One year evaluation of immunogenicity conferred by a Chinese hamster ovary cell recombinant hepatitis B vaccine in a French Polynesian newborn immunization programme.

In 1988, a hepatitis immunization programme, using a Chinese hamster ovary (CHO) cell recombinant vaccine, was implemented for newborn children in the Austral archipelago (French Polynesia). Three different schedules were used: (i) 4 vaccine doses at months (M) 0, M1, M2 and M12; (ii) 3 vaccine doses at M0, M1, M6; and (iii) 3 vaccine doses at M0, M1, M2. Results at the one year follow-up may be summarized as follows. Of 197 infants who received one or more doses of CHO-recombinant vaccine, (i) none was an HBsAg carrier; (ii) 89.5% had anti-HBs-antibody titres > 10 miu/ml; and (iii) 95.9% had seroconverted for at least one of the 2 antibodies studied (anti-HBs or anti-pre-S2). After 2 doses (M0, M1), anti-HBs seroconversion rate and geometric mean titre were, respectively, 82.6% and 98.47 miu/ml. After 3 doses, seroconversion rates and geometric mean titres were, respectively, 91.1% and 200.59 miu/ml using schedule M0, M1, M2, and 100% and 1253.4 miu/ml using the M0, M1, M6 schedule. None of the 7 vaccinated neonates born to HBsAg/HBeAg positive mothers was found to be an HBsAg carrier. These preliminary results indicate that, in field conditions, vaccination with a CHO-recombinant vaccine resulted in high immunogenicity.