. White’s evaluation, Mr. Winkler’s clinical course was “most
strongly reminiscent of AMSAN.” Id. at 54.

3
  CIDP is a “slowly progressive, autoimmune type of demyelinating polyneuropathy
characterized by progressive weakness and impaired sensory function in the limbs and
enlargement of the peripheral nerves, usually with elevated protein in the cerebrospinal fluid”
that “occurs most commonly in young adults and is related to Guillain–Barré syndrome.”
Semanski, 115 Fed. Cl. at 412 n.15 (quoting Dorland’s Illustrated Medical Dictionary 1491 (32d
ed. 2012)).

                                               3
       On February 13, 2018, Mr. Winkler executed an affidavit documenting his experience.
See Pet. Ex. 7, ECF No. 7-7. As of that date, he still had difficulty engaging in certain activities
and suffered aches, numbness, and pain. Id. ¶ 4.

       B.      Procedural Background

               1.      Proceedings before the Special Master

        Mr. Winkler filed his Petition in this case on February 9, 2018. See Pet. On
February 15, 2019, after reviewing the Petition, Respondent, the Secretary of Health and Human
Services (“Respondent” or “the Government”), recommended against compensation. See
Resp’t’s Rule 4(c) Report, ECF No. 14. In an April 2, 2020 order, the Special Master
encouraged the parties to attempt settlement. See Order at 2, ECF No. 31. On March 24, 2021,
Petitioner filed a motion for a ruling on the record. See Mot. for Ruling on the R., ECF No. 49.
Further briefing occurred through July 23, 2021, and on December 10, 2021, the Special Master
issued a decision dismissing the Petition. See Dec. at 34. Mr. Winkler filed a motion for review
and accompanying brief on January 10, 2022. See Mot. for Rev., ECF No. 62; Memo. of Objs.
(“Pet’r’s Br.”), ECF No. 63. The Government filed a response on February 9, 2022. See
Resp’t’s Resp. to Mot. for Rev. (“Resp.”), ECF No. 65.

               2.      Expert Opinions

        Both parties submitted expert reports for the Special Master’s consideration. Petitioner
submitted a report by Dr. John R. Rinker, a board-certified neurologist with a subspeciality in
neuroimmunology and Associate Professor of Neurology at the University of Alabama,
Birmingham, who opined that Mr. Winkler’s vaccination most likely caused his GBS. See Pet.
Ex. 9, ECF No. 19-1. Respondent submitted expert reports by Dr. J. Lindsay Whitton and Dr.
Vinay Chaudhry. See Resp’t’s Ex. (“Resp. Ex.”) A, ECF No. 27-1; Resp. Ex. C, ECF No. 28-1.
Dr. Whitton is a professor in the Department of Immunology and Microbiology at Scripps
Research Institute in California, and Dr. Chaudhry is a board-certified neurology professor at
Johns Hopkins University School of Medicine and the Director of the Neurology EMG
Laboratory at Johns Hopkins Hospital. See Resp. Ex. A at 1; Resp. Ex. C at 1. Both professors
concluded that it was more likely that a GI infection had caused the GBS, and that the most
likely source of the infection was a bacteria called Campylobacter jejuni (“C. jejuni”). See Resp.
Ex. A; Resp. Ex. C.

                       a. Dr. Rinker’s Report

       Dr. Rinker opined that the vaccination likely caused Mr. Winkler’s GBS through a
process called “molecular mimicry.” Pet. Ex. 9 at 4. He explained that this phenomenon occurs
when the immune system fails to distinguish between foreign cells and the body’s own cells, and
“because of the structural resemblance, antibodies and auto-reactive T cells not only destroy the
invading pathogen but can react with host tissues as well.” Id. (quoting Pet. Ex. 37 at 3, ECF
No. 55-1). He stated that “[a]n estimated 2/3 of GBS cases are preceded by an illness within 4
weeks before the onset of neurological symptoms,” and that “[r]espiratory illnesses are the most
common antecedent infections while diarrheal illnesses (esp. C. jejuni) are the next most

                                                  4
common.” Id. at 3 (citation omitted). He added that “[a]nother potential immunological trigger
for GBS is vaccination.” Id.

        Dr. Rinker explained his view that there is a causal relationship between vaccination and
GBS. He pointed to a 1976 vaccination campaign against swine influenza, which resulted in
vaccinated individuals reporting GBS at seven times the rate reported in unvaccinated
individuals. Id. at 3. Dr. Rinker claimed that “[s]ubsequent epidemiological links between
vaccination and GBS have found an excess GBS risk of 1.6 excess cases of GBS per 1 million
vaccine recipients, without a strong signal coming from any specific vaccine types.” Id. (citation
omitted). He also pointed to four individual case reports of GBS after patients received tetanus-
toxoid-containing vaccines, see id. at 5, and noted that these case studies led to a 1994 Institute
of Medicine (“IOM”) report and a 1996 Centers for Disease Control and Prevention (“CDC”)
report that both “caution[ed] against a possible causal relationship between tetanus toxoid and
GBS,” id. at 5 (first citing Pet. Ex. 24, ECF No. 23-15; and then citing CDC, Update: Vaccine
Side Effects, Adverse Reactions, Contraindications, and Precautions Recommendations of the
Advisory Committee on Immunization Practices (ACIP), 45 Morbidity and Mortality Weekly
Report: Recommendations and Reports RR-12 (1996)). He also referred to a report drawing
from the Vaccine Adverse Event Reporting System concluding that vaccines other than influenza
can be associated with GBS. Id.

        Dr. Rinker noted that “C jejuni is the most common infectious trigger of GBS,” but that
“less than 0.1% of C jejuni infections result in a case of GBS.” Id. In his view, “the rarity with
which GBS occurs even following exposures to known triggers of the condition, should allow for
the possibility that sporadic cases of GBS may occur following other immunological stimuli.”
Id. He stated that “[i]n Mr. Winkler’s case, it is not possible to distinguish whether vaccination
or the diarrheal illness alone was responsible for his GBS, or whether the two immunological
stimuli worked in concert to provoke the immune response.” Id. at 6. In Dr. Rinker’s view,
“there is insufficient evidence to claim that the illness was a more likely cause of GBS than the
vaccine” because Mr. Winkler’s treating physicians did not document any tests that could
identify an organism as the cause of his GI illness and because it is possible that the illness was
not infectious at all. Id.

