[Control of hepatitis B in French Polynesia with a program of systematic vaccination of newborns with the Genhevac B vaccine].

In 1988, a 5-year vaccination program against hepatitis B was launched for all newborns in a pilot area, the Austral archipelago in French Polynesia. Genhevac B, a recombinant vaccine produced from mammalian cells was administered. Three different immunization schedules were used, none of them including additional specific immunoglobulin: i) four doses, one at each months (M) 0, 1, 2, and 12; ii) three doses one at each MO, M1 and M6; and iii) three doses one at each MO, M1 and M12. Each year during the 5 year period a serological survey was conducted. Of the 837 children who received at least one vaccine dose, 5 were HBsAg carriers. Seroprotection rates for anti-HBs and anti-PreS2 antibodies were 88% after one dose and 97% after two doses. After the third dose, seroprotection rates and geometric mean titers of anti-HBs antibodies were 95% and 217 mIU/ml for schedule (i) (three dose only); 92% and 389 mIU/ml for schedule (ii) and 93% and 344 mIU/ml for schedule (iii) respectively. After four doses (schedule i) the values were 100% and 1228 mIU/ml. Of the 18 newborns whose mothers were positive for both HBsAg and HBeAg, one was a HBsAg carrier. The estimated protective rate for prevention of perinatal transmission was 94%. This study suggests that in field conditions, systematic vaccination of newborns without using specific immunoglobulins can confer early protection. The schedule recommended for use in French Polynesia was three doses, at MO, M1 and M6-12 (between 6 and 12 months) with an additional booster dose at age 6 years, the last year of nursery school. Since April 1992, all children born in French Polynesia have been vaccinated according to this schedule. A catch-up program has been implemented for children aged 4 to 10 years old using a similar immunization schedule.