A randomized double-blind clinical trial of a mammalian cell-derived recombinant DNA hepatitis B vaccine compared with a plasma-derived vaccine.

Eight hundred volunteers from heath care and emergency fields participated in a randomized double-blind clinical trial of a new experimental mammalian cell-derived recombinant DNA hepatitis B vaccine (Betagen) compared with a licensed plasma-derived vaccine (Heptavax-B). Vaccine injections (20 micrograms) were administered intramuscularly at 0, 1, and 6 months, and sera were tested at 0, 1, 2, 3, 6, 7, and 12 months for hepatitis B surface antigen, antibody to hepatitis B surface antigen, and antibody to hepatitis B core antigen. Data from 745 vaccinees (93.1%), analyzed at the 7th month of follow-up, showed no significant difference in the seroconversion rates for Betagen (94.4%) vs Heptavax-B (97.3%), but the geometric mean titer of antibody was significantly higher for Heptavax-B (11 833 mIU/L) than for Betagen (4628 mIU/mL). The antibody response of Betagen was significantly and independently related to age and sex, while that of Heptavax-B was related to age only. Reported side effects from both vaccines were minor and mild, with approximately one fourth of all vaccinees reporting at least one side effect. Vaccinees, who had a protective level of antibody at the 7th month, were tested for antibodies at the 12th month. Of those in the Betagen-vaccinated group and those in the Heptavax-B-vaccinated group, 99.0% and 100%, respectively, were still protected. There was a proportionately larger decline in the geometric mean titers of antibody to hepatitis B surface antigen for Heptavax-B than for Betagen.

Prevalence of hepatitis B markers in occupational health nurses.

A seroprevalence study was undertaken at the 14th Annual Conference of the Occupational Health Nurses Association of Ontario. A total of 151 self-selected registrants (33%) provided demographic, health, and occupational information. Blood was drawn for hepatitis B serology (hepatitis B surface antigen, core antibody, and surface antibody). Vaccine-induced seropositivity was found in 11 persons (7.3%) while naturally occurring markers were present in 13 nurses (8.6%). This exceeds the natural prevalence of markers in Canada (4% to 6%) but is less than that seen in emergency and renal dialysis nurses. It implies that occupational health nurses are at less risk for hepatitis B virus infection than their acute care hospital colleagues.