Court Opinion

ID: 4392702
Source: CourtListenerOpinion
Date Created: 2019-05-01 16:01:37.60772+00
Date Added: 2024-06-11T14:51:52.811320
License: Public Domain

In the United States Court of Federal Claims
                                     OFFICE OF SPECIAL MASTERS
                                              No. 16-994V
                                          (Not to be published)

*************************
NICHOLAS ZUMWALT,                   *
on behalf of his minor child, L.Z., *
                                    *                                     Special Master Corcoran
                       Petitioner,  *
                                    *                                     Filed: March 21, 2019
v.                                  *
                                    *                                     Tetanus-Diphtheria-Acellular
SECRETARY OF HEALTH AND             *                                     Pertussis Vaccine; Seizure Disorder;
HUMAN SERVICES,                     *                                     Althen Prong One; Treating Doctor
                                    *                                     Opinion; Althen Prong Two.
                       Respondent.  *
                                    *
*************************

Andrew D. Downing, Van Cott & Talamante, Phoenix, AZ, for Petitioner.

Ryan D. Pyles, U.S. Dep’t of Justice, Washington, DC, for Respondent.

                                        ENTITLEMENT DECISION1

       Nicholas Zumwalt, as legal representative of his minor child, L.Z., filed a petition on
August 12, 2016, seeking compensation under the National Vaccine Injury Compensation Program
(“Vaccine Program”).2 Pet. at 1 (ECF No. 1). Mr. Zumwalt alleged that L.Z.’s seizure disorder
was caused by some or all of the following vaccines administered on March 24, 2014: Prevnar 13
(pneumococcal), Pediarix (polio, hepatitis B, and diphtheria-tetanus-acellular pertussis (“DTaP”)),

1
  Although this Decision has been formally designated “not to be published,” it will nevertheless be posted on the
Court of Federal Claims’ website in accordance with the E-Government Act of 2002, 44 U.S.C. § 3501 (2012). This
means that the Decision will be available to anyone with access to the internet. As provided by 42 U.S.C. § 300aa-
12(d)(4)(B), however, the parties may object to the Decision’s inclusion of certain kinds of confidential information.
Specifically, under Vaccine Rule 18(b), each party has fourteen 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 current form. Id.
2
 The Vaccine Program comprises Part 2 of the National Childhood Vaccine Injury Act of 1986, 42 U.S.C. §§ 300aa-
10–37 (2012) (hereinafter “Vaccine Act” or “the Act”). Individual section references hereafter shall refer to § 300aa
of the Act.
ActHib 4 (Haemophilus influenzae type B) (“Hib”), and RotaTeq (rotavirus). Id.

        An entitlement hearing was held in this matter on October 9, 2018. After consideration of
the record and testimony provided at hearing, I find that Petitioner is not entitled to a compensation
award. As discussed in more detail below, Petitioner has not set forth a reliable theory explaining
how any of the vaccines L.Z. received on March 24, 2014, could have caused his injuries.

I.         Factual Background

           Pre-Vaccination History

        L.Z. was born premature at almost thirty-six weeks on September 24, 2013. Ex. 21 at 4,
filed Nov 3, 2016 (ECF Nos. 11-3–11-4). He spent his first six days in the neonatal intensive care
unit due to a high heart rate at birth, which was ultimately diagnosed as supraventricular
tachycardia.3 Id. His heart rate decreased after cardioversion,4 and he was prescribed medication
to help him maintain a normal heart rate thereafter. Id. at 5.

        At his one-month well-child visit with Geeta Silas, M.D., L.Z. seemed to be in good health.
See Ex. 3 at 72–75, filed Aug. 23, 2016 (ECF No. 5-3). The only concern noted was a rash near
his urethral opening, and Dr. Silas recommended he continue to receive heart rate medication
prophylactically. Id. at 74–75. L.Z.’s two-month check-up was similarly unremarkable. Id. at 67–
71. He received his two-month vaccinations without incident, and Dr. Silas deemed his
development to be appropriate for his age in all areas, although he continued to receive heart rate
medication. Id. at 67, 70–71.

        While L.Z.’s overall physical health at his four-month well-child check-up appeared good,
Dr. Silas began to express concerns about his development. See Ex. 3 at 61–66. Specifically, she
noted delays in his social interaction and eye contact, which she found to be “inconsistent for age.”
Id. at 61. He passed eight of the twelve developmental milestones assessed at this visit but failed
to visually track objects beyond the midline, bring a toy to his mouth while in a supine position,
orient to a voice, or laugh out loud. Id. at 62. She also noted that L.Z. would frequently spit up,
indicating reflux. Id. at 61. Dr. Silas prescribed Zantac (ranitidine) for L.Z.’s reflux and continued
digoxin for his heart. Id. at 65. He received his four-month vaccinations, again without incident.
Id. at 65.

       On March 24, 2014, L.Z. presented for his six-month check-up with Dr. Silas. Ex. 3 at 55–
59. At this visit, Dr. Silas expressed additional concerns about his development. See id. In

3
 Supraventricular tachycardia is an elevated heart rate, specifically occurring where contraction begins above the
heart’s ventricles. Dorland’s Illustrated Medical Dictionary 1867–68 (32nd ed. 2012) (hereinafter “Dorland’s”).
4
    Cardioversion is an electric shock given to restore the normal heart rate. Dorland’s at 295.

                                                             2
particular, she identified increased tone in his lower extremities, head lag, problems with eye
contact, and that he held his hands in tight fists.5 Id. at 57. She noted in the relevant medical record
“slight delay!!” and “inappropriate interaction” with regard to his neurological and psychiatric
systems, and he failed two of the twelve six-month developmental milestones: reaching for and
raking at objects, and transferring objects hand to hand (by five months of age). Id. at 56–57. Based
upon these developmental concerns, Dr. Silas referred L.Z.’s parents to Laura Taylor, D.O., a
pediatric development specialist, and to the Oklahoma “SoonerStart” Early Intervention center.6
Id. at 58–59.

         Vaccinations and Alleged Reaction

        L.Z. received his six-month vaccinations at the March 24, 2014 visit with Dr. Silas:
ActHib 4 and Prevnar 13 in his left shoulder, Pediarix in his right shoulder, and RotaTeq orally.
Ex. 3 at 58. He did not experience any sort of reaction immediately after receiving the vaccines.
Tr. at 7. On March 28, 2014—four days after vaccination, but prior to L.Z.’s alleged reaction—he
was evaluated to determine eligibility for the early intervention services recommended by Dr.
Silas. See generally Ex. 12. Evaluators determined that L.Z. was eligible for such services based
on “delays (significant) . . . in adaptive, fine motor, and cognitive skills.” Id. at 3. L.Z. did not pass
the vision screening exam, and he was referred for a follow-up hearing appointment. Id. at 1.

        Despite the above developmental concerns documented in the record, Petitioner has stated
that he and Mrs. Zumwalt did not find L.Z.’s developmental delays to be of great concern, as they
perceived L.Z.’s development overall to be largely normal. See Ex. 1 at 1, filed Aug. 23, 2016
(ECF No. 5-1) (“Pet. Aff.”). Thus, Petitioner alleged that prior to his alleged vaccine reaction, L.Z.
ate and slept well, rolled over, smiled, laughed, and sucked his fists. Id. at 1. To the extent that the
Zumwalts did observe developmental delays, L.Z.’s parents attributed them to his prematurity. Id.

        According to Petitioner’s observations, L.Z.’s health began to decline sharply late in the
evening of April 1, 2014, eight days after the relevant vaccinations. Pet. Aff. at 1; Tr. at 7–8. L.Z.
did not rouse himself from his evening nap as he usually would, and when Mr. Zumwalt went to
wake him, he appeared limp, pale, and unresponsive. Pet. Aff. at 1; Tr. at 8. Petitioner
unsuccessfully attempted to elicit a response to various stimuli, including pain, his bottle, and
being bathed. Tr. at 8–9. There is no record evidence for the period between the March 24th
vaccinations and the evening of April 1st establishing any other related symptoms, however, and
none are alleged.

5
  While the medical records from this March 24, 2014 visit do not specifically discuss the significance of L.Z. making
tight fists, both of Petitioner’s experts testified at hearing that this could be indicative of a neurological condition. Tr.
at 54, 110.
6
  Based on the records filed in this case, SoonerStart appears to be a multidisciplinary care center that evaluates
children for developmental delays and provides care and assistance to such children. See generally Ex. 12, filed Aug.
23, 2016 (ECF No. 6-3).

                                                             3
        Concerned by L.Z.’s demeanor and failure to respond to stimuli, the Zumwalts brought
L.Z. to the pediatric emergency room (“ER”) at St. Francis Hospital in Tulsa, Oklahoma, on the
night of April 1, 2014. Pet. Aff. at 2. Petitioner reported that ER treaters observed L.Z.
experiencing seizure-like activity, and accordingly ordered a computerized tomography (“CT”)
scan of his head. Id. L.Z. was given anti-seizure medication which seemed effective. Ex. 11 at 45,
filed Aug. 23, 2016 (ECF Nos. 6-1–6-2). The CT scan was conducted and revealed no acute
intracranial abnormalities. Ex. 22 at 2464, filed Nov. 18, 2016 (ECF Nos. 13-1–13-10). L.Z. had
no fever associated with this initial seizure onset. Id. at 2522.

