Hepatitis B Vaccination and First Central Nervous System Demyelinating Event: A Case-Control Study

Abstract

Objective: To investigate the relationship between hepatitis B (HB) vaccination and a first central nervous system (CNS) demyelinating event in adults. Methods: In 1998, we conducted a multicentre, hospital-based case-control study which enrolled 402 cases of first CNS demyelinating event occurring between 1994 and 1995 and 722 controls matched for centre, age, sex and date of admission. An independent expert committee validated the diagnoses of cases and controls. Data on vaccinations were obtained from a standardized phone interview. Forty percent of eligible cases and 50% of eligible controls could not be localized or were excluded because they did not satisfy inclusion or matching criteria. Results: Conditional logistic regression performed on 236 and 355 matched controls showed that adjusted odds ratios for the first CNS demyelinating event within 2 months following an injection of HB vaccine were 1.8 [95% confidence interval (CI), 0.7–4.6] in the whole group and 1.4 (95% CI, 0.4–4.5) in the subgroup of cases (n = 152) and controls (n = 253) referring to vaccination certificates during the phone interview. Restricting the analyses to the cases with definite or probable multiple sclerosis, these odds ratios were 2.0 (95% CI, 0.8–5.4) and 1.6 (95% CI, 0.4–5.6), respectively. Odds ratios tend towards 1 for a longer interval between HB vaccine and demyelinating event. Conclusions: This study was sufficiently powerful to rule out a strong association between HB vaccine exposure and a subsequent demyelinating event. However, it could not provide a clear indication of a moderately increased risk of a CNS demyelinating event shortly after HB vaccination in adults.