Limited family clustering of hepatitis B surface antigen in a Melanesian population.

The entire population of Graciosa Bay, Santa Cruz, Solomon Islands, was tested for hepatitis B surface antigen (HBsAg) by reverse passive hemagglutination and antibody to HBsAg (anti-HBs) by passive hemagglutination. Analysis of the distribution of HBsAg in relatives of HBsAg carriers and non-carriers showed clustering only in children of carrier mothers. Similarly, there was no clustering of total exposure as measured by serologic tests except in children of carrier parents primarily due to the antibody and antigen of children of carrier mothers. This distribution pattern is probably due to cultural and environmental factors which increase exposure between HBsAg carriers and people who are not related to them and also reduce the amount of contact between siblings.