        The next evening (April 2, 2014),7 L.Z. was admitted to St. Francis in status epilepticus,
with right lip smacking and right clonic arm movement. Ex. 22 at 2522. At the time of this
admission, treaters now noted a low-grade fever. Id. He was initially seen on the general pediatric
floor but was soon transferred to the pediatric intensive care unit. Id. A head CT scan on the day
of his admission was abnormal, showing asymmetry with possible structural defects in the left
frontoparietal region. Ex. 11 at 45–46. An overnight continuous study electroencephalogram
(“EEG”) the night of April 2nd was also abnormal, reflecting left hemispheric slowing with
periodic lateralizing epileptiform activity over the left, but without seizures. Id. A brain magnetic
resonance imaging (“MRI”) conducted on April 4th, however, showed no evidence of structural,
infectious, or hemorrhagic/ischemic injury and was “completely normal.” Id. at 47. An initial
lumbar puncture showed cerebrospinal fluid (“CSF”) pleocytosis8 of 256 white blood cells. Ex. 22
at 1339. A repeat lumbar puncture performed soon thereafter, however, showed markedly reduced
(and hence less concerning) pleocytosis, with the count now down to 14 white blood cells. Id.

        L.Z. was discharged on April 17, 2014. Ex. 22 at 1923. At this time, he was prescribed
phenobarbital to control his seizures, Prevacid to control reflux, acyclovir for possible viral
infections, and additional anti-seizure medication. Id. at 1926. However, L.Z. suffered another
seizure ten days later on April 27, 2014, for which he returned to the St. Francis ER. Id. at 1321.
His parents reported that L.Z. had showed marked improvement during his time at home (and there
is no record evidence to the contrary), but then had begun to act strangely the evening of April
26th (no eye contact, not interactive). Id. at 1339. In the ER, L.Z. was treated with a variety of
aggressive medications, including benzodiazepines, phenobarbital, and Keppra, but his seizing
continued, and he was subsequently placed in a pentobarbital-induced coma on April 29th. Id. at

7
  It is unclear from the record whether L.Z. was discharged from the St. Francis pediatric ER and returned to the
hospital less than one day later, or whether he was simply transferred internally to another department. Compare Pet.
Aff. at 2 (describing ER admission on evening of April 1 and stating that L.Z. was “admitted to the hospital for
additional tests” after CT scan and not discharged until April 17, 2014) with Ex. 22 at 2522 (April 2nd admit/transfer
note stating that L.Z. had a seizure twenty-four hours earlier, “was evaluated in another emergency department and
then sent home”).
8
 Pleocytosis is characterized by the presence of a higher number of white blood cells in the CSF than usual. Dorland’s
at 1460. Both parties’ experts agreed that pleocytosis is evidence of an existing inflammatory process. Tr. at 101, 162.

                                                           4
1321, 1341. A May 6th MRI showed decreased brain volume since his previous MRI on April 4th.
Ex. 22 at 1677. L.Z. was transferred to Cook Children’s Hospital in Fort Worth, Texas, on May
6th, where additional intense medication still failed to put a stop to his seizures. Ex. 13 at 426,
filed Aug. 23, 2016 (ECF Nos. 6-4–6-5).

        On May 14, 2014, L.Z. was transferred back to St. Francis. Pet. Aff. at 2. A twenty-four-
hour video EEG was conducted from May 25th–26th. Ex. 22 at 1163. The exam showed frequent
electrographic seizures, centralized background slowing with right hemispheric asymmetric
slowing, and frequent multifocal epileptiform discharges, but no clinical seizures. Id. at 1163–64.
L.Z.’s treating pediatric neurologist, David Siegler, M.D., (whose testimony at hearing is discussed
in detail below) deemed these results consistent with a diagnosis of infantile epileptic
encephalopathy. Id. at 1164. The records from this part of L.Z.’s medical history do not identify
the March 2014 vaccinations as potentially causal.

       L.Z.’s condition has not changed significantly since his discharge from St. Francis on May
25, 2014. Records from late July 2016 show that he is still profoundly disabled, nonverbal,
dependent on a feeding tube, and has poor visual interaction. Ex. 23 at 11, filed Dec. 7, 2016 (ECF
No. 14-1). According to his father, L.Z. requires constant care, suffers frequent seizures, is
quadriplegic, and has experienced severe brain volume loss. Pet. Aff. at 3.

         Elimination of Possible Etiologies

        In June of 2014, Dr. Siegler informed the Zumwalts that the etiology of L.Z.’s condition
might never be ascertained. Ex. 11 at 35. Nevertheless, over the months and years following L.Z.’s
two initial hospitalizations, many possible explanations were considered but eliminated. At Cook
Children’s, for example, treaters speculated that L.Z. might have Alpers’ disease9 or a genetic
disorder related to a POLG1 genetic mutation, but test results for both were ultimately negative.
Ex. 11 at 170; Ex. 22 at 89, 1180. An initial fifty-gene epilepsy panel screening was also negative,
meaning that it showed no known pathogenic genetic mutation. Ex. 13 at 134. And August 1, 2014
lab tests for autoimmune conditions that could have triggered encephalopathy revealed no causal
autoantibodies. Ex. 10 at 1–2, filed Aug. 23, 2016 (ECF No. 5-10).

        In January 2015, L.Z. was referred to neurologist Cynthia Keator, M.D., who opined that
febrile induced refractory status epilepticus (“FIRES”) was the most accurate characterization of
his epileptic state, though she noted that the actual etiology of this condition was as yet unknown.
Ex. 11 at 140. At a June 2015 visit, Dr. Keator again maintained that L.Z. likely had FIRES of
unknown origin, though she also posited that his condition might be Aicardi-Goutières

9
  Alpers’ disease is a rare disease found in young children that results from a nuclear gene mutation. Dorland’s at 528.
It presents with progressive mental deterioration, seizures, motor problems, liver failure, and premature death. Id.

                                                           5
syndrome.10 Ex. 13 at 156.

        Testing performed in July 2015 revealed no disease-causing mitochondrial mutation or
disorder. Ex. 13 at 127. In October 2015, further genetic testing was conducted in the form of
whole exome sequencing. Ex. 13 at 128. This revealed only that L.Z. carries a variant in his UPF3B
gene. Id. His mother also carries this variant, and while it is associated with X-linked intellectual
disability, Petitioner reached out on his own to Dr. Jozef Gecz, a geneticist at the University of
Adelaide in Australia, who opined (based on Petitioner’s questions) that this genetic variant was
not likely the cause of L.Z.’s condition.11 Id.; Ex. 48 at 4, filed Nov. 3, 2017 (ECF No. 31-2).

        A year later (and after this case had been initiated), Dr. Siegler filed a report with the
Vaccine Adverse Event Reporting System (“VAERS”) on September 10, 2016, attributing L.Z.’s
seizure onset to his March 24, 2014 vaccinations. Ex. 17 at 1–2, filed Sept. 20, 2016 (ECF No. 9-
1). In the report, Dr. Siegler described L.Z.’s post-vaccination adverse event as “intermittent
periods of tonic activity of upper and lower extremities with clonus noted in the left lower
extremity.” Id. at 2. He wrote that the adverse event resulted in both “prolongation of
hospitalization” and “permanent disability.” Id. at 3.

II.      Witness Testimony

         Nicholas Zumwalt

        Mr. Zumwalt provided testimony at the hearing consistent with the contents of his affidavit.
Tr. at 4–29. He holds a master’s degree in nursing, works as a professor of nursing at the University
of Tulsa, and is preparing to defend his Ph.D. in nursing, specializing in “parent knowledge and
understanding of suffering in nonverbal children with special needs in a neurological injury.” Tr.
at 5.12

        According to Mr. Zumwalt, L.Z. was born one month premature, but was developing
normally until he received the vaccinations at issue. Tr. at 5–6. Prior to vaccination, he had
achieved early developmental milestones such as rolling over and sucking his fists, and he was
able to eat, sleep, and interact well for his age. Id. Significantly, immediately before and after
receiving his six-month vaccinations, L.Z. had no fever or other apparent illness, and L.Z. had no

10
    Aicardi-Goutières syndrome is a neuroimmune disorder caused by genetic mutation. A. Takanohashi, et al.,
Elevation of Proinflammatory Cytokines in Patients wth Aicardi-Goutières Syndrome, 80 Neurology 997, 997 (2013),
filed as Ex. A Tab 2, Oct. 27, 2017 (ECF No. 29-2).
11
  Although Dr. Gecz’s statement was obtained by Petitioner without the process of a formal evaluation of the sort
that might characterize a treater opinion, neither party contends that the UPF3B genetic variant caused L.Z.’s seizures,
and his view remains unrebutted.
12
  Although he testified as a fact witness in his capacity as L.Z.’s parent, Mr. Zumwalt’s statements were exceptionally
detailed and precise, largely due to his own professional experience in the medical field.

                                                           6
other immediate or identifiable reaction to the vaccinations. Id. at 6–7.

        The evening of April 1, 2014, was “when things changed,” as Mr. Zumwalt described. Tr.
at 8. After L.Z. went down for his evening nap, he did not rouse himself as he usually would, and
was lethargic and unresponsive when Petitioner attempted to wake him. Id. He also did not respond
to direct stimuli. Id. at 8–9. The Zumwalts took him to the ER late that evening, concerned by his
general appearance and his abnormal skin and breathing. Id. at 9.

