Hepatitis B vaccine and multiple sclerosis
Hepatitis B vaccine has been used extensively in France in recent years, with more than 20 million persons being vaccinated. Several case reports have raised concerns that hepatitis B immunization may be linked to new cases or relapses of multiple sclerosis (MS). In response to public and professional concern, the French Ministry of Health on 1 October 1998 temporarily suspended the school-based adolescent hepatitis B vaccine programme. France maintained the recommendations for universal infant immunization and administration of the vaccine to adults at special risk, and reiterated their support for adolescent vaccination. This decision was misunderstood and interpreted as a ban on hepatitis B immunization, generating widespread concern in other countries.
Three possible theories explain the link between MS and hepatitis B vaccine: 1) coincidence, due to the large number of hepatitis B vaccine doses administered, many to individuals in the age groups in which MS first occurs; 2) “triggering”, an increased risk of demyelination following hepatitis B vaccine that would act as a “trigger” in individuals predisposed to develop MS or other central nervous system demyelinating disease; and 3) a true causal association between hepatitis B vaccination and MS or other demyelinating disease.
By 2001, more than 700 cases of central demyelinating diseases with a close match to the natural epidemiological distribution of MS had been reported to the French authorities, the majority in adult females. The time delay between the last dose of vaccine and the onset of neurological symptoms was from 1 day to 5 years (median: 60 days). No cases were reported among children < 25 months, despite vaccination of 1.8 million babies. Overall, 9 epidemiological studies have been carried out to estimate the risk (if any) of an association between vaccination with hepatitis B vaccine and a first attack or relapse of MS. None of the initial studies, despite a slightly elevated odds ratio, showed a statistically significantly increase in risk; the most recent studies do not indicate any excess risk. Analysis of data from spontaneous reports and epidemiological studies does not support a causal relationship between MS and hepatitis B vaccine. The most likely explanation is a coincidental association.
The conclusions of a recent report of the United States Institute of Medicine on an association between hepatitis B vaccine and demyelinating neurological disorders also did not support a causal relationship between hepatitis B vaccine administered to adults and MS or relapse of MS. GACVS has concluded that there is no reason to suggest a change in the recommendations for universal infant and adolescent immunization coverage with hepatitis B vaccine.