Davenport v. Secretary of Health and Human Services

In the United States Court of Federal Claims OFFICE OF SPECIAL MASTERS ************************* ROSS DAVENPORT, * * No. 19-820V Petitioner, * Special Master Christian J. Moran * v. * * Filed: August 24, 2026 SECRETARY OF HEALTH * AND HUMAN SERVICES, * * Respondent. * ************************* Jessica Olins and Leeanne Pedrick, MCT Law, Seattle, WA, for petitioner; Sara DeStefano and Alyssa Petroff, United States Dep’t of Justice, Washington, DC for respondent. PUBLISHED DECISION DENYING ENTITLEMENT TO COMPENSATION 1 Ross Davenport received a vaccination against Streptococcus pneumoniae called Prevnar and then developed a neurologic disorder called Guillain-Barré syndrome (“GBS”). 2 Through this claim in the National Childhood Vaccine Injury Compensation Program, Mr. Davenport alleges that Prevnar caused his GBS. He supported his claim with reports from a neurologist whom he retained, Kazim A. Sheikh. His attorneys later advocated through a brief. The Secretary opposed compensation. The Secretary relied upon two experts he retained. The first is a neurologist, Dara G. Jamieson. The second is a Ph.D. immunologist, who is not a 1 Because this decision contains a reasoned explanation for the action taken in this case, it must be made publicly accessible and will be posted on the United States Court of Federal Claims’ website, and/or at https://www.govinfo.gov/app/collection/uscourts/national/cofc, in accordance with the E-Government Act of 2002. 44 U.S.C. § 3501 note (2018) (Federal Management and Promotion of Electronic Government Services). This means the decision will be available to anyone with access to the internet. In accordance with Vaccine Rule 18(b), the parties have 14 days to identify and move to redact medical or other information, the disclosure of which would constitute an unwarranted invasion of privacy. Any changes will appear in the document posted on the website. 2 An explanation of some medical terms is found in the appendix. Given that the experts discussed relatively complicated medical subjects, the experts on both sides are encouraged to provide more background information in future cases. Likewise, the attorneys are encouraged to explain medical information in their briefs. 1 medical doctor, Ross M. Kedl. The Secretary, too, advocated through a brief. A hearing was held during which Mr. Davenport and the three retained experts testified. A review of the record reveals that Mr. Davenport has not met his burden to show that Prevnar caused his GBS. As discussed below, he has not presented a reliable theory to explain how Prevnar can cause GBS. I. Medical History Mr. Davenport was born in 1952. Tr. 17. Until around 2016, Mr. Davenport worked for the city of Spokane, Washington as a supervisor for managing solid waste. Tr. 18. When he was employed, he usually commuted to work by riding his bicycle 12.5 miles each way. Tr. 19. In retirement, Mr. Davenport continued his active lifestyle. He often rode his bicycle, and he liked to ski. He exercised at a local YMCA. Tr. 18-19. He did not have any limitations on his mobility. Tr. 20. In the litigation, the Secretary has not contended that any health problem from before the vaccination contributed to Mr. Davenport’s GBS. See Resp’t’s Rep., filed Aug. 11, 2020, at 5. When Mr. Davenport became eligible for Medicare, he had a general wellness examination. The doctor gave him a clean bill of health. Tr. 20; see also Exhibit 1 at 304-08 (Apr. 17, 2018). During this appointment, Mr. Davenport received a dose of Prevnar. 3 Prevnar is a vaccine that protects against strains of the streptococcus pneumoniae bacteria. Tr. 60. Prevnar is sometimes referred to as “Prevnar 13” because this vaccine protects against 13 different strains. Tr. 219. Prevnar does not contain any live bacteria. Tr. 162. A few days after the vaccination, Mr. Davenport was visiting a casino in Idaho. His legs did not feel correct and he could not sit at a slot machine. So, his wife drove home. Tr. 21. After this, his symptoms progressed. He developed back pain, numbness and weakness in his arms, and intermittent numbness in his legs. He told his primary physician about these problems on May 2, 2018. The doctor obtained an MRI, which revealed spinal stenosis and disc bulging. Exhibit 1 at 351; see also Tr. 22. The doctor sent Mr. Davenport home. The next day, Mr. Davenport was not any better. His legs were not working and he fell. Weakness prevented him from gripping anything. When his wife communicated these symptoms to the doctor, the doctor advised Mr. Davenport to go to the emergency department. Exhibit 1 at 367; see also Tr. 23. In the first hospital, Mr. Davenport spent many hours in the emergency department waiting to be seen. Tr. 23. He underwent a lumbar puncture. Exhibit 2 at 48. The doctors again sent Mr. Davenport home. Tr. 24. When Mr. Davenport arrived home, he fell backwards, going up the steps leading into his house. Mr. Davenport managed to crawl to a couch, where he slept. Tr. 24. The next morning, 3 Mr. Davenport also received the hepatitis B vaccine and a typhoid vaccine. However, these other vaccines are not the basis for his claim for compensation. 