A pilot model of vaccination against hepatitis B virus suitable for mass vaccination campaigns in hyperendemic areas.

A hepatitis B vaccination campaign was carried out in a town of 60,000 inhabitants, Afragola, Campania, Italy, a hyperendemic area for hepatitis B where HBsAg prevalence was 13.4% and anti-HBc prevalence was 64.7%. This experimental pilot project aimed to reduce the incidence of both acute and asymptomatic viral hepatitis B and of related chronic liver complications. From 1983-1989, 8,400 subjects were vaccinated: 6,900 children up to 10 years of age and 1,500 subjects from 11-60 years of age. High seroconversion rates were observed: 99.0% in all children under one year of age, 96.0% in the older children, and 86.7% in adults. The rate of infection in Afragola has diminished from 63/100,000 in 1983 to 10/100,000 in 1989. Carriers of HBsAg decreased in the general population (7.3% compared to 13.4%), especially in children up to 10 years of age (1.0% compared to 9.0%). In babies who received hepatitis B vaccine at the same time as compulsory vaccinations compliance was 98% while it was 80% in babies who were vaccinated separately. In June 1991 the Italian Parliament promulgated a decree which imposes hepatitis B vaccination for all newborn babies at 3, 5, and 11 months of age, at the same times as the mandatory childhood vaccinations (diphtheria, tetanus, and polio) according to a new protocol (Piazza scheme) which has been in use since January 1987 in our pilot vaccination campaign in Afragola.