Encephalitis after Vaccination in United States. A Report from the CDC/FDA Vaccine Adverse Event Reporting System. [1990–2010] (P03.151)

Abstract

Objective: To determine the rates and characteristics of encephalitis after administration of vaccination in The United States.

Background There are several reports of encephalitis after vaccination.

Design/Methods: We used that data from the Vaccine Adverse Event Reporting System (VAERS) which is a cooperative program for vaccine safety of the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA). VAERS is a post-marketing safety surveillance program, collecting information about adverse events (possible side effects) that occur after the administration of United States licensed vaccines.

Results: There were 1396 cases (mean age 23.44 years, range 0 to 89 years) of encephalitis reported after vaccination in the United States from 1990 to 2010. The onset of encephalitis within 6 weeks after vaccination was reported in 910 patients (65.2%) and in 708 patients (50.7%) within 2 weeks of vaccination. The date of vaccination in patients who developed encephalitis was unknown in 192 patients (13.7%). Hospitalization and disability were reported in 976 (69.9%) and 288 (20.6%) of patients, respectively. Encephalitis was reported in 354 cases (25.5%) after Hepatitis B vaccination, 208 cases (14.9%) who were vaccinated with the Flue vaccine, 208 cases (14.9%) who received Measles vaccine Mumps and Rubella (MMR) vaccine, and in 120 cases (8.6%) after Haemophilus influenza type B vaccination.

Conclusions: The Non-randomized distribution of encephalitis cases within 6 weeks after vaccination is suggestive that some cases are triggered by vaccines. More controlled studies and continuous monitoring are needed to assess the risk of encephalitis after vaccination.

Disclosure: Dr. Al Qudah has nothing to disclose. Dr. Abukwaik has nothing to disclose. Dr. Patel has nothing to disclose. Dr. Souayah has received personal compensation for activities with Walgreens as a consultant. Dr. Souayah has received research support from Talecris.