        Dr. Rinker concluded that the Tdap vaccine was the most likely cause of Mr. Winkler’s
GBS. Id. at 7. Citing a study of GBS cases from 1996–2004, Dr. Rinker claimed that median
latencies between infection and GBS were 15 days for influenza, 10 days for C. jejuni, and 6.5
days for cases where infection was suspected but not identified. Id. at 5. The ranges for these
latencies were 7–21 days, 5–12 days, and 4–8 days, respectively. Id. Dr. Rinker observed that
Mr. Winkler’s GBS symptoms began 9–10 days after his vaccination and 4–5 days after his
diarrheal illness. Id. at 7. Based on this timing, he concluded that the evidence suggested the
vaccination was the more likely cause of the GBS. Id. at 7.

                      b. Dr. Whitton’s Report

        In contrast, Dr. Whitton opined that Mr. Winkler’s GI illness was the more likely cause
of his GBS. He explained that approximately two-thirds of GBS cases are preceded by signs or
symptoms of an infection—often of the respiratory or GI tracts—and that for GI infections, there

                                                5
is a strong association between C. jejuni and GBS. Resp. Ex. A at 4. He stated that it is common
for GBS to appear within a few days after the onset of symptoms because infectious diseases
have an incubation period and the body’s adaptive immune response begins to react to infection
before GI symptoms appear. Id. Unlike these diseases, vaccinations do not have an incubation
period, which led Dr. Whitton to determine that “a 2-day interval between diarrheal disease and
GBS may be acceptable . . . but the same 2-day interval after a vaccination would not be
similarly acceptable” as an explanation. Id. at 5. In his opinion, given the incubation period of
C. jejuni, the infection that caused Mr. Winkler’s diarrhea likely set in on or around the day that
he received the vaccination. Id. at 6. He concluded that, factoring in this incubation period, Mr.
Winkler’s case likely fell well within the latency periods between GI infection and GBS cited in
Dr. Rinker’s report. Id. at 9–10.

         Dr. Whitton challenged any causal connection between the Tdap vaccine and GBS. He
observed that although the tetanus toxoid vaccine was developed in 1924 and has been in
widespread use since the early 1940s, Dr. Rinker’s report only cited to four case studies of GBS
preceded by such a vaccine, only one of which concerned Tdap, the vaccine that Mr. Winkler
received. Id. at 6 (citing Pet. Ex. 9, at 5). Dr. Rinker had referred to a patient mentioned in the
1994 IOM report as having developed GBS following a tetanus toxoid vaccination, but Dr.
Whitton pointed out that the 2012 revision to the IOM report re-diagnosed the patient in question
as having CIDP rather than GBS and found no link between that condition and the vaccination.
Id. at 8. He added that the Tdap vaccine was not licensed until 2005, so the 1994 report on
which Dr. Rinker relied did not address it. Id. Dr. Whitton also cited several reports finding no
association between GBS and vaccines (although some of these papers concerned vaccines other
than Tdap). See id. at 6–7.

        In addressing Dr. Rinker’s assertion that the rarity of post-vaccination GBS suggests a
causal relationship between the vaccine and Mr. Winkler’s illness, Dr. Whitton considered the
incidence of Tdap vaccination and GBS in the population, noting that a certain amount of
coincidental post-vaccination GBS is to be expected. See id. at 9. He explained that if there
were an individual whose GBS was caused by the Tdap vaccine—assuming such a causal
relationship could even exist—the epidemiological data would not treat that person differently
from the larger number of coincidental cases, meaning that for any such individual, the data
would actually suggest that their GBS was more likely than not unrelated to the vaccine. Id.
at 11–12.

        Ultimately, Dr. Whitton said, GI infection “is known to incite GBS; indeed, it is one of its
most frequent triggers,” while, “[i]n contrast, . . . Tdap is not known to cause GBS (and studies
indicate that it does not do so).” Id. at 11. He concluded that “these straightforward
considerations tip the scales of probability extraordinarily heavily in favor of the known cause—
GI infection.” Id.

                       c. Dr. Chaudhry’s Report

        Dr. Chaudhry also noted that antecedent infection precedes two-thirds of GBS cases.
Resp. Ex. C at 10. He stated that the “presence of [Mr. Winkler’s] diarrheal illness [w]as one of
the factors in making the diagnosis of GBS as noted by Dr. White, Dr. Melling, and other

                                                 6
physicians.” Id. at 11. He also observed that while C. jejuni is the predominant infection, found
in 25–50 percent of adult patients, several other infections are similarly associated with GBS. Id.
Dr. Chaudhry added that while both AIDP and AMAN are associated with C. jejuni infection,
AMAN is more likely. Id.

        Dr. Chaudhry’s review of the medical record led him to conclude that Mr. Winkler “had
more features for the AMAN subtype than the AIDP subtype of GBS.” Id. at 10. In particular,
he noted that Mr. Winkler had hyperreflexia and suffered an antecedent diarrheal illness, and that
Mr. Winkler’s follow-up electromyography study showed axonal damage, all of which would
suggest AMAN rather than AIDP. Id. at 10–11. He also noted that Mr. Winkler did not have
indications of AIDP, such as cranial nerve or sensory involvement, autonomic dysfunction, or
significant change in his sensory or motor nerves. Id. Dr. Chaudhry observed that, although Mr.
Winkler’s diagnosing physician, Dr. White, raised the possibility of AMAN before concluding
that sensory involvement ruled it out as a diagnosis, Dr. White did not refer to any such sensory
involvement in his clinical or electrophysiological findings. Id. at 11.