        Petitioner described the events of L.Z.’s first ER visit in a manner consistent with what is
reflected in records from that visit, including L.Z.’s unremarkable CT scan, the series of
medications administered throughout the day on April 2, 2014, before his seizures stopped that
evening, and his two weeks of hospitalization for monitoring and further treatment. See Tr. at 9–
13. Mr. Zumwalt had informed ER treaters that L.Z. had received several vaccinations one week
prior, and recalled that no treater commented on whether they believed his son’s condition to be
vaccine-related. Id. at 11–12. L.Z. was discharged on prophylactic phenobarbital and acyclovir on
April 17th, and by this time, Mr. Zumwalt recalled, his son’s condition had improved significantly:
“we had our smiling baby, happy baby, cuddly baby back.” Id. at 13. He remained in this improved
condition for nine days. Id.

        Mr. Zumwalt next described how L.Z. began seizing again on April 26, 2014. Tr. at 13. At
the ER, L.Z. was heavily medicated in an attempt to break his seizures. Id. at 14. Petitioner
described the details of this ER visit and subsequent hospitalization in a manner consistent with
the medical records, recalling that L.Z. was placed in a medically-induced coma for one week, that
treaters later erroneously suspected L.Z. had a rare and fatal mitochondrial disorder known as
Alpers’ disease, and that L.Z. was ultimately discharged without a known etiology for his
condition. Id. at 14–17. In the years since, no specific cause for L.Z.’s seizures has been identified,
despite extensive testing for infectious causes, autoimmune antibodies, and whole exome
sequencing. Id. at 17–18.

        Petitioner concluded his direct examination testimony by describing L.Z.’s current
condition. Tr. at 19–22. L.Z. is a quadriplegic, takes food and medication through a tube, cannot
speak, frequently suffers bouts of pneumonia, has kyphosis and scoliosis, and must receive oxygen
through a breathing tube at all times. Id.

        During a brief cross-examination, Mr. Zumwalt was questioned about L.Z.’s pre-
vaccination referral to SoonerStart based upon developmental concerns. Tr. at 24–26. Petitioner
did not recall the specific basis for that referral, but characterized any concerns treaters may have
had as minor, opining that such an evaluation was simply suggested “out of caution.” Id.

                                                  7
       Dr. David Siegler

        Dr. Siegler testified at hearing on Petitioner’s behalf and filed one sixteen-page report. Tr.
at 30–65; Ex. 24, filed May 5, 2017 (ECF No. 20-1) (“Siegler Rep.”). Dr. Siegler is a pediatric
neurologist with a practice based in Tulsa, Oklahoma, and he has served as L.Z.’s treating
neurologist since April 3, 2014. Tr. at 31, 33. He testified in this case primarily as a fact witness,
describing his own observations of L.Z.’s clinical course, but also offering an opinion about the
causal role of vaccines in L.Z.’s disorder.

        As reflected in his curriculum vitae (“CV”), Dr. Siegler received his B.S. at Stanford
University, followed by his M.D. from the University of Texas Southwestern Medical School in
Dallas. Ex. 62 at 5, filed Sept. 17, 2018 (ECF No. 52-1) (“Siegler CV”); Tr. at 31. He completed
an internship and residency in pediatrics, followed by a residency in child neurology, all at
Stanford. Siegler CV at 4. He is board-certified in pediatric neurology, and currently teaches at
both the University of Oklahoma and Oklahoma State University, while being on staff at two
hospitals in Tulsa. Tr. at 32; Siegler CV at 3. He also runs a solo practice, Child Neurology of
Tulsa. Siegler CV at 1. Much of Dr. Siegler’s practice involves working with patients with
epilepsy, and he spends a significant amount of time reviewing EEGs. Tr. at 32.

        Dr. Siegler provided both an overview of L.Z.’s clinical course and an opinion about the
cause of his injury. Based on his experience as L.Z.’s treating neurologist, he opined that L.Z.
developed encephalitis and afebrile status epilepticus as a result of a neurologic inflammatory
cascade triggered by the vaccinations he had received eight days prior, and that this status
epilepticus brought about his ultimate catastrophic brain injury. Tr. at 43–44; Siegler Rep. at 15–
16. He based this both on his review of L.Z.’s test results and on the short time period between
vaccination and onset. Tr. at 41; Siegler Rep. at 15. While he did not discuss a mechanism of
causation in detail, he posited in his report that one of the vaccines L.Z. received on March 24,
2014, “could have induced an inflammatory cascade that culminated in his irreversible neurologic
injuries.” Siegler Rep. at 15.

        Dr. Siegler dedicated most of his written report to a detailed overview of L.Z.’s history that
was largely consistent with the medical record. See Siegler Rep. at 1–14. At hearing, Dr. Siegler
began his testimony with a review of L.Z.’s first EEG on April 3, 2014, which showed left side
epileptic activity. Tr. at 33–36. Dr. Siegler opined that L.Z.’s April 4th MRI reading, which was
normal, coupled with his elevated white blood count, suggested the existence of an inflammatory
event occurring at that time in L.Z.’s central nervous system. Id. at 36. Dr. Siegler also discussed
the stark contrast between L.Z.’s April MRI and his May MRI, interpreting the decreased brain
mass revealed in the May reading as evidence of ongoing diffuse brain atrophy. Id. at 39.

       Dr. Siegler deemed the FIRES diagnosis mentioned by Dr. Keator to be inapplicable and

                                                  8
unhelpful to L.Z.’s case. Tr. at 40–41. By its own terms, FIRES necessarily requires that the patient
have experienced a febrile illness, which L.Z. did not. Id. Furthermore, the term merely describes
a set of symptoms, rather than propose a possible etiology of a patient’s condition. Id.

        During cross-examination, Dr. Siegler agreed that L.Z. had some developmental issues
prior to vaccination (including visual tracking issues, head lag, and increased tone). Tr. at 52–54.
While he acknowledged that some of these symptoms could indicate a preexisting neurological
condition, he maintained that L.Z.’s pre-vaccination condition was so markedly different from
afterward that he could not associate the former concerns with the latter, more alarming
constellation of symptoms. Id. Dr. Siegler also acknowledged that, even though testing L.Z.
received in September 2015 had not identified a possible genetic explanation for his seizure
disorder, the list of identifiable genetic mutations associated with epilepsy has expanded in the
past several years, and that he thus has no way of definitively knowing whether L.Z. may have a
genetic mutation that contributed to his condition. Id. at 51.

         When pressed about his basis for believing that vaccines caused the onset of L.Z.’s
seizures, Dr. Siegler emphasized that he primarily based his opinion on the close temporal nexus
between vaccination and seizure onset, along with the lack of an identified alternative cause. Tr.
at 56.13

        Dr. Lawrence Steinman

        Lawrence Steinman, M.D., also testified and filed two reports on Petitioner’s behalf. Tr. at
66–134; Ex. 26, filed July 18, 2017 (ECF No. 24-1) (“Steinman Rep.”); Ex. 64, filed Nov. 12,
2018 (ECF No. 55-1) (“Steinman Supp. Rep.”).14 As shown in his CV, Dr. Steinman received his
B.A. from Dartmouth College and his M.D. from Harvard Medical School, and he completed
residencies in neurology and pediatrics at Stanford University. Ex. 27 at 1, filed July 18, 2017
(ECF No. 24-2) (“Steinman CV”). He has worked as a professor of neurology and pediatrics at
Stanford for the past thirty-eight years, and during that time he has also worked as an attending
physician at Stanford Children’s Hospital. Id.; Tr. at 68–69. He has published over five hundred
peer-reviewed publications on neurology and autoimmune disease. Steinman CV at 5–45; Tr. at
70. He has special expertise in the pertussis toxin, as thirteen of his numerous published articles
specifically pertain to the interaction of pertussis and the immune system (although he has not

13
  Respondent also raised issues of Dr. Siegler’s credibility during cross-examination. Specifically, Respondent’s
counsel questioned Dr. Siegler about his relationship with Petitioner’s counsel and the timing of his VAERS report.
Tr. at 47–49. Dr. Siegler acknowledged that he had previously been acquainted with Petitioner’s counsel and had
specifically recommended Mr. Downing to Petitioner. Id. at 47–48. He also acknowledged that he did not submit the
VAERS report until September of 2016—well over two years after the onset of L.Z.’s brain injury—at which point
he was aware that Petitioner was already pursuing litigation, although he explained that during the interim period he
had been attempting to rule out other possible explanations. Id. at 48–49.
14
  The second of Dr. Steinman’s two reports was filed one month after hearing, without Petitioner’s counsel first
seeking Respondent’s consent or leave of the Court prior to filing.

                                                         9
written on the topic in many years), and he patented certain work related to the development of the
acellular pertussis vaccine. Tr. at 74.

        Dr. Steinman dedicated the majority of his testimony to attempting to explain how one or
more of the vaccines L.Z. received on March 24, 2014, could have triggered the onset of his seizure
disorder. He focused upon two in particular: RotaTeq and DTaP. Dr. Steinman noted that the
RotaTeq package insert included a table showing a higher seizure incidence in patients who
received the vaccine over those who received a placebo. Tr. at 81–82 (discussing Ex. 33 at 3, filed
Aug. 2, 2017 (ECF No. 25-7)). Although he conceded that the difference between the reported
seizure incidence rates was not statistically significant, Dr. Steinman nonetheless maintained that
it was meaningful. Id. at 82–83. He did not attempt to explain a mechanism of causation for how
RotaTeq could trigger a seizure, however.15

        Next, Dr. Steinman turned to the DTaP vaccine, which he proposed could cause seizures
in two different ways. First, he suggested that the vaccine’s alum adjuvant (included in the vaccine
to increase its immunogenicity) drives a cytokine response that could become pathogenic. Tr. at
84, 98–99. In his written report, Dr. Steinman stated that “alum acts in the inflammosome, a
biochemical compartment within the cell associated with a broad spectrum of diseases including
seizure disorders in infants.” Steinman Rep. at 7. Certain cytokines are understood to induce
fevers, which in turn can trigger seizures—though he acknowledged that this had little relevance
to L.Z.’s case, as L.Z. did not experience a fever at the time of his initial hospitalization and first
seizures (nor did he run a fever at the time of vaccination). Id. at 98–99. Dr. Steinman did not
otherwise clearly explain the sequence of events, running from reaction to adjuvant to cytokine
upregulation, that would ultimately result in the triggering of L.Z.’s seizures.