2 Mr. Davenport could not get out of bed and his wife called an ambulance, which brought him to a different hospital. He was admitted to Sacred Heart Hospital, where he stayed for approximately 18 days. Tr. 27. During this admission, Mr. Davenport underwent an EMG. The results were consistent with acute motor axonal neuropathy (AMAN). Exhibit 4 at 27. The neurologists retained in this litigation agree that AMAN is the appropriate diagnosis for Mr. Davenport. Exhibit A at 12; Exhibit 70. Acute Motor Axonal Neuropathy AMAN is a subtype of Guillain-Barré syndrome. GBS is a term that encompasses different types of neurologic disorders. The most common subtype of GBS is known as acute inflammatory demyelinating polyneuropathy, often abbreviated “AIDP.” Because AIDP is much more prevalent in the United States, the term GBS is sometimes used synonymously with AIDP but this is not correct. Tr. 156. As its name indicates, in AMAN, nerve motor axons are impaired. By way of contrast, in AIDP, the myelin is attacked. Tr. 55-56. As discussed later in this opinion, the testifying experts have some differences of opinion as to whether what is known about AIDP can be transferred to AMAN. During his stay at Sacred Heart Hospital, Mr. Davenport received treatment for AMAN, including receiving five doses of intravenous immunoglobulin. The details of the treatment for AMAN are generally not relevant to determining whether the Prevnar vaccine caused Mr. Davenport’s AMAN. For more information, see Pet’r’s Br. at 3; Resp’t’s Br. at 3. While in Sacred Heart, a neurologist, Ruxandra Costa, evaluated Mr. Davenport. Exhibit 4 at 156 (May 4, 2018). Dr. Costa suspected that Mr. Davenport was suffering from the AMAN form of GBS. She also wrote: “this can be related to the pneumonia shot especially if this used any live-attenuated type of strains.” Id. at 158. The doctor who discharged Mr. Davenport from Sacred Heart stated that Mr. Davenport’s AMAN was “[p]ossibly triggered by Prevnar 13–was given to patient 2 w[ee]ks prior [to] admission.” Id. at 13; accord Tr. 55. After he was discharged from Sacred Heart, Mr. Davenport went to St. Luke’s Rehabilitation Institute. Tr. 28; see also Exhibit 3. With assistance from the rehabilitation specialists, Mr. Davenport improved so that he no longer required a wheelchair. Tr. 29. Mr. Davenport continued to exercise for the next three years. In the intervening years, Mr. Davenport’s doctors expressed some concern that Prevnar may have caused his AMAN. See, e.g., Exhibit 5 at 3 (Sep. 25, 2018); Exhibit 18 at 11 (Oct. 27, 2020). One doctor exempted Mr. Davenport from receiving the Covid vaccine as a condition for travel. Exhibit 48 at 20 (May 25, 2021). Yet, this same doctor also recommended that Mr. Davenport receive the Covid vaccine. Id. at 8. When Mr. Davenport testified in 2025, he stated that he was not in much pain. Leg cramps can interfere with his sleeping, but he did not want to take medicine. Tr. 31. He does not ride his bicycle and has not gone skiing since the original episode. Mr. Davenport seemed 3 determined to maintain a relatively positive attitude. In his words, he was “still kicking, just not as high.” Tr. 33. II. Procedural History Mr. Davenport’s case took more twists and turns than a typical case in the Vaccine Program. These various steps are explained in the succeeding sections. A. Initial Materials Represented by an attorney at Maglio, Christopher & Toale, Mr. Davenport initiated this case by filing a petition on June 4, 2019. As noted previously, Mr. Davenport alleges that Prevnar caused him to suffer AMAN. He quickly submitted medical records. The Secretary reviewed this material and advised against an award of compensation. Resp’t’s Rep., filed pursuant to Vaccine Rule 4 on Aug. 11, 2020. The Secretary argued that Mr. Davenport did not meet his burden of proof, noting, in part, that Mr. Davenport had not presented a report from an expert. Because it appeared likely that the parties would retain reports from people retained for this litigation, a set of Expert Instructions was