        Dr. Chaudhry considered reports and studies regarding the possibility of an association
between either the Prevnar or Tdap vaccine and GBS and found no likely association. Id.
at 11–13. Regarding Tdap in particular, he explained that the IOM considered epidemiological
studies as well as publications assessing mechanistic evidence and the IOM report itself
concluded that evidence was insufficient to determine an association. Id. at 12. In fact, the
“[n]umber of GBS cases after administration of tetanus toxoid vaccines in both children and
adults is not greater than the number expected by chance alone.” Id. at 13.

        Dr. Chaudhry also addressed shortcomings in Dr. Rinker’s report. Like Dr. Whitton, he
considered Dr. Rinker’s focus on instances of other vaccines being associated with GBS “not [to
be] appropriate.” Id. at 14. He noted several places in which Dr. Rinker appeared to have
misquoted or misinterpreted the medical record. See, e.g., id. at 13 (noting that “Dr. Rinker
mentions that Mr. Winkler had multifocal demyelinating neuropathy” but that “[t]his was not the
case”). Similar to Dr. Whitton, Dr. Chaudhry also took issue with Dr. Rinker’s reliance on the
CDC’s 1996 report, rather than a follow-up report that found only one case of GBS within six
weeks of Tdap vaccination, when two such cases were expected by chance alone. Id. at 14. Dr.
Chaudhry also joined Dr. Whitton in dismissing a study that the 1994 and 1996 reports
examined—and on which Dr. Rinker relied—because the IOM’s revised report from 2012 re-
diagnosed the subject of the study as suffering from CIDP rather than GBS. Id.

        Regarding the timing issue, Dr. Chaudhry disagreed with Dr. Rinker’s assessment that
the time between diarrheal illness and GBS is four to five days. Instead, like Dr. Whitton, he
pointed to studies showing a wide array of times between the onset of diarrheal illness and
subsequent onset of weakness. Id. In Dr. Chaudhry’s view, “[e]xcluding a well-known and
established cause of GBS on an arbitrarily [sic] basis of time for which there is no support, is not
rational.” Id. at 15.

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                       d. Supplemental Reports

         Dr. Rinker submitted a supplemental report in which he addressed Dr. Chaudhry’s report.
Pet. Ex. 31, ECF No. 39-1. In this short response, he argued that C. jejuni causes only a small
fraction of known instances of gastroenteritis, the vast majority of which do not result in GBS.
Id. at 1. He claimed that norovirus is a more likely cause of gastroenteritis and stated that “while
Mr. Winkler may have been affected by C. jejuni in the days leading up to the onset of his GBS,
there is no confirmatory laboratory evidence to support this possibility as the organism was never
identified, despite testing.” Id. He also noted that diarrhea is a possible adverse effect of the
Tdap vaccine. Id. at 1–2. Dr. Rinker opined that “there is insufficient evidence to claim that Mr.
Winkler’s diarrheal illness was the immunological trigger which initiated his GBS.” Id. at 2.
Based on his view that “C. jejuni is an uncommon cause of gastroenteritis, and there is nothing in
the record that links C. jejuni to Mr. Winkler’s GBS,” Dr. Rinker concluded that “the mere
presence of diarrhea before the onset of GBS, especially when C. jejuni was never identified,
provides an unlikely cause of Mr. Winkler’s GBS in comparison to the Tdap vaccination.” Id.
at 2.

        Dr. Chaudhry submitted a supplemental report addressing Dr. Rinker’s response. Resp.
Ex. E, ECF No. 42-1. He cited reports by the CDC and World Health Organization, as well as
additional studies finding that infection with C. jejuni is one of the most common causes of
gastroenteritis. Id. at 1–2. He disputed Dr. Rinker’s suggestion that Mr. Winkler’s infection
might have been caused by norovirus, arguing that “[b]loody stools are not a feature of norovirus
infection but are a feature of bacterial gastroenteritis” and that there was no evidence Mr.
Winkler came into contact with any person infected with norovirus. Id. at 2. Dr. Chaudhry cited
several publications to demonstrate that infection with C. jejuni frequently precedes GBS, with
25–40 percent of GBS patients worldwide suffering from such an infection 1–3 weeks prior to
the illness. Id. at 2–3.

        In response to Dr. Rinker’s assertion that no C. jejuni infection was found despite testing,
Dr. Chaudhry stated that he did not see any such testing in Mr. Winkler’s record. Id. at 3.
However, he did not give the absence of testing much weight because a “majority of incident
cases of C. jejuni infection are likely undiagnosed but an antecedent history of diarrhea followed
by development of acute motor form of GBS and the known molecular mimicry are highly
suggestive if not indicative of C. jejuni causing GBS.” Id. at 3 (citation omitted). Ultimately,
Dr. Chaudhry concluded that “[i]t is more likely than not that [Mr. Winkler’s] GBS was caused
by C. jejuni associated diarrhea, a proven association, rather than caused by Tdap vaccine, an
unproven association.” Id. at 4.

       C.      The Special Master’s Decision

        On December 10, 2021, the Special Master issued a decision denying Petitioner
compensation under the Vaccine Act. Dec. at 34. The Special Master concluded, based on her
review of the expert testimony and medical records, that “Petitioner has not established by
preponderant evidence that his vaccinations caused his GBS.” Id. The Special Master explained
that Petitioner was required to prove by a preponderance of the evidence that the vaccine caused
the injury. Id. at 28 (citing Moberly v. Sec’y of Health & Hum. Servs., 592 F.3d 1315, 1322 n.2

                                                 8
(Fed. Cir. 2010)). Petitioner was not required to demonstrate medical certainty or to make a
specific evidentiary showing but did have to “prove that the vaccine was ‘not only [the] but-for
cause of the injury but also a substantial factor in bringing about the injury.’” Id. (quoting
Moberly, 592 F.3d at 1321) (alteration in original). The framework for establishing causation is
laid out in Althen v. Secretary of Health and Human Services, 418 F.3d 1274, 1278 (Fed. Cir.
2005). In order to show causation-in-fact, a petitioner must provide “(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 a proximate
temporal relationship between vaccination and injury.” Id.

