Cristian Garcia v. HHS - Tdap, anti-N-methyl-D-aspartate receptor encephalitis (2025)

Cristian Garcia, a 26-year-old adult, received a Tdap vaccine on October 2, 2020. Eighteen days later, he experienced a seizure, which marked the onset of his illness.

He subsequently developed worsening confusion and other symptoms, leading to a diagnosis of anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. Mr.

Garcia filed a petition for compensation under the National Vaccine Injury Compensation Program, alleging that the Tdap vaccine caused his condition. The case proceeded as an off-Table claim, meaning Mr.

Garcia had to prove causation. Petitioner's expert, Dr.

Kristen Babinski, proposed several theories for how the Tdap vaccine could cause anti-NMDAR encephalitis, including exacerbation of underlying autoimmune disease, re-stimulation of pre-existing T and B cell clones, and a mechanism involving microRNAs. Respondent's expert, Dr.

Stephen Hedrick, a molecular biologist, contested these theories, arguing that the available data did not support a causal link between the Tdap vaccine and anti-NMDAR encephalitis. He highlighted the low number of reported cases in VAERS and the lack of evidence that the Tdap vaccine could weaken the blood-brain barrier.

After a hearing, the Chief Special Master denied entitlement. The decision found that Petitioner failed to establish a sound and reliable medical theory connecting the Tdap vaccine to anti-NMDAR encephalitis (Althen prong one) and did not demonstrate a logical sequence of cause and effect showing the vaccine caused the injury (Althen prong two).

The court later denied Petitioner's motion for review, affirming the Special Master's decision. Mr.

Garcia was not compensated.