Studies on Hepatitis B vaccination in neonates

Abstract

From 1982-1989, 705 infants born to HBsAg positive mothers entered the Dutch neonatal hepatitis B vaccination program and received passive-active hepatitis B immunization, according to 6 schedules, varying in time of onset vaccination, dose of hepatitis B immunoglobulin (HBlg) and type and dose of vaccine. 118 (17%) of the mothers were also HBeAg positive. This thesis describes the protective efficacy and long-term immunogenicity of passive-active hepatitis B immunization over a period of 10 years. During follow up, 9 infants became HBsAg carriers; 8, all born to HBeAg positive mothers within the first year and another child, born to an HBeAg negative mother at the age of 5 years. No evidence of emergence of escape hepatitis B mutants was found. Protective Efficacy Rate (PER) of passive-active hepatitis B immunization at 12 months follow up was 92% for the total group with no significant differences between groups starting active immunization at birth or at 3 months; groups receiving one or two doses of HBlg or groups receiving plasma-derived or recombinant vaccine. The PER at month 12 in the group with maternal HBV-DNA levels less than 150 pg/ml was 100% and significantly higher than the 68% for the group with HBV-DNA levels above 150 pg/ml. After 5 years of follow up, the group with active hepatitis B immunization starting at birth had significantly more infants with anti-HBs levels less than 10 IU/L (15%) than the corresponding group starting at 3 months (2%). Geometric Mean Titres of anti-HBs were significantly higher in the group, starting at 3 months of age with plasma vaccine than in the corresponding group receiving recombinant vaccine. This program showed that passive-active hepatitis B vaccination can be highly effective in the prevention of neonatal hepatitis B, except for children born to women with high hepatitis B viraemia. Evaluation of vaccine schedules should take into account risk assessment according to maternal HBV DNA levels. The excellent efficacy of delayed active vaccination allows incorporation of hepatitis B vaccine into the standard infant immunization programs for countries with a passive-active immunization strategy for hepatitis B. For long-term protection, dosage of recombinant vaccine with equal immunogenicity to that of plasma vaccine should be considered