         The Special Master explained that if a petitioner satisfies this burden, they are entitled to
compensation “unless Respondent can prove, by a preponderance of the evidence, that the
vaccinee’s injury is ‘due to factors unrelated to the administration of the vaccine.’” Dec.
at 28–29 (quoting 42 U.S.C. § 300aa-13(a)(1)(B)). But “[r]egardless of whether the burden ever
shifts to the respondent, the special master may consider the evidence presented by the
respondent in determining whether the petitioner has established a prima facie case.” Id. at 29
(quoting Flores v. Sec’y of Health & Hum. Servs., 115 Fed. Cl. 157, 162–63 (2014)).

         Here, the Special Master applied the three Althen prongs to Petitioner’s case. Regarding
the first prong, the Special Master stated that “the experts agree that molecular mimicry is not a
disputed theory as it relates to GBS.” Id. at 30. However, she stated that while they “did not
dispute that a GI illness can cause GBS,” they did “dispute whether the vaccines at issue here can
cause GBS.” Id. Ultimately, the Special Master did not reach a conclusion as to whether
Petitioner met his burden under Althen prong one. Instead, she decided that “[d]ue to the facts
and circumstances of this case, specifically the fact that Petitioner had a preceding GI illness
prior to his GBS, the [Special Master’s] determination as to causation turns on an analysis of
Althen Prong Two.” Id. The Special Master concluded that, “[a]ssuming that Petitioner has
proven a sound and reliable causal mechanism under Althen Prong One, . . . Petitioner did not
provide preponderant evidence of a logical sequence of cause and effect under the facts of this
case.” Id.

        In assessing the claim under Althen prong two, the Special Master gave “some weight” to
the opinions and views of Mr. Winkler’s treating physicians. Id. at 31 (first citing Andreu v.
Sec’y of Health & Hum. Servs., 569. F.3d 1367, 1367 (Fed. Cir. 2009); and then citing Capizzano
v. Sec’y of Health & Hum. Servs., 440 F.3d 1317, 1326 (Fed. Cir. 2006)). She noted that “Dr.
Melling did not associate Petitioner’s vaccinations with his GBS,” id., and observed that Dr.
White, who conducted follow-up appointments with Mr. Winkler, “found [Mr. Winkler’s]
medical history ‘quite classic for [GBS]; he had a bout of diarrhea and one week later
experienced significant weakness with suppressed reflexes,’” id. (quoting Pet. Ex. 6 at 14).

        The Special Master also considered the experts’ analysis of causation. She observed that
while the record did not show any testing was completed to confirm whether Mr. Winkler had a
specific infection, such as C. jejuni, Respondent’s experts considered a lack of testing to be
common with GBS cases. Id. at 32. She gave weight to Dr. Chaudhry’s assertions that Mr.
Winkler’s symptoms were consistent with typical symptoms of C. jejuni infection and that the
treating physicians had considered his history of diarrhea relevant to treatment and diagnosis. Id.

                                                  9
        The Special Master explained that she found Dr. Rinker’s reasoning regarding causation
unpersuasive. Id. She stated that the medical literature he cited is consistent with the
Respondent’s experts’ findings, particularly regarding the incubation period for C. jejuni
infections, which “would place the date of infection before or approximately the date of
Petitioner’s vaccination.” Id. The Special Master concluded that the temporal association
between the vaccination and GBS onset thus did not favor vaccination as the more likely cause.
Id. She also noted that, although Dr. Rinker argues that “the mere presence of diarrhea before
the onset of GBS . . . provides an unlikely cause” of the illness in comparison to the vaccine, id.
(quoting Pet. Ex. 31 at 2), “[t]his argument does not explain how the Tdap vaccine is the more
likely cause of Petitioner’s GBS,” id.

        The Special Master stated that she was “not persuaded by Petitioner’s arguments, given
Petitioner’s clinical course, treating physician statements, and the experts’ opinions and
supporting medical literature.” Id. She “acknowledge[d] that Petitioner is not required to
eliminate other potential causes in order to be entitled to compensation,” but found it “reasonable
to consider ‘evidence of other possible sources of injury’. . . in determining ‘whether a prima
facie showing has been made that the vaccine was a substantial factor in causing the injury in
question.’” Id. at 32–33 (quoting Stone ex rel. Stone v. Sec’y of Health & Hum. Servs., 676
F.3d 1373, 1379 (Fed. Cir. 2012)). The Special Master decided that, “[i]n this case, ‘the
presence of multiple potential causative agents makes it difficult to attribute “but for” causation
to the vaccination,’” and that, as such, “Petitioner failed to prove that the Tdap and/or Prevnar
vaccines were the ‘but for’ cause of Petitioner’s GBS.” Id. at 33 (quoting Pafford v. Sec’y of
Health & Hum. Servs., 451 F.3d 1352, 1358–59 (Fed. Cir. 2006)).

       Regarding Althen prong three, the Special Master’s examination of the record
demonstrated that “Petitioner’s GBS onset of May 5 or 6, 2017 was 9–10 days after Petitioner’s
Tdap vaccination, 7–8 days after Petitioner’s Prevnar vaccination, and 5–6 days after his
diarrheal illness onset.” Id. at 34. She determined that “[a]ll of these intervals are appropriate”
and that Petitioner had satisfied the third Althen prong. Id.

       D.       The Motion for Review

        Petitioner filed his Motion for Review and accompanying Memorandum of Objections.
Mot. for Rev.; Pet’r’s Br. He argues that the Special Master erred by applying an incorrect
burden of proof, Pet’r’s Br. at 11, 20, and by considering irrelevant or unreliable evidence, id. at
13–20. In particular, he argues that the Special Master erred in considering evidence concerning
a C. jejuni infection when no such infection was ever proven to have occurred and in
inappropriately considering statistical evidence. Id. at 16, 18–19. He also challenges the way in
which the Special Master weighed the evidence. Id. at 17.