        Dr. Steinman devoted far more time at hearing to discussing a second possible mechanism
of causation involving the DTaP vaccine. In summary, he theorized that the pertussis toxin in the
vaccine causes a specific kind of enzymatic activity, which in turn “kindle[s]” seizures. Steinman
Rep. at 6; Tr. at 84–99. L.Z. received the TDaP vaccine, which contains acellular pertussis. Tr.
at 88. The acellular pertussis component of the DTaP vaccine is intended to protect recipients
against pertussis, an acute and contagious infection of the respiratory tract also known as whooping
cough. Dorland’s at 1421. Although formulated to contain lower amounts of pertussis toxin than
its predecessor version,16 the acellular pertussis vaccine, Dr. Steinman noted, still contains some
pertussis toxin. In addition, the pertussis toxin (produced by the Bordatella pertussis bacterium) is
not only a factor in causing pertussis itself, but has also been implicated, in the context of
15
   Dr. Steinman also noted in his written report (although he did not raise the contention at hearing) that the Hib
vaccine’s package insert reflected a possible association with post-vaccination seizures like RotaTeq. Steinman Rep.
at 5–6.
16
  The newer “DTaP” vaccine that is more commonly administered today contains acellular pertussis, while the older
“DTP” vaccine was formulated with whole cell pertussis.

                                                        10
vaccination, in pediatric neurological conditions (albeit primarily in connection to the whole cell
form of the vaccine). S. Gomez, et al., ADP-Ribosylation Activity in Pertussis Vaccines and its
Relationship to the in vivo Histamine-Sensitisation Test, 25 Vaccine 3311 (2007), filed as Ex. 61,
Sept. 6, 2018 (ECF No. 51-10) (“Gomez”)). The pertussis toxin is also specifically understood to
play a role in ADP-ribosylation—an enzymatic protein modification process (occurring “post-
translational,” or after protein synthesis) important to cell signaling. Steinman Rep. at 7; K.
Edwards, et al., Pertussis Vaccines, in “Plotkin’s Vaccines” 713 (S. Plotkin, et al., eds., 7th ed.
2018); Tr. at 87–89 (citing Gomez).17

        Gomez considered the efficacy of the most common test for measuring the degree of
inactivation of detoxified pertussis toxin contained in the acellular form of DTaP: the histamine
sensitization test (“HIST”), an in vivo testing process involving mice. Gomez at 3312. That test is
a “lethal challenge” test,18 in which the pertussis toxin the mice receive from vaccination sensitizes
them to a subsequent anaphylactic shock instigated by histamine challenge. Id. at 3317. Because
HIST is subject to variability and has been deemed unethical, a substitute test has been sought in
the scientific/medical community. Id. at 3311–12.

        To identify a possible substitute safety test, Gomez compared HIST results with a
measurement of ADP-ribosylation enzyme activity in the same kinds of vaccines, reasoning that
because this enzyme activity has been hypothesized as “directly responsible for the toxicity”
measured by HIST, measuring it could be an alternative means of assessing vaccine safety. Gomez
at 3311–12. Gomez’s authors concluded that measuring ADP-ribosylation activity corresponded
well to HIST results for DTaP containing genetically-detoxified pertussis toxin, but did not find a
correlation between ADP-ribosylation activity results and HIST results for DTaP containing
chemically-detoxified pertussis toxin (which is more commonly used in vaccines). Id. at 3317.
The authors ultimately concluded that further evaluation was necessary to determine whether
measuring ADP-ribosylation activity accurately reflects the pertussis toxicity level in DTaP. In Dr.
Steinman’s view, Gomez supported his contention that ADP-ribosylation occurs in the presence
of the pertussis toxin, thus confirming that “the pertussis toxin activity is still [occurring] in the
acellular vaccines.” Tr. at 95–97 (discussing Gomez).

        Dr. Steinman further maintained that the ADP-ribosylation enzymatic process is also
integral to the triggering of seizures. In support of this, he cited two articles. The first posited that
when seizures are occurring (albeit due to some other cause), the resulting neuronal cell death may

17
  Dr. Steinman also cited to four other articles published between 1988 and 1992 as confirming the relationship
between pertussis toxin and neurologic injury, but at hearing conceded that no studies in the past twenty-seven years
have confirmed the assertions of these earlier works. See Steinman Rep. at 6, 9; Tr. at 118–19.
18
   A lethal challenge test involves injection of animals with a particular vaccine, followed by inoculation some time
later with a particular toxin that often results in the death of some of the animals. See Gomez at 3312; World Health
Organization Department of Immunization, Vaccines and Biologicals, Manual for Quality Control of Diphtheria,
Tetanus and Pertussis Vaccines, 26–27 (2013), https://www.who.int/biologicals/vaccines/pertussis/en.

                                                         11
be attributable in part to the presence of an enzymatic reaction involving poly(ADP-ribose)
polymerase (or “PARP”). Steinman Rep. at 6 (citing L. Chi, et al., Poly(ADP-Ribose) Signal in
Seizures-Induced Neuron Death, 71 Med. Hypotheses 283, 284–85 (2008), filed as Ex. 41, Sept.
6, 2018 (ECF No. 51-5) (“Chi”)). The second suggested that inhibiting PARP decreased seizure
activity. Tr. at 93 (citing S. Wang, et al., Poly(ADP-Ribose) Polymerase Inhibitor Is
Neuroprotective in Epileptic Rat Via Apoptosis-Inducing Factor and Akt Signaling, 18 Molecular
Neuroscience 1285 (2007), filed as Ex. 43, Sept. 6, 2018 (ECF No. 51-7) (“Wang”)).

        Wang describes an animal study in which seizures were induced with kainic acid19 in order
to evaluate the impact of seizure activity on activation of PARP in conjunction with a different
substance (3-Aminobenzamide (“3-AB”), a benzoic acid derivative) known to have
neuroprotective properties. Wang at 1285–86. Wang does not expressly equate the enzymatic
process involving PARP with ADP-ribosylation, but Dr. Steinman seems to have concluded that
the two are congruent. Tr. at 94 (characterizing PARP as “another member of this family of
enzymes” that included ADP-ribosylase). Wang’s authors concluded that 3-AB potentially could
assist in the treatment of “hippocampal neuron demise caused by seizures,” although the article
did not discuss pertussis toxin or explain how it might produce seizures with associated neuronal
damage. Wang at 1289. Dr. Steinman nevertheless maintained that Wang supported his contention
that “excessive ADP ribosylation” stimulated by pertussis toxin could be neurologically harmful
(because Wang established that suppression of PARP reduced neuronal harm). Steinman Rep. at
6; Tr. at 94–95.

        Dr. Steinman also attempted to explain why the approximately eight-day timeframe
between vaccine receipt and seizure onset was medically appropriate, citing Gomez in support. Tr.
at 96–98. Gomez, he maintained, demonstrated that HIST testing conducted five days after
vaccination of mice with pertussis toxin-containing vaccines revealed evidence of ADP-ribosylase
activity within a day or more later—allowing him to opine that the seizure-inducing properties of
that process could take seven or eight days total. Id. at 97–98; Gomez at 3313. In his one-page
supplemental report, Dr. Steinman further asserted that the pertussis toxin could have a biologic
effect in the body beyond five days. Steinman Supp. Rep. at 1 (citing J. Munoz, et al., Biological
Activities of Crystalline Pertussigen from Bordatella Pertussis, 33 Infection & Immunity 820
(1981), filed as Ex. 65, filed Nov. 12, 2018 (ECF No. 56-1) (“Munoz”)). Dr. Steinman otherwise
confirmed, however, that he could cite no published medical literature in the past thirty years that
had expressly hypothesized that ADP-ribsolyation causes seizure disorders in the context of
vaccines, or that it does so in the timeframe proposed. Tr. at 118–19.

       Dr. Steinman provided no additional evidence to explain how any of the vaccines L.Z.
received, individually or in concert, could have caused a seizure disorder that would present

19
 Kainic acid is a potent, naturally-occurring neurotoxin found in some types of seaweed. C. Hammond, Cellular and
Molecular Neurophysiology § 10.3 (4th ed. 2015).

                                                       12
without fever, and with no other pre-seizure indications of an ongoing immunological reaction.
When questioned about how he could persuasively assert that L.Z.’s seizure disorder was caused
by vaccination, Dr. Steinman placed great importance on the fact that no other potential cause had
ever been identified. Tr. at 100. He did, however, emphasize his view that the pleocytosis noted
from L.Z.’s CSF testing was “smoking gun” proof, because it established the existence of some
inflammatory response at the time L.Z. first presented to the hospital. Id. at 101. He also admitted
(when questioned on cross examination) that some of L.Z.’s pre-vaccination symptoms could be
indicative of a neurologic condition, but added that such symptoms could “mean a lot of things”
not necessarily connected to the post-vaccination seizure activity. Id. at 109–10.

