[HEPATITIS B.VACCINATION IMPACT ON ACUTE DISEASE,CHRONIC CARRIERS AND HEPATOCARCINOMA INCIDENCE]

BACKGROUND: Hepatitis B virus is the cause of acute disease and several chronic conditions, such as chronic hepatitis, cirrhosis and liver cancer.In 1982, hepatitis B vaccine was developed. Since 1984, many immunization programs against hepatitis B were implemented in several countries and 15 years later we can visualize some epidemiological changes in those countries.OBJECTIVE: To review the papers published about the results of hepatitis B immunization programs in several countries from Asia, Africa, Europe (Italy) and Peru, since 1984.METHODS: Pertinent literature was identified in MEDLINE (1980-2000) and references quoted in published papers. RESULTS: The impact of vaccination against hepatitis B over the incidence of acute disease, chronic carriers, hepatitis B virus prevalence and hepatocarcinoma incidence, was anayzed.The following results were obtained: In Afragola (Italy), a reduction of acute disease incidence from 63 cases/100,000 population before the vaccination (1983), to 3 cases/100,000 population after the vaccination (1997), was obtained HBsAg carriers rate decreased: From 13.4% to 3.7% in the general population and from 6.8% to 0.7% in infant population.Infection prevalence: From 66.9% to 34.2% in general population. In Taiwan:HBsAg carriers rate decreased: From 10.0% to <1.0% in children from 1 to 10 years old.Infection prevalence: From 38.0% to 16.0% in children under 13 years old. In Peru:Infection prevalence: From 24.4-30.4% to 2.3-5.1% in children of 3 and 4 years old. In Senegal:HBsAg carriers rate decreased: From 18.7% to 2.2% in children. In Gambia:HBsAg carriers rate decreased: From 10.0% to 0.6% in children.Finally, the hepatocarcinoma incidence in children from 6 to 14 years old, decreased from 0.70/100,000 children to 0.36/100,000 (p<0.01) in Taiwan.CONCLUSION: The results of these studies support the hypothesis that the vaccination against the hepatitis B virus infection reduce the incidence of acute disease, carriers rate, prevalence of the infection and hepatocarcinoma incidence.