II.    Legal Standards

        The Vaccine Act created the National Vaccine Injury Compensation Program, which
provides compensation for vaccine-related injuries or deaths. 42 U.S.C. § 300aa. This Court has
jurisdiction to review the decisions of a special master in a Vaccine Act case upon a motion from
the petitioner. 42 U.S.C. § 300aa-12(e)(2). The Court applies three distinct standards of review

                                                 10
in Vaccine Act cases: whether findings of fact are “arbitrary and capricious,” whether
conclusions of law are “not in accordance with law,” and whether discretionary rulings are an
“abuse of discretion.” Masias v. Sec’y of Health & Hum. Servs., 634 F.3d 1283, 1287–88
(Fed. Cir. 2011); Munn v. Sec’y of Health & Hum. Servs., 970 F.2d 863, 870 n. 10 (Fed. Cir.
1992); see 42 U.S.C § 300aa-12(e)(2)(B). However, the Court does not “reweigh the factual
evidence,” “assess whether the special master correctly evaluated the evidence,” or “examine the
probative value of the evidence or the credibility of the witnesses.” Lampe v. Sec’y of Health &
Hum. Servs., 219 F.3d 1357, 1360 (Fed. Cir. 2000) (quoting Munn, 970 F.2d at 871). If a special
master “has considered the relevant evidence of record, drawn plausible inferences and
articulated a rational basis for the decision,” then “reversible error is extremely difficult to
demonstrate.” Id. at 1360 (quoting Hines ex rel. Sevier v. Sec’y of Health & Hum. Servs., 940
F.2d 1518, 1528 (Fed. Cir. 1991)).

        To be compensated, a petitioner must prove they have an injury that was caused by a
vaccine. There are two types of claims under the Vaccine Act: claims based on injuries listed in
the Vaccine Injury Table (“Table claims”) and claims based on injuries not listed in the Table
(“off-Table claims”). See 42 U.S.C.§ 300aa-14; Pafford v. Sec’y of Health & Human Servs., 451
F.3d 1352, 1355 (Fed. Cir. 2006) (describing Table and off-Table cases). In a Table claim, a
petitioner is granted a presumption of causation if they show that they received a vaccine listed
in the Table, suffered a corresponding injury listed in the Table, and the injury occurred within
the prescribed time limitations. 42 U.S.C.§ 300aa-14; see Andreu ex rel. Andreu v. Sec’y of
Health & Hum. Servs., 569 F.3d 1367, 1374 (Fed. Cir. 2009) (describing Table cases). This
presumption satisfies the petitioner’s burden to establish a prima facie case for compensation.
Andreu, 569 F.3d at 1374.

        In an off-Table case, a petitioner who received a vaccine listed in the Table but suffered
an injury not listed in the Table must prove causation by a preponderance of the evidence
without the benefit of any favorable presumption. See Moberly, 592 F.3d at 1321 (describing
off-Table cases). To prove causation in an off-Table case, a petitioner must show that the injury
“was caused by a vaccine” listed in the Table. 42 U.S.C. § 300aa-11(c)(1)(C)(ii)(I). The Federal
Circuit uses the Althen test to evaluate causation in vaccine injury cases. A petitioner must:

           show by preponderant evidence that the vaccination brought about her
           injury by providing: (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 a proximate temporal relationship between vaccination and
           injury.

Althen, 418 F.3d at1278.

        Once the petitioner satisfies their burden, either through a favorable presumption in a
Table case or through satisfying the Althen test in an off-Table case, they are “entitled to recover
unless [the respondent] shows, also by a preponderance of evidence, that the injury was in fact
caused by factors unrelated to the vaccine.” Walther v. Sec’y of Health & Hum. Servs., 485 F.3d
1146, 1151–52 (Fed. Cir. 2007) (quoting Whitecotton v. Sec’y of Health & Hum. Servs., 17 F.3d

                                                 11
374, 376 (Fed. Cir. 1994), rev’d on other grounds sub nom. Shalala v. Whitecotton, 514 U.S. 268
(1995)) (citing Knudsen v. Sec’y of Health & Hum. Servs., 35 F.3d 543, 547 (1994)).

III.   Discussion

       A.      Whether the Special Master Applied the Appropriate Burden of Proof

        Petitioner alleges two errors regarding the Special Master’s application of the burden of
proof; he argues that the Decision applied a heightened burden of proof and that it failed to shift
the burden onto the Government. Because the appropriate burden of proof is a question of law,
the Court applies the “not in accordance with law” standard. 42 U.S.C. § 300aa-12(e)(2)(B);
Althen, 418 F.3d at 1277–78.

               1.      Heightened Burden

        Petitioner states that the Special Master erred in “finding that because Petitioner could
not eliminate the other ‘potential causative agent’ in the record for GBS, to wit: a previous GI
infection,” Petitioner failed to establish but-for causation under Althen prong two. Pet’r’s Br.
at 11 (quoting Dec. at 33). Petitioner alleges that in doing so, “the Special Master raised
Petitioner’s burden of proof and committed legal error in deciding this question.” Id.

        Respondent argues that because this is not a Table case, Petitioner enjoys no favorable
presumption and is instead required to show that the vaccine was “the ‘but for’ cause of his
harm, and the ‘reason for the injury.’” Resp. at 8 (quoting Pafford, 451 F.3d at 1356).
Respondent notes that the Special Master “specifically ‘acknowledge[d] that Petitioner is not
required to eliminate other potential causes in order to be entitled to compensation.’” Id. (citing
Dec. at 32). The Government argues that Petitioner’s objection, though couched in terms of
legal standards, merely amounts to a disagreement with how the Special Master weighed the
evidence, a matter that is entitled to substantial deference. Id. at 9.