proposed. After the parties did not object, the instructions became final. B. Experts and Their Reports Each party filed reports from two people. Mr. Davenport submitted reports from a neurologist, Dr. Sheikh, and a pediatric immunologist / dermatologist, Marc Serota. However, as discussed below, Mr. Davenport eventually withdrew Dr. Serota’s reports, leaving only reports from Dr. Sheikh. The Secretary retained Dr. Jamieson and Dr. Kedl. 1. Dr. Sheikh and his First Report Dr. Sheikh attended undergraduate college and medical school in Pakistan. He came to the United States in 1990 to participate in an internship, residency, and then a fellowship in neurology. He became board-certified in neurology in 1998. Exhibit 129 (curriculum vitae). Dr. Sheikh teaches at the University of Texas, Houston. In that role, he lectures about GBS and how vaccines might cause GBS via molecular mimicry. Tr. 48-49. Dr. Sheikh directs a GBS / CIDP Center for Excellence. Tr. 48. He obtained this role by applying to the GBS / CIDP Foundation. Tr. 134. For many years, Dr. Sheikh assisted the GBS / CIDP Foundation. He served on the committee that reviews applications for grants to the GBS / CIDP Foundation and acted as chair of that committee. To Dr. Sheikh’s awareness, this committee has not received any proposals to investigate whether Prevnar causes GBS. He is not sure whether the Foundation would fund this research. Tr. 108-12. Although he sometimes works with immunologists (see Tr. 48, 135), Dr. Sheikh is not an immunologist. As the Secretary brought out on cross-examination, Dr. Sheikh does not have a Ph.D. in immunology. Tr. 94. 4  Dr. Sheikh disclosed a series of opinions in his first report, which was filed on May 17, 2021. He opined that Mr. Davenport suffered from GBS, without specifying a subtype. Exhibit 19. To explain how Prevnar could cause GBS, Dr. Sheikh relied upon the theory of molecular mimicry. Id. at 6. He presented three variations on the theme of molecular mimicry. In the first, components of Prevnar resemble portions of peripheral nerves known as galactose and gangliosides. In the context of this first theory, Dr. Sheikh cited three articles. Id. at 9-10. In the second variation of molecular mimicry, Dr. Sheikh linked a protein in Prevnar (CRM197) to peripheral nerve protein P0. Id. at 10. In the third variation, Dr. Sheikh discussed adjuvants. Id. at 10. 2. Dr. Jamieson and her First Report Dr. Jamieson earned her undergraduate degree at George Washington University, majoring in zoology and physics. She then went on to obtain her M.D. from the University of Pennsylvania School of Medicine in 1982. Exhibit J. Afterwards, she completed a neurology residency and a fellowship in cerebrovascular disease at the hospital at the University of Pennsylvania. Tr. 149. Dr. Jamieson held various academic positions over the following years, and is presently the Clinical Associate Professor of Neurology at Weill Cornell Medicine, New York Presbyterian Hospital. Exhibit J; Tr. 150. She has held this position since 2005. Although she no longer sees patients as of June 2018, she retained her academic position and teaches medical students, residents, fellows, and attendings. Tr. 150. Dr. Jamieson was formerly the president of the American Society of Neuroimaging and of the Philadelphia Neurological Society. Tr. 150. She is a member of the American Academy of Neurology and teaches courses and gives lectures at their annual meetings. Id. Additionally, Dr. Jamieson participates in editing and peer-reviewing for various journals. Id. at 150-51. In her first report, Dr. Jamieson discussed GBS and its various subtypes, including AIDP and AMAN. Exhibit A at 7-8. Dr. Jamieson asserted that “Dr. Sheikh’s arguments used to link Mr. Davenport’s acute neuropathic process with his preceding pneumococcal vaccination refer[] to ‘GBS’ and do not distinguishing between AIDP and AMAN. These two distinct entities, with different nerve tissue pathologies and biomarkers, are thus conflated in Dr. Sheikh’s assessment of the reports examining GBS in the context of vaccination.” Id. at 11. Dr. Jamieson stated that Mr. Davenport met the diagnostic criteria for AMAN within about two weeks of the vaccination. Id. at 12. Dr. Jamieson disagreed with the opinion that Prevnar can cause GBS. She relied upon epidemiologic studies, which are discussed below. Exhibit A at 8-11. She concluded: “More likely than not Mr. Davenport’s development of GBS/AMAN was coincidental to his receipt of Prevnar 13 vaccine, but the two events were not causally related.” Id. at 13. 