Large-scale epidemics of non-B (HBsAg-negative) hepatitis have occurred in the Israel Defense Forces prior to post- and preexposure immune serum globulin administration. Presently, hepatitis morbidity rates have stabilized around 1 to 2 per 1,000. Several years after vaccine initiation, a comparison of epidemiological features was made in order to redefine risk groups. Seasonal morbidity, sex, ethnic origin and educational status (as a representative of socioeconomic level) were not different after the preexposure immunization compared to the preimmunization era. Therefore, a more selective immunization is proposed.