         Respondent quotes the Federal Circuit for the proposition that a petitioner could satisfy
the first and third prongs of the Althen test, but still fail to satisfy the second prong “when
medical records and medical opinions do not suggest that the vaccine caused the injury, or where
the probability of coincidence or another cause prevents the claimant from proving that the
vaccine caused the injury by preponderant evidence.” Id. (emphasis omitted) (quoting
Capizzano v. Sec’y of Health & Hum. Servs., 440 F.3d 1317, 1326–27 (Fed. Cir. 2006)).

        The Special Master did not erroneously impose on Petitioner a heightened burden of
proof. The Vaccine Act requires that a petitioner prove by a preponderance of the evidence that
a vaccination caused her to “sustain[ ] . . . any illness, disability, injury, or condition.” 42 U.S.C.
§§ 300aa-11(c)(1)(C)(ii)(I); 300aa-13(a). The Secretary of Health and Human Services may
raise a “factors unrelated” defense. Id. § 300aa-13(a)(1)(B). This defense provides that if the
petitioner establishes a prima facie case, but the government proves by a preponderance of the
evidence that the injury is due to factors unrelated to the vaccine, the petitioner will not be
entitled to compensation. See id. Where the government submits evidence in support of an
alternative theory of causation, the special master may consider that evidence in determining

                                                  12
whether a petitioner has made a prima facie case. In other words, a special master’s
consideration of the government’s evidence does not necessarily impose on a petitioner an
improperly heightened burden to disprove the government’s alternative theory of causation.

        In Stone, the Federal Circuit considered the question of whether, in assessing an off-
Table petitioner’s case, “a special master may consider evidence of other possible causes for the
injury in question, or whether evidence of other possible causes may be considered only in
connection with the ‘factors unrelated’ defense on which the government has the burden of
proof.” 676 F.3d at 1379. The Court determined that its “decisions support the common-sense
proposition that evidence of other possible sources of injury can be relevant not only to the
‘factors unrelated’ defense, but also to whether a prima facie showing has been made that the
vaccine was a substantial factor in causing the injury in question.” Id. at 1379–80 (first citing
de Bazan v. Sec’y of Health & Hum. Servs., 539 F.3d 1347, 1353 (Fed. Cir. 2008), and then
citing Pafford, 451 F.3d at 1358–59).

        As the Stone court stated, “in some cases a sensible assessment of causation cannot be
made while ignoring the elephant in the room—the presence of compelling evidence of a
different cause for the injury in question.” Id. at 1380. See also de Bazan, 539 F.3d at 1353
(“The government, like any defendant, is permitted to offer evidence to demonstrate the
inadequacy of the petitioner’s evidence on a requisite element of the petitioner’s case[-]in-
chief.”); Doe v. Sec’y of Health & Hum. Servs., 601 F.3d 1349, 1356–58 (Fed. Cir. 2010) (citing
42 U.S.C. § 300aa-13(a)(1)) (stating that “[a]llowing the special master to consider evidence of
[an alternative theory of causation] did not improperly shift the burden to [the petitioner] to rule
out alternative causes”; evidence of an alternative theory of causation was “just one factor among
many that the special master relied on in concluding that ‘the facts of the case’ did not support
[the petitioner’s] theory of causation, and thus failed to establish a prima facie case”; and that
“[a] petitioner’s failure to meet his burden of proof as to the cause of an injury or condition is
different from a requirement that he affirmatively disprove an alternative cause”).

        Thus, evidence supporting alternative theories of causation is relevant to the assessment
of whether a petitioner has made a prima facie showing that the vaccination caused the injury. In
considering this evidence, the Special Master applied the correct burden and did not require that
Petitioner disprove other theories of causation. Indeed, the Special Master expressly
“acknowledge[d] that Petitioner is not required to eliminate other potential causes in order to be
entitled to compensation.” Dec. at 32 (citing Walther, 485 F.3d at 1149–52). The Special
Master also correctly “consider[ed] ‘evidence of other possible sources of injury’—here,
Petitioner’s GI illness—in determining ‘whether a prima facie showing has been made that the
vaccine was a substantial factor in causing the injury in question.’” Id. at 33 (quoting Stone, 676
F.3d at 1379).

       The Federal Circuit has recognized that “a petitioner as a practical matter may be
required to eliminate potential alternative causes where the petitioner’s other evidence on
causation is insufficient.” Walther, 485 F.3d at 1149–50. However, while “a petitioner need not
show the asserted vaccine was the predominant cause,” a petitioner still “must show that it was
substantial.” Id. at 1151 n.4. The Federal Circuit added that “[w]here multiple causes act in
concert to cause the injury, proof that the particular vaccine was a substantial cause may require

                                                13
the petitioner to establish that the other causes did not overwhelm the causative effect of the
vaccine.” Id.

        This aptly describes the present case. The Special Master noted that Petitioner’s expert
opined that it was impossible to determine whether the vaccination or diarrheal illness alone
caused his GBS, or whether they worked in concert. Dec. at 32. However, the expert “did not
explain how the vaccines and GI illness could work together in concert to cause GBS” and “did
not support this statement with medical literature or other evidence.” Id. The Special Master
gave little weight to Dr. Rinker’s argument that “the mere presence of diarrhea before the onset
of GBS . . . provides an unlikely cause of Mr. Winkler’s GBS in comparison to the Tdap
vaccination.” Dec. at 23 (quoting Pet. Ex. 31 at 2). She concluded that even if that is true, it
“does not explain how the Tdap vaccine is the more likely cause of Petitioner’s GBS.” Dec.
at 32. Because the Special Master found Petitioner’s evidence of causation to be insufficient,
particularly in light of the evidence supporting an alternative theory of causation, she determined
that Petitioner failed to make a prima facie case for causation. See Walther, 485 F.3d
at 1151 n.4.