5  3. Dr. Kedl and his First Report 4 After earning a Bachelor of Science in biology, Dr. Kedl obtained a Ph.D. in pathobiology from the University of Minnesota Medical School in 1997. For about three years, he worked for 3M Pharmaceuticals as a senior immunologist. Tr. 282-84. In 2004, Dr. Kedl started an academic career at the University of Colorado. Currently, he is a full professor in the Department of Immunology and Microbiology. In this role, he teaches at the medical school, which is not proximate to the undergrad campus. Tr. 284. He teaches graduate students and medical students about immunology and vaccination. Tr. 211, 284-85. Dr. Kedl’s research focuses on T cells. A particular interest is whether T cells can be used to fight cancer. Tr. 211. Due to his expertise in how T cells are generated, he has often served on advisory committees studying the effectiveness of adjuvants in the context of vaccines. Tr. 212. During the hearing, Dr. Kedl was recognized as an expert in immunology. Tr. 215. As pointed out during cross-examination, Dr. Kedl has not worked on neuro-inflammatory conditions specifically. Tr. 257. Dr. Kedl’s first report challenged many opinions from Dr. Sheikh about how Prevnar can cause GBS. A particular point of disagreement was the reliability of molecular mimicry. Dr. Kedl agreed with Dr. Sheikh’s assertion that “Molecular mimicry has historically been held as a favored mechanistic explanation for the induction of autoimmunity.” Exhibit B at 4. But, in Dr. Kedl’s view, “this model no longer maintains scientific plausibility.” Id. Dr. Kedl’s first report brought out criticisms of the molecular mimicry theory, which recur throughout the case. Dr. Kedl asserted that molecular mimicry appears to assume that similarities between vaccines and host tissues must be rare. If they were common, then many cross-reactions would occur. However, according to Dr. Kedl, similarities in structures are actually very common. Exhibit B at 11-13 (using CRM197 as an example). Dr. Kedl also opined that any similarity must be biologically relevant, meaning that it can independently contribute to a disease’s pathology. Dr. Kedl followed this reasoning in explaining what (to him) are the deficits in Dr. Sheikh’s attempt to connect Prevnar with gangliosides. Dr. Kedl asserted that “no ganglioside- specific antibodies have ever been observed in response to the Prevnar vaccine, either in animal models or clinically.” Exhibit B at 16. Dr. Kedl observes that the substances that Dr. Sheikh identified as being critical in the pathogenesis of Prevnar-induced GBS are also present in other human tissues. Yet, these tissues seem not to be the subject of an immune-mediated attack. Id. at 16-17. Dr. Kedl highlighted that vaccines, themselves, demonstrate the lack of cohesion in the theory of molecular mimicry because the components of the flu vaccine change each year. If structural similarity were sufficient, then varying the flu vaccine’s strains would be unnecessary. Id. at 18. 4 Information about Dr. Kedl’s background can be found in his updated curriculum vitae. Exhibit I. 6  In addition to challenging molecular mimicry as a general proposition and as used to explain how Prevnar could cause GBS, Dr. Kedl also discussed epidemiology. In Dr. Kedl’s view, epidemiology weighs against finding an association. While Dr. Sheikh had opined that epidemiological studies may not detect rare events, Dr. Kedl pointed to the discovery that people given the AstraZeneca Covid vaccination had an increased risk of heparin-induced thrombotic thrombocytopenia at a rate of 1:1,000,000. Exhibit B at 5. Thus, it is not sufficient in Dr. Kedl’s eyes for Dr. Sheikh to dismiss the epidemiologic studies, such as Baxter and Tseng, which are discussed below. 4. Marc Serota and His Report In January 2022, Mr. Davenport’s attorney of record became Jessica Olins, and since that time, she has represented him. When represented by Attorney Olins, Mr. Davenport obtained a report from Dr. Serota. He is board-certified in “allergy/immunology, dermatology and pediatrics.” Exhibit 69 (report) at 1. Dr. Serota generally supported Dr. Sheikh’s proposal that molecular mimicry can explain how Prevnar can cause GBS. 5. Dr. Sheikh’s Second Report Via a report filed on May 16, 2022, Dr. Sheikh responded to the opinions presented by Dr. Jamieson and Dr. Kedl. Although Dr. Jamieson noted that Dr. Sheikh had not differentiated AIDP from AMAN, Dr. Sheikh’s second report focused on AMAN. In doing so, Dr. Sheikh recognized that his second way of linking Prevnar to GBS, which was through P0, a major protein in myelin, “is less relevant to [the] AMAN form of GBS.” Exhibit 70 at 10. A significant portion of Dr. Sheikh’s