RESUMEN
In the Neapolitan area the prevalence of adult HBsAg carriers ranges from 4-7%. Moreover, hepatitis B virus (HBV) is responsible for most of the chronic hepatitis cases in childhood. Since the chronic carrier state in our area is acquired by early horizontal contact, we investigated the prevalence of HBV infection among 207 pre-school children and of HBsAg carriers among their family members. None of the children was found to be HBsAg positive and 3.9% of them had anti-HBs. HBsAg was positive in 29 out of 892 (3.3%) of the family members. There was a clear age-related distribution of the carriers, their prevalence reaching 6.7% among the elderly members. On the whole, 19 out of the 207 index cases had at least one HBsAg carrier in their family. The results suggest that in our area a decline of HBV endemia may be under way and that early intrafamily contact is no more a common pathway in acquiring an HBsAg carrier state.