       Dr. John Zempel

         John Zempel, M.D., Ph.D., was the only witness to appear on Respondent’s behalf. He
testified at hearing and submitted two written reports, maintaining that L.Z.’s vaccinations did not
cause his seizure disorder. Tr. at 135–213; Ex. A, filed Oct. 24, 2017 (ECF No. 28-1) (“Zempel
Rep.”); Ex. C, filed Dec. 12, 2018 (ECF No. 64-1) (“Zempel Supp. Rep.”).

        As shown in his CV, Dr. Zempel received his B.S. from the University of Wisconsin-
Madison, followed by his M.D. and Ph.D. (in neurobiology) from Washington University in St.
Louis. Ex. B at 1, filed Oct. 24, 2017 (ECF No. 28-2) (“Zempel CV”). He completed residencies
in pediatrics and child neurology, followed by fellowships in pediatric epilepsy and clinical
neurophysiology. Id. at 2. He now teaches as a professor of neurology and pediatrics at Washington
University School of Medicine, while also working half the year on inpatient services at multiple
hospitals. Id. at 3; Tr. at 137. He estimated that his patient population is approximately 80%
children with highly refractory epilepsy. Tr. at 138. Dr. Zempel is board-certified in neurology
with a special qualification in child neurology, and he has published dozens of articles in medical
and scientific journals, largely focusing on epilepsy and other EEG issues. Id. at 137; Zempel CV
at 3, 5–8. He conceded, however, that his medical research does not directly involve vaccines or
immunology. Tr. at 170–71.

         In his hearing testimony and written report, Dr. Zempel made two overarching contentions:
first, that L.Z. likely had some neurologic abnormality before his March 24, 2014 vaccinations;
and second, that Dr. Steinman’s theory of vaccine causation was unsupported by the medical
literature upon which it relies. Tr. at 139–46, 148–52; 158–67; Zempel Rep. at 9–11.

         Dr. Zempel began with a discussion of L.Z.’s development before vaccination, finding
evidence of possible neurologic abnormalities even in his first months of life. Tr. at 139–46. He
noted “subtle but persistent concern” from treaters about possible developmental delay,
particularly with regard to his head lag, increased tone, poor visual interaction, and other motor
skills. Id. at 139–41. L.Z.’s head growth had slowed between his two-month and six-month check-
ups, which Dr. Zempel characterized as a concerning indication that L.Z.’s brain was failing to

                                                13
develop at an appropriate pace. Id. at 142–44. Based on these documented concerns, Dr. Zempel
concluded that there was “clear evidence” of neurologic abnormalities before L.Z. received his
six-month vaccinations. Id. at 144–46. He conceded, however, that such evidence would not
necessarily indicate a high epilepsy risk (and therefore was not necessarily predictive of the
outcome L.Z. has experienced). Id. at 146–47.

        Dr. Zempel next spoke about his assessment of L.Z.’s clinical course after vaccination and
ultimate diagnosis. He agreed that L.Z. did not have FIRES (given the lack of fever), but stated
that he may have experienced “new onset refractory status epilepticus” (or “NORSE”). Tr. at 154–
55. He clarified that NORSE, like FIRES, is simply a descriptive term, and does not explain the
condition’s etiology. Id. at 157–58. He ultimately opined that the underlying cause of L.Z.’s
epilepsy is as yet unknown, though he speculated that a yet-unidentified genetic component,
infectious agent, or mitochondrial disease may have played a causal role. Id. at 148–52.

         Dr. Zempel disagreed with Petitioner’s experts’ conclusion that vaccines may have played
a role in triggering L.Z.’s seizure onset. Tr. at 158–60. He found Dr. Steinman’s theory of causation
too incoherent to analyze or respond to in full, criticizing Dr. Steinman’s method of stringing
together discrete scientific or medical concepts into a “causal stream.” Id. at 168–69. In his report,
Dr. Zempel noted a gap in Dr. Steinman’s logic, stating that the medical literature cited by Dr.
Steinman “does not demonstrate that detoxified pertussis vaccine actually plays a role in seizures
and neuronal death, a key step in claiming causation.” Zempel Rep. at 10. In so maintaining, Dr.
Zempel disputed several of Dr. Steinman’s interpretations of medical literature or other evidence.
For example, he noted that while ADP-ribosylation could theoretically play a role in seizure
activity, key literature cited by Dr. Steinman for this point (like Wang) said nothing at all about
the seizure-inducing capacity of pertussis toxin. Tr. at 167.

        Dr. Zempel also took issue with the contention that L.Z.’s medical records established the
existence of an inflammatory event at the time of his hospitalization. Dr. Siegler read the change
between L.Z.’s April and May MRIs as evidence that “the brain abnormalities are not secondary
to status epilepticus but, rather, indicate[] a primary neuro-inflammatory destructive process.”
Siegler Rep. at 14. Dr. Zempel, by contrast, observed that the focal and global brain atrophy visible
in the second MRI was common to refractory status epilepticus, and therefore did not actually
corroborate the contention that L.Z. experienced a primary neuro-inflammatory destructive
process. Zempel Rep. at 9. Rather, the decrease in brain mass between L.Z.’s April and May 2014
MRIs could be attributed to the seizures he experienced in the intervening weeks. Id.; Tr. at 163.

       Ultimately, Dr. Zempel characterized L.Z.’s condition as idiopathic in origin. Tr. at 207.
Most of the catastrophic status epilepticus cases he is familiar with never obtain an etiological
explanation. Zempel Rep. at 10–11. Dr. Zempel clarified that he did not rely heavily on his
observations about L.Z.’s possible pre-vaccination neurologic abnormality in reaching this

                                                 14
conclusion. Tr. at 211–12. At most, these early signs of abnormality were simply indicia that
something else was going on. Id. He also admitted that L.Z.’s referral for developmental early
intervention services may only have been prophylactic and/or due to his premature birth, but
maintained that L.Z.’s demonstrated hypertonia and fisted hands were nonetheless indicia of pre-
vaccination neurologic abnormality. Id. at 175–76.

        In a two-page supplemental report filed in response to Dr. Steinman’s post-hearing
supplemental report, Dr. Zempel again criticized Dr. Steinman’s reliance on medical literature not
specific to the DTaP vaccine or pertussis toxin contained therein. Zempel Supp. Rep. at 1–2. Dr.
Zempel also pointed out that Munoz (published in the early 1980s) spoke only to the effects of the
active pertussis infection, not the impact of detoxified pertussis contained in the acellular DTaP
vaccine. Id. at 2. Thus, “[m]erely showing that the actual pertussis toxin [. . .] has prolonged
biological effects does not establish that the inactivated pertussis vaccine has any causal
relationship to a seizure that occurred eight days after vaccination, well outside the temporal
window demonstrated in epidemiological studies to be associated with seizures.” Id. at 1–2
(emphasis added).

III.   Procedural History

        As previously noted, this matter commenced with the filing of the Petition and Petitioner’s
supporting affidavit on August 12, 2016. Over the following months, Petitioner filed medical
records in support of his claim. Respondent thereafter filed a Rule 4(c) Report on February 15,
2017, asserting that compensation is not appropriate in this case. Petitioner subsequently filed a
report from Dr. Siegler on May 5, 2017, followed by an expert report from Dr. Steinman on July
18, 2017. Respondent filed a responsive expert report on October 24, 2017. The parties filed their
respective prehearing submissions over the summer of 2018, and a one-day hearing took place on
October 9, 2018.

         The parties elected not to file post-hearing briefs. Tr. at 215. However, on November 12,
2018, Petitioner filed an additional report from Dr. Steinman without first seeking leave of the
Court or Respondent’s consent. In the interest of fairness to the parties, I permitted Petitioner to
file this report and gave Respondent the opportunity to submit a supplemental filing of his own.
Respondent accordingly filed Dr. Zempel’s supplemental report on December 12th. This case is
now ripe for decision.

IV.    Applicable Legal Standards

       A.      Claimant’s 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

                                                15
to one of the vaccinations in question and also occurring 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; see also
Shalala v. Whitecotton, 514 U.S. 268, 270 (1995) (quoting Section 11(c)(1)(C)(i)); Moberly v.
Sec’y of Health & Human Servs., 592 F.3d 1315, 1321 (Fed. Cir. 2010); Capizzano v. Sec’y of
Health & Human Servs., 440 F.3d 1317, 1320 (Fed. Cir. 2006).20 Petitioner in this case asserts
only a non-Table claim.

        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).
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).

        For a non-Table claim, proof of medical certainty is not required. Bunting v. Sec’y of Health
& Human Servs., 931 F.2d 867, 873 (Fed. Cir. 1991). In such circumstances, 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 v. Sec’y of Health
& Human Servs., 165 F.3d 1344, 1352–53 (Fed. Cir. 1999)); Pafford v. Sec’y of Health & Human
Servs., 451 F.3d 1352, 1355 (Fed. Cir. 2006). A petitioner asserting a non-Table claim must satisfy
all three of the elements established by the Federal Circuit in Althen v. Secretary of Health &
Human Services: “(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.” 418 F.3d
1274, 1278 (Fed. Cir. 2005).

        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, the
petitioner’s theory must be based on a “sound and reliable medical or scientific explanation.”
Knudsen v. Sec’y of Health & Human 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.

