Epidemiological features of hepatitis B virus infection in Malaysians.

In order to plan a strategy for control of hepatitis B virus infection in Malaysia, we determined (i) the annual rate of infection, (ii) the basic reproductive rate, Ro, of this infection, and (iii) the cost-effectiveness of HBeAg screening versus HBsAg screening of pregnant females to allow identification of neonates at risk of vertically transmitted infection. HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc markers were tested by radioimmunoassay in sera from 1435 Malaysian subjects aged 3 months to 67 years. The mean age of infection calculated by life table analysis was 15 years (Ro = 6). The rate of infection was highest during the first 10 years of life, when infection occurred in 2% of children per year. An increased infection rate occured in males, after the age of 14 years. By the age of 50 years, 62% of males and 50% of females had been exposed to HBV. On the premise that vertical transmission, of HBV occurs from HBeAg positive mothers, then HBeAg screening would have been more cost-effective than HBsAg screening. We conclude that all Malaysian children are at high risk of infection and that the aim must be towards mass neonatal vaccination.