ABSTRACT
Viral hepatitis is the most common cause of liver disease in the world. In the past 30 years, highly effective vaccines have become available for two of the five hepatitis viruses, and where implemented, vaccination has become a key component of hepatitis prevention. To provide a current review and critical analysis of the viral hepatitis, A [HAV] and B [HBV] prevention by immunization has been presented in this article.Review of medical articles obtained from Medline 2000 to 2007 and Iran Medix [1377 to 1386] database. There are signitificant differences regarding epidemiology of hepatitis A and B viruses' infection between countries. A zero prevalence rate was highly correlated with sanitation and socio-economic conditions. Dramatic vaccine-induced declines in the incidence of both hepatitis A and B and have occurred in countries where HAV and HBV vaccines were integrated into universal childhood immunization. Improved sanitation and living conditions leads to a decline in the average HAV zero prevalence rates. Planning for large-scale immunization programs against HAV should involve careful analysis of the cost-benefit and sustainability in different appropriate hepatitis A prevention strategies. Due to the grave impact of universal infant HB vaccination on prevalence of HBV infections, continued universal infant HB vaccination is recommended. Moreover, this is to ensure continued success of hepatitis B immunization. The need for booster doses to preserve vaccine-induced immunity should be evaluated regularly as vaccinated cohort age