20
  Decisions of special masters (some of which I reference in this ruling) constitute persuasive but not binding
authority. Hanlon v. Sec’y of Health & Human 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 & Human Servs., 59 Fed. Cl. 121,
124 (2003), aff’d, 104 F. App’x 712 (Fed. Cir. 2004); see also Spooner v. Sec’y of Health & Human Servs., No. 13-
159V, 2014 WL 504728, at *7 n.12 (Fed. Cl. Spec. Mstr. Jan. 16, 2014).

                                                         16
        Petitioners may satisfy the first Althen prong without resort to medical literature,
epidemiological studies, demonstration of a specific mechanism, or a generally accepted medical
theory. Andreu v. Sec’y of Health & Human Servs., 569 F.3d 1367, 1378–79 (Fed. Cir. 2009)
(citing Capizzano, 440 F.3d at 1325–26). Special masters, despite their expertise, are not
empowered by statute to conclusively resolve what are 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 v.
Sec’y of Health & Human Servs., 121 Fed. Cl. 230, 245 (2015), vacated on other grounds, 844
F.3d 1363 (Fed. Cir. 2017).

        In discussing the evidentiary standard applicable to the first Althen prong, many decisions
of the Court of Federal Claims and Federal Circuit have emphasized that petitioners need only
establish a causation theory’s biologic plausibility (and thus need not do so with preponderant
proof). Tarsell v. United States, 133 Fed. Cl. 782, 792–93 (2017) (special master committed legal
error by requiring petitioner to establish first Althen prong by preponderance; that standard applied
only to second prong and petitioner’s overall burden); Contreras, 121 Fed. Cl. at 245
(“[p]lausibility . . . in many cases may be enough to satisfy Althen prong one” (emphasis in
original)); see also Andreu, 569 F.3d at 1375. At the same time, there is contrary authority from
the Federal Circuit suggesting that the preponderance standard applied when evaluating a
claimant’s overall success in a Vaccine Act claim also bears on the first Althen prong. See, e.g.,
Broekelschen v. Sec’y of Health & Human Servs., 618 F.3d 1339, 1350 (Fed. Cir. 2010) (affirming
special master’s determination that expert “had not provided a ‘reliable medical or scientific
explanation’ sufficient to prove by a preponderance of the evidence a medical theory linking the
[relevant vaccine to relevant injury]”) (emphasis added). Regardless, one thing remains: petitioners
always have the burden of establishing their Vaccine Act claim overall with preponderant
evidence. W.C. v. Sec’y of Health & Human Servs., 704 F.3d 1352, 1356 (Fed. Cir. 2013) (citations
omitted); Tarsell, 133 Fed. Cl. at 793 (noting that Moberly “addresses the petitioner’s overall
burden of proving causation-in-fact under the Vaccine Act” by a preponderance).

        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 & Human 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’”)

                                                 17
(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 & Human Servs., 993 F.2d 1525, 1528 (Fed. Cir. 1993).

        However, medical records and/or statements of a treating physician’s views 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 & Human 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 suppositions or bases. The views of treating physicians should also be
weighed against other, contrary evidence also present in the record—including conflicting
opinions among such individuals. Hibbard v. Sec’y of Health & Human 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); Caves v. Sec’y of Health &
Human Servs., 100 Fed. Cl. 119, 136 (2011), aff’d, 463 F. App’x 932 (Fed. Cir. 2012); Veryzer v.
Sec’y of Health & Human Servs., No. 06-522V, 2011 WL 1935813, at *17 (Fed. Cl. Spec. Mstr.
Apr. 29, 2011), mot. for review denied, 100 Fed. Cl. 344, 356 (2011), aff’d without opinion, 475
F. App’x 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.” Bazan v.
Sec’y of Health & Human Servs., 539 F.3d 1347, 1352 (Fed. Cir. 2008). The explanation for what
is a medically acceptable timeframe must also coincide 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 &
Human Servs., 101 Fed. Cl. 532, 542 (2011), recons. denied after remand, 105 Fed. Cl. 353 (2012),
aff’d mem., 2013 WL 1896173 (Fed. Cir. 2013); Koehn v. Sec’y of Health & Human Servs., No.
11-355V, 2013 WL 3214877 (Fed. Cl. Spec. Mstr. May 30, 2013), mot. for review denied (Fed.
Cl. Dec. 3, 2013), aff’d, 773 F.3d 1239 (Fed. Cir. 2014).

       B.      Law 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

                                                 18
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 & Human Servs., 3 F.3d 415, 417 (Fed. Cir. 1993) (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 a determination is evidenced
by a rational determination).

        Medical records that are created contemporaneously with the events they describe are
presumed to be accurate and “complete” (i.e., presenting all relevant information on a patient’s
health problems). Cucuras, 993 F.2d at 1528; Doe/70 v. Sec’y of Health & Human Servs., 95 Fed.
Cl. 598, 608 (2010) (“[g]iven the inconsistencies between petitioner’s testimony and his
contemporaneous medical records, the special master’s decision to rely on petitioner’s medical
records was rational and consistent with applicable law”); Rickett v. Sec’y of Health & Human
Servs., 468 F. App’x 952 (Fed. Cir. 2011) (non-precedential opinion). This presumption is based
on the linked propositions that (i) sick people visit medical professionals; (ii) sick people 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 & Human Servs., No. 11-685V, 2013 WL 1880825, at *2 (Fed. Cl. Spec. Mstr. Apr. 10,
2013); Cucuras v. Sec’y of Health & Human Servs., 26 Cl. Ct. 537, 543 (1992), aff’d, 993 F.2d
1525 (Fed. Cir. 1993) (“[i]t strains reason to conclude that petitioners would fail to accurately
report the onset of their daughter’s symptoms. It is equally unlikely that pediatric neurologists,
who are trained in taking medical histories concerning the onset of neurologically significant
symptoms, would consistently but erroneously report the onset of seizures a week after they in fact
occurred”).

        Accordingly, if the medical records are clear, consistent, and complete, then they should
be afforded substantial weight. Lowrie v. Sec’y of Health & Human Servs., No. 03-1585V, 2005
WL 6117475, at *20 (Fed. Cl. Spec. Mstr. Dec. 12, 2005). Indeed, contemporaneous medical
records are generally 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 & Human Servs., 23 Cl. Ct. 726, 733 (1991), aff’d, 968 F.2d
1226 (Fed. Cir.), cert. denied sub nom. 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”)).

                                                  19
        However, there are situations in which compelling oral testimony may be more persuasive
than written records, such as where records are deemed to be incomplete or inaccurate. Campbell
v. Sec’y of Health & Human 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 & Human
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 & Human
Servs., 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 Health & Human 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 over contrary testimony, 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 & Human 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 Pharmaceuticals,
Inc., 509 U.S. 579, 594–96 (1993). See Cedillo v. Sec’y of Health & Human Servs., 617 F.3d 1328,
1339 (Fed. Cir. 2010) (citing Terran v. Sec’y of Health & Human Servs., 195 F.3d 1302, 1316
(Fed. Cir. 1999)). “The Daubert 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

                                                 20
enjoys general acceptance within a relevant scientific community.” Terran, 195 F.3d at 1316 n.2
(citing Daubert, 509 U.S. at 592–95).

         The Daubert factors play a slightly different role in Vaccine Program cases than they do
when applied in other federal judicial fora (such as the district courts). Daubert factors are usually
employed by judges (in the performance of their evidentiary gatekeeper roles) to exclude evidence
that is unreliable and/or could confuse a jury. In Vaccine Program cases, by contrast, these factors
are used in the weighing of the reliability of scientific evidence proffered. Davis v. Sec’y of Health
& Human 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
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 of his own 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, 618 F.3d at 1347 (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 & Human Servs., No. 08-601V, 2012 WL 3609993, at *17 (Fed. Cl.
Spec. Mstr. July 30, 2012), mot. for review denied, 108 Fed. Cl. 743 (2013), aff’d, 540 F. App’x
999 (Fed. Cir. 2013) (citing Cedillo, 617 F.3d at 1339).

       D.      Consideration of Medical Literature

        Both parties relied on significant amounts of medical and scientific literature to support
their respective positions. I have reviewed all of the medical literature submitted in this case,
although my decision does not discuss each filed article in detail. Moriarty v. Sec’y of Health &
Human Servs., 844 F.3d 1322, 1328 (Fed. Cir. 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).

                                                 21
                                                    ANALYSIS

I.       DTaP Vaccine and Pertussis Toxin Contained Therein

        Before considering whether Petitioner has met his evidentiary burden under Althen, I will
briefly discuss case law pertaining to allegations that the pertussis toxin contained in certain
vaccines can be causal of injury (since Petitioner’s causation theory focuses in part on the
contention that the DTaP vaccine precipitated L.Z.’s first seizures).

        Past Vaccine Program decisions have rejected the notion that the residual amounts of
inactivated/purified pertussis toxin present in the acellular pertussis vaccine can be considered to
cause seizures or encephalopathy to a degree comparable to that of the whole cell version. See,
e.g., Taylor v. Sec’y of Health & Human Servs., 108 Fed. Cl. 807, 820 (2013) (noting that the
modern DTaP vaccine was intended to minimize the amount of toxin in the vaccine as compared
to past versions); Murphy v. Sec’y of Health & Human Servs., No. 05-1063V, 2016 WL 3034047,
at *12 (Fed. Cl. Spec. Mstr. Apr. 25, 2016), mot. for review denied, 128 Fed. Cl. 348 (2016); James
v. Sec’y of Health & Human Servs., No. 09–284V, 2010 WL 4205699, at *11 (Fed. Cl. Spec. Mstr.
Sept. 30, 2010) (acellular form of the pertussis vaccine is much less toxic than the whole-cell
form).

