Most cases in the United States are transmitted by close personal contact during community outbreaks and sometimes by eating food or drinking water contaminated with the virus. The virus is shed in the stool of those infected with hepatitis A. A person who has hepatitis A can easily pass the disease to others within the same household. The lowest rates are seen among Asian populations. Communities at high risk are relatively well defined, either geographically or culturally, and include American Indian, Alaskan Native, and selected Hispanic, migrant, and religious communities. The hepatitis A vaccine was made available in the United States in 1995 and consists of two immunizations administered 6-12 months apart.
Immunity is believed to be life-long.
All young adults not previously immunized. Hepatitis B is a virus with a wide range of acute and chronic consequences. Immunization with hepatitis B vaccine is the most effective means of preventing hepatitis B infection and its consequences. In the United States, most hepatitis B infections occur among adults and adolescents. Prevention has been directed at the selective vaccination of persons with identified risk factors.