               2.      Assignment of the Burden

        Petitioner further argues that the vaccination and GI illness may have worked in concert
and that the burden is not on Petitioner to establish that the vaccination was the predominant
cause. He states that “[t]he legal doctrines of legal causation do not require that a substantial
cause be a predominant cause,” and that “[w]here there are multiple independent potential
causes, where harm has been caused by only one of them but there is uncertainty as to which
one, the burden is upon Respondent to prove that it was their proposed cause and not the
vaccination which caused the harm.” Pet’r’s Br. at 20. He concludes that “Respondent has
failed to show that the unidentified gastrointestinal infection played any role in causing
Petitioner’s GBS.” Id.

        The Special Master did not erroneously fail to shift the burden onto Respondent. The
type of burden-shifting that Petitioner describes only applies “once the petitioner has established
a prima facie case.” Walther, 485 F.3d at 1151. “Once a petitioner establishes her prima facie
case by satisfying the Althen test, the burden then shifts to the respondent to show by a
preponderance of the evidence that the injury is due to factors unrelated to the administration of
the vaccine.” Deribeaux ex rel. Deribeaux v. Sec’y of Health & Hum. Servs., 717 F.3d 1363,
1367 (Fed. Cir. 2013) (citing 42 U.S.C. § 300aa–13(a)(1)(B)); see also de Bazan, 539 F.3d
at 1354 (holding that to “prov[e] by preponderant evidence that a particular agent or condition
(or multiple agents/conditions) unrelated to the vaccine was in fact the sole cause” is “the
government’s burden once the petitioner has met her burden” (second emphasis added)). The
Special Master concluded that Petitioner failed to establish a prima facie case that the
vaccination caused the injury, which ended the inquiry. Dec. at 32–33. There was no need to
shift the burden to Respondent.

                                                 14
       B.      Whether the Special Master Erred in Considering Evidence Concerning a GI
               Infection

        Petitioner argues that the Special Master’s consideration of evidence of a C. jejuni
infection was harmful error because the Special Master never found, and the record does not
support, that Mr. Winkler suffered from a C. jejuni infection. Pet’r’s Br. at 13–20. He couches
his objections in two ways. The first is to challenge the relevance of Respondent’s evidence and
the second challenges the Special Master’s assessment of that evidence.

               1.      Relevance

        The question of “what evidence is relevant to determining under the Vaccine Act that a
condition or injury is unrelated to administration of the . . . vaccine [is] a question of law,” which
is reviewed under the “contrary to law” standard. See, e.g., Deribeaux, 717 F.3d at 1366–67.
Petitioner claims that “[b]ecause AIDP and AMAN are separate diagnoses that affect different
parts of the nervous system, and are not equally caused by C. jejuni, the Special Master
committed reversible error by failing to address this important diagnostic issue of whether
Petitioner suffered from AIDP or AMAN.” Pet’r’s Br. at 17 n.7.

        Petitioner also states that, in discussing the prevalence of C. jejuni infections in the
general population and among GBS patients, Dr. Chaudhry introduced statistical evidence. See
Pet’r’s Br. at 18. Relying on Knudsen v. Secretary of Health and Human Services, 35 F.3d 543,
550 (1994) and Boatmon v. Secretary of Health and Human Services, 941 F.3d 1351, 1363
(2019), Petitioner insists that “[e]vidence discussing probability, generalizations, and statistical
likelihoods cannot be utilized in the instant case to show that Petitioner followed a general trend”
and that “such statistics are not germane” to the question of causation. Pet’r’s Br. at 18.
Additionally, Petitioner argues that the Special Master’s reliance on Dr. Whitton’s opinion
regarding the latency between diarrheal illness and the onset of GBS is “legally inapt absent a
concomitant finding that Petitioner likely suffered a C. jejuni illness.” Id. at 19.

        Respondent counters that, because the burden of proof is on Petitioner, the validity of
evidence concerning C. jejuni does not depend on a finding that Petitioner more likely than not
had a C. jejuni infection. Resp. at 13. Respondent notes that in Knudsen, the Federal Circuit
held that a viral infection can be an alternative cause, “even though the viral infection is not in
the particular case specifically identified by type or name.” Id. at 13–14 (quoting Knudsen, 35
F.3d at 549). Although Petitioner took issue with Dr. Chaudhry’s statements regarding C. jejuni,
Respondent notes that he addressed other types of infection in his report as well. Id. at 14–15.
The Government adds that regardless of any finding regarding C. jejuni, it is undisputed that Mr.
Winkler had a GI infection, diagnosed as gastroenteritis, and Dr. Whitton’s testimony on
incubation periods was not limited to that of C. jejuni. Id. at 15–16.

        On the matter of statistical evidence, Respondent distinguishes Knudsen. For that Table
case, “bare statistical fact” was insufficient to overcome the presumption that a vaccine had
caused an injury, but Respondent notes that the burden in the present case is on Petitioner.
Resp. at 11 (quoting Knudsen, 35 F.3d at 547). Respondent further argues that the evidence in
the present case is epidemiological, rather than merely statistical. See Resp. at 11–13. It quotes

                                                 15
Holmes v. Secretary of Health and Human Services for the proposition that “[s]tatistics, after all,
are in large part what epidemiology is all about, and causation can without question be based on
epidemiological evidence.” Id. at 12 (quoting Holmes, 115 Fed. Cl. 469, 485 (2014)).
Respondent further claims that the experts’ opinions regarding the latency of bacterial infections
were relevant, particularly because “the only evidence in this case linking the Tdap vaccine to
Petitioner’s GBS . . . is temporal proximity,” which is “insufficient as a matter of law.” Id. at 16
(citing Grant v. Sec’y of Health & Hum. Servs., 956 F.2d 1144, 1148 (Fed. Cir. 1992).

        The Special Master’s consideration of evidence concerning a GI infection was not
contrary to law. The relevance of this evidence is not predicated on the Special Master first
establishing “that Petitioner likely suffered a C. jejuni illness.” Pet’r’s Br. at 19. Rather, this
evidence is part of the inquiry into whether Petitioner made a prima facie case for causation. To
hold that such evidence is irrelevant unless the Special Master first finds that alternative
causation was likely would inappropriately force the Special Master to ignore “the elephant in
the room—the presence of compelling evidence of a different cause for the injury in question.”
Stone, 676 F.3d at 1380. Doing so would require the Special Master to find that Petitioner has
made a prima facie case when in fact he has not.