second report was devoted to addressing Dr. Kedl’s question about why the antibody-mediated attack is restricted to nerves when gangliosides are distributed across the human body widely. Dr. Sheikh agreed “this is an important and relevant question.” Id. at 3. Dr. Sheikh admitted that “this is a complicated multifaceted issue and not all aspects related to it are completely worked out.” Id. Nevertheless, based upon various articles cited below, Dr. Sheikh opined that it is possible for antibodies to attack only certain nerve tissues. Id. at 3-10. Dr. Sheikh also presented a defense of the theory based on alum in about one page. Id. at 15. Finally, Dr. Sheikh maintained that epidemiologic studies cannot be applied to any individual. Because of Prevnar’s overall record of safety, he advises his patients to get Prevnar. Id. at 16-17. 6. Dr. Jamieson’s Second Report Dr. Jamieson’s next report was relatively short, approximately 3.5 double-spaced pages. She maintained her opinion that despite Dr. Serota’s first report and Dr. Sheikh’s second report, “Mr. Davenport’s development of GBS/AMAN was coincidental to his vaccination with Prevnar 13, without a causal relationship.” Exhibit E at 4. 7  7. Dr. Kedl’s Second Report Dr. Kedl continued to challenge the reliability of molecular mimicry as a theory. As he had previously done with flu vaccines, Dr. Kedl pointed out that with Prevnar, “one strain does not produce biologically meaningful cross-reactive immunity to other strains, despite structural similarities that are orders of magnitude better than any they may possess with mammalian gangliosides.” Exhibit F at 3. He went so far as to state: “Molecular mimicry proponents should be open to critique about the perceived supremacy of this outdated model. If science is to move forward, questioning the authority of 30-year-old sacred cows is a necessary step in its pursuit.” Id. 5 As to Dr. Sheikh’s explanation of why antibodies would attack only gangliosides in peripheral nerves, Dr. Kedl stated Dr. Sheikh has shown “what some antibodies against gangliosides can do, but they are fraught with complications when trying to conclude what the normal repertoire of antibodies actually does do.” Exhibit F at 4 (emphasis in original). Dr. Kedl also emphasized “no ganglioside-specific antibodies have been documented in response to the Prevnar vaccine, either in animal models or clinically.” Id. at 2 (emphasis removed). This report was the final report. See Pet’r’s Status Rep., filed Dec. 18, 2022 (declining to present additional reports from either Dr. Serota or Dr. Sheikh). Accordingly, the parties were directed to argue their positions via briefs. Order, issued Feb. 24, 2023. C. Briefs Mr. Davenport claimed that he was entitled to compensation. Pet’r’s Br., filed Aug. 4, 2023. The brief discussed the qualifications of both people he had retained, Dr. Serota and Dr. Sheikh. Id. at 9-12. Otherwise, the brief did not rely upon opinions from Dr. Serota. In terms of theories to explain how Prevnar can cause AMAN, Mr. Davenport advanced the three theories from Dr. Sheikh. These are (1) a ganglioside / galactose theory, (2) a CRM197-P0 theory, and (3) a theory involving adjuvants. Pet’r’s Br. at 70-91. Mr. Davenport also argued against giving much weight to the epidemiologic studies. Id. at 91-94. In closing, Mr. Davenport stated that he was “amenable” to a ruling on the papers without oral testimony. Id. at 103. The Secretary contended that Mr. Davenport was not entitled to compensation. Resp’t’s Br., filed Oct. 13, 2023. The Secretary, too, did not oppose a ruling on the record. The Secretary argued that his experts were better qualified to opine on the topics relevant to adjudicating Mr. Davenport’s claim for compensation. Resp’t’s Br. at 15-18. In doing so, the Secretary described Dr. Serota as an “attending dermatologist.” Id. at 16 (citing Dr. Serota’s updated curriculum vitae). The Secretary further asserted that for Dr. Serota, “respondent was unable to find any education, training, or experience meaningfully relevant to the medical issues in this case.” Id. at 17. Thus, the Secretary largely did not respond to Dr. Serota and, instead, addressed the theories offered by Dr. Sheikh. 5 In his oral testimony, Dr. Kedl characterized this statement as “hyperbole.” Tr. 294. 