One thousand three hundred and twenty adults at risk of occupational exposure to hepatitis B were immunized using genetically engineered surface antigen and their antibody response (anti-HBs IU/1) assessed. Sex was known for all subjects and age for 1120 (range from 17–71 years). Seven hundred and sixty-four subjects were immunized in the local Department of Occupational Health, the remainder mainly by general practitioners.
Analysis of ‘good responders’ (anti-HBs > 100 IU/1) according to age and sex showed that increasing age and male sex had independent adverse effects on the likelihood of developing a satisfactory level of antibody to HBsAg. Furthermore even those most likely to respond well (young women), had a 1/5 to 1/6 failure rate to achieve > 100 IU/1 anti-HBs.
Of 63 persons who received a fourth dose of vaccine, 26 developed anti-HBs titres > 100 IU/1 when tested after 6 months. Subjects who had a low level of anti-HBs following primary immunization were more likely to develop > 100 IU/1 anti-HBs following a booster dose than were non-responders (< 10 IU/1).