(222) Anti-NMDA Receptor Encephalitis and Vaccines

Sunday, August 28, 2022

8:00 AM – 1:45 PM CEST

Location: Hall C

Publication Number: 1267

Presenting Author(s)

Thierry Trenque, MD, PhD
– Professor, CHU de Reims, CHU Reims, Reims, Marne, France

Co-Author(s)

Salomé Martin
– Department of Pharmacovigilance and Pharmacoepidemiology, Reims University Hospital, Reims, France., France
Brahim Azzouz
– Department of Pharmacovigilance and Pharmacoepidemiology, Reims University Hospital, Reims, France., France
Federica Tralongo
– Department of Pharmacovigilance and Pharmacoepidemiology, Reims University Hospital, Reims, France., France

Background: Anti-NMDAR encephalitis is an autoimmune neurological disease characterized by the presence in the cerebrospinal fluid (CSF) of antibodies targeting the GluN1 subunit of the N-methyl D-aspartate receptors (NMDAR) in the brain. Incidence is estimated to be 1.5 per million persons per year. The etiology of this type of encephalitis remains largely unknown.

Objectives: The objective of this study is to analyze the potential signals between vaccines and the occurrence of anti-NMDA receptor encephalitis from the global pharmacovigilance database.

Methods: All vaccine-related Individual Case Safety Reports (ICSRs) coded to the MedDRA Lower Level Term (LLT) term "Anti-NMDA receptor encephalitis" and registered in the World Health Organization global database (VigiBase®) up to December 31, 2021 were analysed. A disproportionality analysis was conducted on these cases and the Reported Odds Ratio (ROR) and its 95% confidence interval were calculated for each type of vaccine, according to the coded active substance (active ingredient).

Results: Among the 29,758,737 ICSRs recorded in VigiBase® up to December 31, 2021, 70 cases were coded "Anti-NMDA receptor encephalitis" of which 29 were vaccine-related (females: 56%; median age: 18.2 ± 16.4 years). The three most frequently involved were HPV vaccine (15.7%), Diphtheria/Pertussis/Polio/Tetanus vaccine (15.7%) and Influenza vaccine (13.7%). The three highest ROR were observed with Hepatitis a/Hepatitis b vaccine (78.86 [19.3-321.8]), Rabies vaccine (69.58 [17.1-283.9]) and Typhoid vaccine (55.24 [13.5-225.4]). Covid-19 vaccine (0.57 [0.2-1.6]) and Hepatitis b vaccine (4.06 [0.6-29.3]) did not have significant ROR.

Conclusions: We found a signal between vaccines and anti-NMDAr encephalitis. Clinicians should be informed of this potential risk and encouraged to report any cases of anti-NMDAr encephalitis occurring after vaccine administration.