        As such decisions reveal, older medical literature establishing that amounts of toxin
contained in versions of the vaccine previously administered are sufficient to be associated with
seizures or other neurologic injuries cannot be applied wholesale to the version of the vaccine
currently administered. Snyder v. Sec’y of Health & Human Servs., No. 07-59V, 2011 WL
3022544, at *30 (Fed. Cl. Spec. Mstr. May 27, 2011) (explaining that applying DTP-related risk
data to DTaP is a “problematic” and misleading extrapolation); see also Sharpe v. Sec’y of Health
& Human Servs., No. 14-65V, 2018 WL 7625360, at *32 (Fed. Cl. Spec. Mstr. Nov. 5, 2018).
Such claims thus often founder on a petitioner’s inability to establish that the amount of pertussis
toxin that may remain in the acellular form of the vaccine is sufficient to provoke neurologic injury.
Murphy, 2016 WL 3034047, at *12, 33. I keep these sound determinations in mind in assessing
the strength of Petitioner’s evidentiary showing.

II.      Petitioner Has Not Met His Evidentiary Burden of Proof

       I address the Althen prongs relevant and dispositive herein, in order of their significance to
my determination.21
21
   Because Petitioner’s claim fails on the first two Althen prongs, I do not include an extended discussion of the third—
since absent a reliable and persuasive theory of causation, satisfaction of this Althen prong (which considers the
timeframe in which a vaccine is alleged to have caused injury) is an insufficient basis for an entitlement award. Caves
v. Sec’y of Health & Human Servs., No. 07-443, 2010 WL 5557542, at *21–22 (Fed. Cl. Spec. Mstr. Nov. 29, 2010),
mot. for review denied, 100 Fed. Cl. 119 (2011), aff’d, 463 F. App’x 932 (Fed. Cir. 2012). But Petitioner did not
succeed in satisfying this prong either. Although the eight-day period from vaccination to onset of L.Z.’s seizure

                                                           22
         A.       Althen Prong One

        After careful review of the various theories outlined by Dr. Steinman and the evidence he
cites in support for those theories, I find that Petitioner has failed to offer a medically and
scientifically reliable theory for how any of the vaccines L.Z. received could have caused a seizure
disorder.

                  1.       Pertussis Toxin

       The most credible of Petitioner’s proffered theories pertained to the DTaP vaccine. Dr.
Steinman opined that small amounts of the pertussis toxin remaining in the DTaP vaccine could
cause seizures. Steinman Rep. at 6–7; Tr. at 87–98. But this theory relied on a series of
suppositions, not all of which were supported by the filed medical literature or clearly set forth in
persuasive expert testimony.

        First, Dr. Steinman asserted that the acellular pertussis vaccine still contains some amount
of the pertussis toxin. Steinman Rep. at 6 (citing Gomez). Reliable literature supports this
statement. See Gomez at 3311 (noting that “some residual [pertussis toxin] activity may likely be
present” in DTaP “because of the limitations of the detoxification processes used”). However,
Petitioner did not establish what levels of residual toxin would be sufficient to cause injury, or that
the amount found in a DTaP vaccine are of that level, instead assuming instead that any amount
would be enough. The fact that larger amounts contained in the whole cell version of the vaccine
may previously have been determined to be associated with injury does not mean that a version of
the vaccine intended to reduce, if not eliminate, that risk is equally problematic. See, e.g., Murphy,
2016 WL 3034047, at *12. And articles like Gomez say nothing at all about what levels of residual
pertussis toxin are problematic. Gomez at 3312 (purpose of study was to propose more effective
and humane test for determining presence of pertussis toxin).

        Second, Petitioner proposed that the pertussis toxin is associated with an enzymatic process
(ADP-ribosylation). Steinman Rep. at 6. At hearing, however, Dr. Steinman conceded that much
of the literature offered in support of such contentions was outdated. See Steinman Rep. at 6, 9;

disorder is facially reasonable, and consistent with other cases in which vaccines have been found to cause neurologic
harm, Petitioner’s specific explanation for why such a timeframe was medically reasonable in this case was
unpersuasive. Articles like Gomez (which Dr. Steinman discussed at hearing as supporting a seven- to eight-day post-
vaccination onset) did not actually measure the timeframe in which the pertussis toxin component of a DTaP vaccine
would begin to cause seizures (assuming it could do so in the miniscule amounts contained therein). Instead, the
timeframe Dr. Steinman relied on from Gomez related solely to when the HIST process produced mice death after an
intervening factor (histamine challenge). That factor (which is introduced specifically to measure toxin amounts in a
vaccine) has no bearing on how long the pertussis toxin would take by itself to cause neurologic injury, where an
individual received a DTaP vaccine under normal circumstances.

                                                         23
Tr. at 118–19. The more recent literature Petitioner filed was not itself that persuasive for the larger
point it was intended to bulwark. Thus, although Gomez (published in 2007) did somewhat support
Dr. Steinman’s argument, there were limitations to its findings that reduce its overall probative
value. See Gomez at 3317 (noting that pertussis toxin levels for chemically-detoxified DTaP could
not be measured well via ADP-ribosylation enzyme activity).

        Ultimately, however, Dr. Steinman’s theory fails in its most central contention: that
“excessive ADP ribosylation can [. . .] play a neuropathic role leading to seizures and to neuronal
death.” Steinman Rep. at 6. Articles like Gomez do not stand for this proposition; on the contrary,
Gomez showed lower ADP-ribosylase enzymatic activity levels in whole cell pertussis than in
seven of the eight acellular varieties tested, despite the fact that whole cell pertussis contains more
toxin than any detoxified pertussis variety, and has been otherwise more credibly associated with
neurologic damage than the acellular version. Gomez at 3314–15 (finding that “the residual
[pertussis toxin] enzymatic activity in [whole cell DTP] was found to be much lower in comparison
to DTaP products, with the exception of [one DTaP variety]”). Other items of literature cited do
not support the concept that this enzymatic process is harmful, but instead involved experiments
in which seizures were already ongoing or had been induced in some other manner. See Wang at
1285, 1288 (seizures triggered by kainic acid); Chi at 284 (discussing observations relating to
ongoing seizures). Thus, the fact that ADP-ribosylation (or PARP, which Dr. Steinman posited,
without much evidentiary support, was comparable) occurred concurrently with seizures did not
necessarily mean that ADP-ribosylation was responsible for the seizure activity itself. See id. Dr.
Steinman otherwise did not demonstrate that any research he performed in the past relating to
pertussis toxin and the means by which it might be theoretically understood to cause seizure has
been confirmed or corroborated in the past ten years (or longer)—especially in light of the present-
day, widespread use of the acellular version of the vaccine.22

                  2.        RotaTeq and Hib

        The other proposed means by which the vaccines L.Z. received could have caused his
seizures had even less reliable scientific support than Petitioner’s DTaP theory. Thus, to
substantiate his contention that the RotaTeq or Hib vaccines could have caused L.Z.’s seizures,
Dr. Steinman relied almost exclusively on their respective package inserts. Steinman Rep. at 5–6;
Tr. at 81–83. Yet—as Dr. Steinman effectively conceded—the relevant package insert data did not
strongly support his conclusion. The RotaTeq package insert data showing an increased seizure

22
   I also give some weight to Dr. Zempel’s assessment of the persuasiveness of the ADP-ribosylation theory, which
he deemed insufficiently specific and coherent to discuss in depth. See Tr. at 169; Zempel Rep. at 10. However,
because Dr. Zempel did not possess the same level of expertise in immunologic issues as Dr. Steinman, my
determinations on the success of Petitioner’s Althen prong one showing related less to Dr. Zempel’s rebuttal and more
to Petitioner’s ultimate inability (consistent with his burden) to satisfy this prong with preponderant proof arising from
reliable scientific and medical evidence.

                                                           24
incidence is not statistically significant. Tr. at 83–83; Ex. 33 at 6 (noting that “seizures reported as
serious adverse experiences occurred in <0.1% (27/36,150) of vaccine and <0.1% (18/35,536) of
placebo recipients (not significant)”). With regard to Hib, the package insert merely discussed a
study of over five thousand infants in which “two definite and three possible seizures” were noted
after receiving a Hib vaccine concurrently with a DTP vaccine, but concluded that no cause and
effect relationship has been established between the Hib vaccine and seizure. Ex. 34 at 18–19, filed
Aug. 2, 2017 (ECF No. 25-7).23 And even if the data listed on either package insert showed a
stronger association with seizures, package inserts are generally afforded very little weight in
Vaccine Program cases as proof of causation. See, e.g., Christiansen v. Sec’y of Health & Human
Servs., No. 08-244V, 2012 WL 6766650, at *12 (Fed. Cl. Spec. Mstr. Nov. 13, 2012).

                  3.       Alum Adjuvant

        Dr. Steinman’s argument that the alum adjuvant in DTaP may have played a role in causing
L.Z.’s seizures was equally deficient. See Steinman Rep. at 7; Tr. at 98–99. This contention was
supported with almost no reliable medical literature, beyond one item speaking only generally to
the relationship between the immune system and the central nervous system. See generally R. Bhat
& L. Steinman, Innate and Adaptive Autoimmunity Directed to the Central Nervous System, 64
Neuron 123 (2009), filed as Ex. 46, Sept. 6, 2018 (ECF No. 51-9). And I have regularly found
generalized theories about the purported pathogenic role of adjuvants unpersuasive in past Vaccine
Program decisions, absent proof specific to the injury in question or relevant vaccine. See, e.g.,
Johnson v. Sec’y of Health & Human Servs., No, 10-578V, 2016 WL 4917548, at *8–9 (Fed. Cl.
Spec. Mstr. Aug. 18, 2016). The fact that vaccines are known to stimulate cytokine production (in
part due in some cases to the inclusion of an adjuvant) does not amount to a reliable causation
theory that such stimulation is necessarily disease-causing.