8  In opposing the theories from Dr. Sheikh, the Secretary began with a discussion of epidemiology. Id. at 19-22. To the Secretary, epidemiology was more valuable than a single case report Dr. Sheikh cited. The Secretary also addressed the three theories that Mr. Davenport had advanced. Id. at 22-28. With respect to the theory based on alum, the Secretary noted that this portion of Dr. Sheikh’s second report was extremely similar to a portion of report submitted by a different expert in another case, Lawrence Steinman. The Secretary recommended clarification. Id. at 27 n.12. After the Secretary argued against compensation, the time for submitting a reply surprisingly lapsed without the submission of any brief from Mr. Davenport. D. Preparation for a Hearing A review of the materials suggested that oral testimony was appropriate. Order, issued May 24, 2024. One reason was that the undersigned had not adjudicated any cases in which petitioners had asserted that Prevnar can cause GBS. In preparation for the hearing, Mr. Davenport was required to obtain an affidavit from Dr. Sheikh regarding the alum portion of his second report. Mr. Davenport was also required to explain whether he was relying upon reports from Dr. Serota. 6 For the question about the authorship of the portion of the report on alum, Dr. Sheikh declared that he had spoken with Dr. Steinman about this topic. Exhibit 120 (Dr. Sheikh’s affidavit). Likewise, Mr. Davenport procured an affidavit from Dr. Steinman in which Dr. Steinman averred that he had spoken to Dr. Sheikh about alum. Exhibit 119 (Dr. Steinman’s affidavit). For Dr. Serota, Mr. Davenport stated that “Petitioner revised his litigation strategies and will now primarily rely on Dr. Sheikh’s reports.” Pet’r’s Status Rep., filed June 25, 2024. A status conference was held to discuss these issues. With respect to the controversy over the authorship of the alum portion, the Secretary was not satisfied with the disclosures from Dr. Sheikh and Dr. Steinman. The Secretary proposed that because it appeared that Dr. Sheikh lacked sufficient expertise in this area, the alum-based theory be removed from the case. In response, Mr. Davenport agreed to remove the alum-based theory. See Morrison v. Sec’y of Health & Hum. Servs., No. 18-386V, 2024 WL 3738934, at *8 n.8 (Fed. Cl. Spec. Mstr. July 18, 2024) (noting that in a case in which an attorney from the same law firm as representing Mr. Davenport declined to pursue a theory based upon alum). On the topic of Dr. Serota’s continued participation, Mr. Davenport’s position was unclear. Counsel for Mr. Davenport reported that communicating with Dr. Serota was difficult. Counsel seemed interested in keeping the literature Dr. Serota cited in the record regardless of whether Dr. Serota testified. The undersigned explained that ordinarily, experts should be 6 The Secretary also was directed to submit a summary of the articles on which he was relying, which the Secretary’s October 13, 2023 brief had neglected to do. The Secretary did so on July 8, 2024. 9 prepared to answer questions orally about the opinions they have expressed in writing. To the extent that Dr. Sheikh wished to rely upon articles that Dr. Serota had cited, Dr. Sheikh must disclose his own opinion about the articles. Order, issued July 9, 2024. Mr. Davenport presented his positions in a status report filed on August 8, 2024. He requested that his case be adjudicated on the papers. This request was surprising because it would seem that petitioners would prefer an opportunity to demonstrate the persuasiveness of their expert’s opinions through oral testimony. Regardless, the parties were given an opportunity to discuss whether the hearing should be held in-person at a remote location or via videoconferencing. Order, issued Aug. 20, 2024. With respect to Dr. Serota, Mr. Davenport proposed striking his report. Pet’r’s Status Rep., filed Aug. 8, 2024. He was afforded an opportunity to discuss with Dr. Sheikh whether Dr. Sheikh wanted to rely upon articles that Dr. Serota had cited. Order, issued Aug. 20, 2024. Dr. Sheikh identified the articles on which he wanted to rely. Exhibit 121. After receiving information from the parties, a hearing was scheduled to take place in Denver, Colorado from August 28-29, 2025. Order, issued Nov. 6, 2024. The parties were given an opportunity to submit any additional medical articles before the hearing. However, due to budget limitations at the Office of Special Masters, travel to Denver was not possible. Thus, the parties were directed to express whether they preferred bringing their witnesses to Washington, DC or conducting the hearing via videoconferencing. Order, issued June 12, 2025. In preparation for the hearing, the undersigned asked the parties a series of questions. The undersigned stated that Mr. Davenport was advancing a theory based upon gangliosides and glycolipids, which the undersigned labeled as theory 1(a) and theory 1(b). Mr. Davenport was also