        Further, the Government may establish causation by a preponderance of the evidence
without identifying the precise alternative cause. See Knudsen, 35 F.3d at 549 (stating that
“there is nothing in the Vaccine Act that requires a per se rule that alternative causation cannot
be proved when the specific virus is not identified” and “hold[ing] that a ‘viral infection’ can be
an alternative causation, even though the viral infection is not in the particular case specifically
identified by type or name”). It follows that similar evidence would be relevant and reliable
when the party offering it does not carry the burden of proof.

        Similarly, the Special Master did not err by failing to address the “diagnostic issue” of
whether Mr. Winkler suffered from the AIDP or AMAN subtype of GBS. “[T]he function of a
special master is not to ‘diagnose’ vaccine-related injuries, but instead to determine ‘based on the
record evidence as a whole and the totality of the case, whether it has been shown by a
preponderance of the evidence that a vaccine caused [the petitioner’s] injury.’” Andreu, 569
F.3d at 1382 (quoting Knudsen, 35 F.3d at 549); see also Broekelschen v. Sec’y of Health &
Hum. Servs., 618 F.3d 1339, 1346 (Fed. Cir. 2010) (citing Kelley v. Sec’y of Health & Hum.
Servs., 68 Fed. Cl. 84, 100–01 (2005) for the proposition that “the petitioner [is] not required to
categorize his injury where the two possible diagnoses [are] ‘variants of the same disorder’”).

        Nor did the Special Master err in considering statistical and epidemiological evidence.
Bare probabilities are insufficient, but “causation can be found in vaccine cases based on
epidemiological evidence and the clinical picture.” Knudsen, 35 F.3d at 549. Petitioner’s
reliance on Boatmon is also unavailing. In that case, the Court held that relying on statistics “[i]n
the absence of actual evidence” cannot prove causation. 941 F.3d at 1362–63. But in this case,
Respondent’s epidemiological evidence supplements “actual evidence” of a GI infection, which
is the basis offered as an alternative cause.

                                                 16
       2.      Discretion

        The question of how to evaluate evidence is a discretionary matter for which special
masters are entitled to substantial deference. See Munn, 970 F.2d at 871 (stating that the Court
does not “reweigh the factual evidence, . . . assess whether the special master correctly evaluated
the evidence [,] . . . [or] examine the probative value of the evidence or the credibility of the
witnesses”). The Court reviews “discretionary rulings under the abuse of discretion standard.”
Id. at 870–73 & n.10. Special masters have wide latitude to decide what evidence to consider, as
well as how to weigh that evidence. See id. at 871.

        Petitioner claims that because the record does not indicate whether he was ever tested to
determine the cause of his GI illness, Dr. Chaudhry’s opinion discussing the possibility that the
GI illness was caused by C. jejuni is “inherently unreliable.” Pet’r’s Br. at 17. In his view, this
affects “how much weight to afford the offered opinion.” Id. at 16 (citing Broekelschen, 618
F.3d at 1347). Respondent counters that the Special Master’s consideration of evidence
regarding GI illnesses that cause GBS was appropriate and relevant. Resp. at 11–14. The
Government further states that the Special Master “properly considered” evidence of Mr.
Winkler’s GI illness and adds that weighing evidence is “a matter well within the Special
Master’s purview that is entitled to substantial deference on review.” Resp. at 9.

        The Special Master did not abuse her discretion in considering this evidence. “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.’ As such, the special
master’s credibility findings ‘are virtually unchallengeable on appeal.’” Lozano v. Sec’y of
Health & Hum. Servs., 958 F.3d 1363, 1370 (Fed. Cir. 2020) (citation omitted) (quoting
Broekelschen, 618 F.3d at 1347). If the special master “has considered the relevant evidence of
record, drawn plausible inferences and articulated a rational basis for the decision,” then
“reversible error is ‘extremely difficult to demonstrate.’” Lampe, 219 F.3d at 1360 (Fed. Cir.
2000) (quoting Hines, 940 F.2d at 1528).

        The Special Master’s analysis, including her assessment of the experts’ reliability, meets
these standards. She “weighed the conflicting evidence and concluded that Petitioner[] had not
carried [his] burden of demonstrating” a causal relationship between the Tdap vaccine and Mr.
Winkler’s GBS. See Porter v. Sec’y of Health & Hum. Servs., 663 F.3d 1242, 1254 (Fed. Cir.
2011). It is not the role of this Court to “reweigh the factual evidence or assess whether the
special master correctly evaluated the evidence,” or to “examine the probative value of the
evidence or the credibility of the witnesses,” because “[t]hese are all matters within the purview
of the fact finder.” Id. (first citing Broekelschen, 618 F.3d at 1349; and then citing Lombardi,
656 F.3d at 1354).

        In this case, the Special Master provided a “thorough and careful evaluation of all of the
evidence including records, tests, reports, and medical literature, as well as the experts’ opinions
and their credibility.” Id. Under the applicable standard of review, this is enough. Accordingly,
the Special Master’s determination that Petitioner failed to prove causation in fact by a
preponderance of the evidence was not arbitrary, capricious, an abuse of discretion, or otherwise
not in accordance with law.

                                                 17
IV.    Conclusion

       The Court is sympathetic to Mr. Winkler, who has suffered from GBS and placed private
medical information into the public record in pursuing this action. However, he has not
demonstrated that his illness was caused by the vaccination he received in 2017. Because the
Special Master’s Decision was not arbitrary, capricious, an abuse of discretion, or otherwise not
in accordance with law, Petitioner’s Motion for Review is DENIED and the Decision is
AFFIRMED. The Clerk is directed to enter judgment accordingly.

       IT IS SO ORDERED.

                                                  s/ Carolyn N. Lerner
                                                 CAROLYN N. LERNER
                                                 Judge

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