        Given the above, I cannot find Petitioner’s proffered causation theories were sufficiently
reliable and persuasive to satisfy Althen prong one.

         B.       Althen Prong Two

        Although Petitioner did not establish a reliable and persuasive causation theory with
sufficient preponderant evidence, his claim would still be unsuccessful even were this not the case,
because the record evidence does not support the conclusion (under the second, “did cause,” Althen

23
  In his written report, Dr. Steinman includes a quote purportedly taken from the Hib package insert that states: “In
Study P3T06, within 30 days following any of Doses 1–3 of DAPTACEL + IPOL + ActHIB 10 vaccines, 50 of 1,455
(3.4%) participants experienced a serious adverse event. One SAE of 11 seizure with apnea occurring on the day of
vaccination with the first dose of the three vaccines 12 was determined by the investigators as possibly related.”
Steinman Rep. at 6. This language does not appear in the document filed as the Hib package insert, however (Ex. 34),
and I do not find the quoted excerpt otherwise clearly demonstrative of an association between the Hib vaccine and
seizures.

                                                         25
prong) that the vaccines L.Z. received on March 24, 2014 likely caused his seizure disorder
beginning on April 1st, approximately eight days later.

        Overall, there are too many factual gaps in the medical record to discern an association
between L.Z.’s vaccinations and his seizures (especially given the sequence of events in this case).
Thus, although seizures can be triggered by a vaccine-induced fever,24 L.Z. unquestionably did not
experience a fever in conjunction with the vaccinations or the first onset of his seizures over a
week later—thereby reducing the likelihood that he was at that time experiencing an underlying
inflammatory event. Ex. 22 at 2522. Indeed, there is no record evidence suggesting that L.Z.
experienced any reaction at all between the March 24th vaccinations and his initial seizures. And,
as explained persuasively by Dr. Zempel, the difference between L.Z.’s MRI reading in April
(which was normal) and May 2014 (which showed substantial brain volume loss) is most likely
attributable to damage caused by refractory status epilepticus seizure activity—not vaccine-
mediated inflammation. Zempel Rep. at 9; Ex. 11 at 47.

       No other testing from L.Z.’s initial hospitalization would confirm Petitioner’s theory,
beyond the evidence of pleocytosis based on CSF measurements taken after his April 2nd
hospitalization. This test result does establish central nervous system inflammation, but it was
obtained only after onset of his seizures. Such a temporal sequence makes it difficult to find it
more likely than not that L.Z. was at that time experiencing a vaccine-caused inflammatory process
(especially since, as the second CSF reading indicated, the pleocytosis appeared ultimately to be
somewhat transient).

        Respondent did propose that L.Z.’s seizures could be associated with preexisting
developmental problems, but the medical record is inconclusive on this point. The unrebutted
evidence of L.Z.’s developmental problems was piecemeal in nature, and its overall probative
value reduced by Dr. Zempel’s concessions that he could not conclude from it that L.Z. was at
high risk for onset of seizures. See, e.g., Ex. 3 at 61–66; Tr. at 211–12. The fact that L.Z. was
referred for developmental services around the time of his vaccinations has not been shown to be
more than temporally coincidental with his seizures (akin to my finding in this case that L.Z.’s
post-vaccination seizures temporally coincided with vaccination). At most, this category of
evidence provided weak weight against Petitione—not enough to tilt the scale against his claim on
its own, but unhelpful to Petitioner given other, more persuasive evidence discussed above.

        Admittedly, Petitioner offered the testimony of one treater, Dr. Siegler, who opined that
L.Z.’s seizures were likely vaccine-caused based on his direct experience with L.Z. Dr. Siegler
was largely a credible witness, who appears to have testified truthfully about his observations in

24
  Vaccine Program precedent recognizes that vaccination may trigger a fever, which in turn can trigger seizures. See,
e.g., Tembenis v. Sec’y of Health & Human Servs., No. 03-2820V, 2010 WL 5164324, at *15–16 (Fed. Cl. Spec. Mstr.
Nov. 29, 2010).

                                                         26
treating L.Z., based on his firsthand knowledge of L.Z.’s medical history. It is well-established
that treater statements have strong probative value—although special masters are not bound by a
treater’s views. See Section 13(b)(1); Snyder, 88 Fed. Cl. at 746 n.67. Dr. Siegler’s testimony is
accordingly entitled to some deference, and it certainly supports Petitioner’s “did cause”
contentions.

        However, several factors lead me to give Dr. Siegler’s testimony less weight than what
Petitioner might urge. First, no contemporaneous treater other than Dr. Siegler seems to have
considered L.Z.’s seizures to have been vaccine-caused.25 Second, Dr. Siegler’s causality views
only came into focus in September of 2016—two and a half years after the first onset of L.Z.’s
seizures, and after this petition was filed. Only then did Dr. Siegler file a VAERS report. While
Dr. Siegler maintained at hearing that in the interim period he had attempted to eliminate other,
more likely causes before considering the possibility of vaccine causation, it is well-established in
the Vaccine Program that contemporaneous medical records—including treater opinions about
possible etiologies—are given more weight than later-in-time statements to the contrary. See
Burns, 3 F.3d at 417. Here, those contemporaneous records memorialize Dr. Siegler’s view in
2014 that Petitioner’s etiology was unlikely to ever be determined. Compare Ex. 11 at 38 with Tr.
at 48–49, 56. Dr. Siegler’s subsequent opinion that L.Z.’s vaccinations produced his seizures loses
some of its probative weight when considered in light of the full medical record (although I also
acknowledge his statement that he revised his opinion only after other etiologies had been
rejected).

        At the same time, Dr. Zempel’s testimony about seizure etiology was probative and
significant. Dr. Zempel persuasively established, based on his extensive experience treating
comparable pediatric patients, that the causes of pediatric seizure disorders often remain unknown,
and that the specific facts of this case did not lead him to consider L.Z.’s vaccines as causal. Zempel
Rep. at 10–11. Although in this case many possible explanations, from an identified viral infection
to an underlying genetic cause, were ruled out, a Vaccine Program petitioner does not succeed in
his claim simply by eliminating other possible causes. Althen, 418 F.3d at 1278; Thomas v. Sec’y
of Health & Human Servs., No. 01-645V, 2007 WL 470410, at *25 (Fed. Cl. Spec. Mstr. Jan. 23,
2007) (citing Grant, 956 F.2d at 1149). Rather, a petitioner must affirmatively, and preponderantly,
establish that the specific vaccine received (whether alone or in series with others) was the cause
of the relevant injury. On the basis of this record, the only conclusion I can reach is that L.Z.’s
seizures were most likely idiopathic. See Bazan, 539 F.3d at 1353 (special master’s finding that a
petitioner’s injury was not vaccine-caused implied that the injury had some other cause, but did
not impermissibly heighten petitioner’s burden of proof by requiring petitioner to eliminate
alternative causes).

25
   In this regard, I take some pause at Dr. Siegler’s relationship to counsel in this case, and the possibility that his
opinion arose out of a desire to support the litigation (see n.13, above). I have nevertheless given careful consideration
to his testimony, and ultimately give it less weight solely due to factors relevant to the medical record, rather than to
the connection between witness and counsel.

                                                           27
        At bottom, Petitioner relied heavily on the eight-day temporal proximity between
vaccination and seizure onset. Indeed, Dr. Siegler characterized this as persuasive proof. Tr. at 56.
But temporal association alone does not suffice to demonstrate causation in the Vaccine Program.
McCarren v. Sec’y of Health & Human Servs., 40 Fed. Cl. 142, 147 (1997). As explained by Dr.
Zempel, “[c]ases of catastrophic epilepsy occur throughout infancy and childhood and will
obviously in some cases have temporal overlap with the timing of vaccination.” Zempel Rep. at
10. While it is clear from the record that L.Z.’s condition changed dramatically and irrevocably
soon after vaccination, this sequence alone is not enough grounds to conclude that his seizures
were likely the result of the vaccines.

                                                 CONCLUSION

        L.Z.’s case is tragic, and Petitioner’s moving testimony made clear that both L.Z. and his
family have been deeply and irrevocably affected by his seizure disorder. In a case such as this—
where a child unquestionably possesses a severe illness, and where the testifying witnesses were
sincere and credible—it is very difficult to resist awarding a petitioner damages. But I am required
to apply the law of the Vaccine Program correctly, rather than based upon my personal sympathies,
and such an application to this case does not lead me to conclude that preponderant evidence
supports Petitioner’s cause of action. I therefore DENY entitlement in this case.

        In the absence of a timely-filed motion for review (see Appendix B to the Rules of the
Court), the Clerk shall enter judgment in accord with this decision.26

         IT IS SO ORDERED.
                                                                         /s/ Brian H. Corcoran
                                                                          Brian H. Corcoran
                                                                          Special Master

26
   Pursuant to Vaccine Rule 11(a), the parties may expedite entry of judgment by filing a joint notice renouncing their
right to seek review.

                                                          28