Hepatitis A Vaccine

Hepatitis A continues to cause sporadic cases, epidemics, and occasional deaths in the United States. A killed virus vaccine for immunization against hepatitis A has recently been approved by the Food and Drug Administration. One hundred percent seroconversion occurs after a series consisting of a primary dose and a second booster shot 6–12 months later. Co-administration of immune-globulin and hepatitis A vaccine lowers ultimate antibody levels 50% compared with vaccine alone. Targets for immunization will probably be children, international travelers, military personnel, and food handlers. It will also be useful for general vaccination in areas where smoldering epidemics occur. Natural immunity levels in the United States population have undergone a significant decline since 1980 and are currently in the 21–33% range. Prescreening for immunity is likely to be cost-effective in persons over age 40.