Hepatitis B vaccination and the risk of multiple sclerosis

Background: Reports of multiple sclerosis developing after hepatitis B vacc ination have led to the concern that this vaccine might be a cause of multi ple sclerosis in previously healthy subjects. Methods: We conducted a nested case-control study in two large cohorts of n urses in the United States, those in the Nurses' Health Study (which has fo llowed 121,700 women since 1976) and those in the Nurses' Health Study II ( which has followed 116,671 women since 1989). For each woman with multiple sclerosis, we selected as controls five healthy women and one woman with br east cancer. Information about hepatitis B vaccination was obtained by mean s of a mailed questionnaire and was confirmed by means of vaccination certi ficates. The analyses included 192 women with multiple sclerosis and 645 ma tched controls (534 healthy controls and 111 with breast cancer) and were c onducted with the use of conditional logistic regression. Results: The multivariate relative risk of multiple sclerosis associated wi th exposure to the hepatitis B vaccine at any time before the onset of the disease was 0.9 (95 percent confidence interval, 0.5 to 1.6). The relative risk associated with hepatitis B vaccination within two years before the on set of the disease was 0.7 (95 percent confidence interval, 0.3 to 1.8). Th e results were similar in analyses restricted to women with multiple sclero sis that began after the introduction of the recombinant hepatitis B vaccin e. There was also no association between the number of doses of vaccine rec eived and the risk of multiple sclerosis. Conclusions: These results indicate no association between hepatitis B vacc ination and the development of multiple sclerosis. (N Engl J Med 2001;344:3 27-32.) Copyright (C) 2001 Massachusetts Medical Society.