Age-specific prevalence of hepatitis B virus infection among children in an endemic area in southern Italy.

In 1989 the prevalence of hepatitis B virus markers was studied by radioimmunoassay in a sample of 1,426 healthy children, 3 to 11 years old, attending kindergarten and the primary schools in a large urban area of the Apulia Region in Southern Italy, where the hepatitis B surface antigen (HBsAg) prevalence among pregnant women is 5.6%. The overall prevalence of any hepatitis B virus marker was 3.4%, increasing from 1.7% in 3- to 5-year-old children to 5% in 10- to 11-year-old children (P less than 0.002). Prevalence was not associated with the father's years of schooling (odds ratio, 1.98; confidence interval, 95% (0.9 to 4.6] or with the family size (odds ratio, 2.96; confidence interval, (0.7 to 11.8]. The overall HBsAg prevalence was 0.8, a rate that was lower than the 5.6% found in pregnant women. The finding of only 12 HBsAg-positive children of the 1,426 tested, despite 80 of them being born to HBsAg-positive carrier mothers (on the basis of the 5.6% HBsAg prevalence among pregnant women), is probably attributable to the low proportion (5%) of hepatitis B e antigen positivity among the HBsAg-positive carrier mothers in the study area. The observed low HBV infection rate in younger age groups, which confirms recent studies in other areas of Italy, appears to be the result of several factors: improved socioeconomic conditions; decreased family size; and increased use of disposable syringes in the last few years.