Abstract
Four thousand and one hospital staff were screened for hepatitis B virus (HBV) markers in a vaccination programme in Hong Kong. The seropositivity rate for HBsAg, anti-HBs and anti-HBc were significantly higher in the 3160 existing hospital staff than in 841 new recruits. Of the subjects negative for HBV markers, 605 were randomized to receive three doses of either 10 or 20 micrograms of the Merck Institute vaccine (HB-VAX). Compared with the 20 micrograms dose, vaccination with the 10 micrograms dose results in equal immunogenicity and efficacy at the completion of the three injections but induced a slower response rate and lower anti-HBs titres with the first two doses. The commonest side-effect of local soreness was less with the 10 micrograms dose. We conclude that (1) hospital staff working in high endemic areas should be vaccinated on recruitment and (2) the 10 micrograms dose of HB-VAX can replace the recommended 20 micrograms dose for adults, being cheaper and as efficacious.