[Risk-benefit assessment of hepatitis B vaccination in France, 2006]

Rare and unexpected adverse events following hepatitis B immunization have been reported. This article aims to illustrate the risk-benefit assessment of hepatitis B immunization strategies, using the available evidence in medical literature.

i) Hepatitis B vaccination efficacy is high in infants, children and adolescents. It may be lower in adults and at risk populations; ii) Hepatitis B descriptive epidemiological data in France are scarce, fragmental, unprecise and changing according to the studied population strata. The incidence of symptomatic cases in the general population is below 5 per 100,000 since the year 2000. In France, it is estimated that about 300,000 adults are carriers of HBs antigen, and thus able to transmit the disease; iii) The actual French pharmacovigilance signal and the epidemiological studies may suggest the hypothesis of an association between the occurrence of central nervous system demyelinating diseases and hepatitis B vaccination. If this association exists, the relative risk is probably of less than 3.

The lack of accuracy of risks estimates complicates the risk-benefit assessment of hepatitis B vaccination. Its perception is then influenced and distorted by subjective factors, underlying the need for research in communication about benefits and risks of immunizations. Although still debated, the hypothesis of a putative role of hepatitis B vaccine in the pathophysiology of demyelinating diseases should prompt to pursue experimental and epidemiological research to better understand the links between infectious environment and inflammatory chronic diseases.