Hepatitis B infection in infants after neonatal immunization

A double-blind randomized placebo-controlled study to prevent hepatitis B infection in 235 babies born to chronic hepatitis B, HBeAg carriers was carried out. Babies in three treatment groups all received heat-inactivated hepatitis B vaccine. In addition multiple doses of HBIG and a single dose of HBIG were given in groups I and II respectively. After three years of follow-up, 4/60 (Group I), 3/64 (Group II), and 1/64 (Group III) developed chronic infection. For those who escaped chronic infection, other hepatitis events also occurred. They were transient HBs-antigenaemia, anti-HBc conversion and significant rise in anti-HBs titre without seroconversion for anti-HBc. It was deduced that 30% of babies born to hepatitis carriers are naturally protected from chronic infection. Immunization, with vaccine only, protects another 46%. The addition of single and multiple doses of HBIG protects another 10% and 5%, respectively. 2% acquired intrauterine infection and 7% failed to respond to the most intensive immunization schedule