advancing a theory based upon a component of myelin, P0, although Mr. Davenport suffered from a disorder of his axons. Thus, the parties were expected to comment. Order, issued July 3, 2025. On the day this order issued, Mr. Davenport announced that Dr. Sheikh was not available for the hearing, which the November 6, 2024 order had scheduled for August 28-29, 2025. Dr. Sheikh had “an unforeseen and pressing family matter.” Pet’r’s Mot., filed July 3, 2025. As remedy, Mr. Davenport proposed transferring the case to another special master. The basis for this request was not evident. In any event, after conferring with the chief special master, this request was denied. Order, issued July 7, 2025. Another status conference was held on July 29, 2025. The parties agreed to present their witnesses through videoconferencing at a hearing on November 13-14, 2025. Mr. Davenport withdrew his reliance on a theory involving P0. Thus, Mr. Davenport was proceeding only on the theory involving gangliosides and glycolipids. Order, issued July 30, 2025. For this theory, the parties agreed that although this theory had been presented to other special masters, special masters had not evaluated the merit of this theory. See Brown v. Sec’y of Health & Hum. Servs., No. 18-1074V, 2025 WL 2017882, at *25, *27 (Fed. Cl. Spec. Mstr. June 23, 2025); Bartoszek v. Sec’y of Health & Hum. Servs., No. 17-1254V, 2024 WL 4263604, at *9 (Fed. Cl. Spec. Mstr. Aug. 27, 2024). 10  With the removal of the theories involving alum and P0, the case was narrowed to an assessment of the ganglioside and glycolipid theory. The undersigned attempted to identify components of the theory on which the parties agreed and on which the parties differed. Order, issued Nov. 5, 2025. This attempt was largely successful. See Jt. Status Rep’t, filed Nov. 10, 2025. With the clarifications from the parties, the ganglioside / glycolipid theory can be divided into the following components: Part Aspect Pet’r’s Assertion Resp’t’s Response Prevnar contains some strains that contain 1 Structural Not disputed galactose residues that are terminal. 2 Structural Myelin contains gangliosides. Not disputed Some gangliosides in myelin and axons contain a 3 Structural Not disputed terminal galactose residue. In responding to Prevnar, the human immune 4 Immunologic system sees galactose residues and develops an Disputed immune response to the galactose residues. Anti-galactose antibodies (or anti-ganglioside Immunologic antibodies) produced in response to Prevnar go to 5 Disputed / Neurologic the peripheral nervous system to attack gangliosides in myelin and axons, causing AMAN. E. Hearing The parties presented oral testimony at a hearing on November 13-14, 2025, which was conducted by videoconferencing. Mr. Davenport testified. He made a favorable impression as a person who was healthy before receiving Prevnar. He movingly explained how AMAN has affected his life. For someone who had suffered greatly, his outlook was refreshingly positive. Dr. Sheikh testified. Although Dr. Sheikh had written reports in the Vaccine Program since approximately 2014 (Tr. 114), this occasion was his first time testifying orally. Tr. 95. Before testifying, Dr. Sheikh met with Mr. Davenport’s attorneys four times. Each session to prepare Dr. Sheikh’s testimony lasted approximately two or two and a half hours. Tr. 116. Dr. Sheikh’s demeanor while testifying may have reflected his lack of experience in testifying. His testimony, particularly on direct examination, came across as overly regimented / scripted. By way of contrast, his relatively short rebuttal testimony appeared much more spontaneous. The undersigned anticipates that as Dr. Sheikh takes the witness stand more frequently, his ability to present his opinions persuasively will increase. In this regard, Dr. Sheikh should also learn from the experience regarding the alum theory. Dr. Sheikh should not have taken about a page from another expert’s report without crediting the original expert. See Raymo v. Sec’y of Health & Human Servs., No. 11-0654V, 2014 WL 1092274, at *13-14 (Fed. Cl. Spec. Mstr. Feb. 24, 2014) (discussing plagiarism). Dr. Sheikh would have made a better impression if this controversy had not developed. After Dr. Sheikh finished his oral testimony, the Secretary called both his experts. Dr. Jamieson was generally fine. During cross-examination on two occasions, she was asked her opinions about immunologic topics. Tr. 179-80. She answered that she was deferring to Dr. 11 Kedl. This deferral seemed inappropriate as Mr. Davenport’s attorney was probing the limits of Dr. Jamieson’s opinions. 7 Of the three testifying professionals, Dr. Kedl made the most favorable impression. He explained complicated topics in a way that made them understandable. 8 Following the hearing, the parties were not directed to argue their cases through post- hearing briefs. Thus, with the completion of testimony, the case is ready for adjudication. III. Standards for Adjudication A petitioner is required to establish his case by a preponderance of the evidence. 42 U.S.C. § 300aa–13(1)(a). The preponderance of the evidence standard requires a “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 v. Sec’y of Health & Hum. Servs., 592 F.3d 1315, 1322 n.2 (Fed. Cir. 2010) (citations omitted). Proof of medical certainty is not required. Bunting v. Sec’y of Health & Hum. Servs., 931 F.2d 867, 873 (Fed. Cir. 1991). Distinguishing between “preponderant evidence” and “medical certainty” is important because a special master should not impose an evidentiary burden that is too high. Andreu v. Sec’y of Health & Hum. Servs., 569 F.3d 1367, 1379-80 (Fed. Cir. 2009) (reversing special master's decision that petitioners were not entitled to compensation); see also Lampe v. Sec’y of Health & Hum. Servs., 219 F.3d 1357 (Fed. Cir. 2000); Hodges v. Sec’y of Health & Hum. Servs., 9 F.3d 958, 961 (Fed. Cir. 1993) (disagreeing with dissenting judge's contention that the special master confused preponderance of the evidence with medical certainty). IV. Elements of a Petitioner’s Claim To receive compensation, a petitioner must establish five elements. 42 U.S.C. § 300aa– 11(c)(1)(A) through (E); 42 U.S.C. § 300aa–13(a)(1)(A) (authorizing special masters to award compensation when petitioners establish items listed in section 11(c)(1)). Often a critical element is causation, which is found in paragraph (C) of 42 U.S.C. § 300aa–11(c)(1). When a petitioner seeks compensation for a claim not based upon the Vaccine Injury Table (like Mr. Davenport here), a petitioner is not entitled to a presumption of causation. Instead, a petitioner bears the burden of showing that the vaccine was the cause-in-fact for his injury. For causation-in-fact cases, the Federal Circuit has defined components of a petitioner’s burden. Petitioners bear a burden “to show by preponderant evidence that the vaccination 7 Mr. Davenport’s attorney appeared to accept Dr. Jamieson’s deferral to Dr. Kedl. The attorney did not seek an order requiring Dr. Jamieson to answer the questions. 8 Between the pre-trial conference and the hearing, Dr. Kedl created a demonstrative exhibit with information about enzymes from the Human Atlas Protein website and Mr. Davenport objected to its use. Tr. 9-12. A problem with the proposed demonstrative was that Dr. Kedl had not disclosed any opinions with respect to enzymes. See Tr. 199-202. The Secretary withdrew the demonstrative exhibit. Tr. 209. 12 brought about [the vaccinee’s] injury by providing: (1) a medical theory causally connecting the vaccination and the injury; (2) a logical sequence of cause and effect showing that the vaccination was the reason for the injury; and (3) a showing of a proximate temporal relationship between vaccination and injury.” Althen v. Sec’y of Health & Hum. Servs., 418 F.3d 1274, 1278 (Fed. Cir. 2005). V. Analysis—Althen Prong One Relevant evidence concerning the general topic of whether Prevnar can cause GBS falls into two broad categories. The first category (discussed in section A, below) concerns the theory that Dr. Sheikh advances, molecular mimicry. The second category (discussed in section B, below) concerns literature, such as epidemiologic studies, that discuss the topic. Another type of literature is case reports. Section C contains a short conclusion. Section D touches upon the remaining Althen prongs. A. Molecular Mimicry 1. Introduction Molecular mimicry is often advanced by petitioners in the Vaccine Program. Hoffman v. Sec’y of Health & Human Servs., No. 19-111V, 2024 WL 4444773 (Fed. Cl. Spec. Mstr. Sep. 13, 2024) (listing cases in appendices). At a basic level, molecular mimicry is a theory that can be reduced to two parts: (a) a similarity between components of an antigen, such as an infectious agent or a vaccine, and host tissue, and (b) a pathologic cross-reaction. Tr. 63, 222; see also Pet’r’s Br. at 45; Exhibit 19 at 9; Exhibit B at 9. 9 By way of background, molecular mimicry was first proposed in the early 1980’s. Tr. 66. Dr. Sheikh’s first report cited three articles published in 1998-2005. Exhibit 19 at 6; see also Tr. 96-97; Romine v. Sec’y of Health & Human Servs., No. 19-468V, 2026 WL 937898, at *9 (Fed. Cl. Spec. Mstr. Mar. 13, 2026). As discussed below, in light of sci