In a comparison of the pentavalent or the hexavalent hepatitis B (HB) vaccine, both were found to be effective in inducting anti-HB levels ≥10 mIU/mL and can be used as a single formula booster at age 18 months. These results come from data published in the journal Vaccine from a study investigating the immunogenicity profiles of children in Thailand.

Investigators recruited infants in Thailand whose mothers had previously received the tetanus-diphtheria-acellular pertussis vaccine (Tdap) and randomly vaccinated them with either pentavalent or hexavalent vaccine at 2, 4, 6, and 18 months after receiving monovalent HB vaccine at birth.

After 4-dose immunization at 0, 2, 4, and 6 months in both the hexavalent and pentavalent groups, 99.2% of patients achieved anti-HB levels ≥10 mIU/mL. Of the group of infants in the Extended Program on Immunization (EPI) — an HB vaccination program for newborns in 2 Thai provinces that has been in place since 1988 — 98% of the pentavalent group achieved these levels. The researchers also recruited a convenience sample of 80 full-term infants born to non-Tdap-vaccinated women and designated this group the EPI pentavalent group. This sample received the pentavalent wP-containing vaccine (Quinvaxem) according to the current Thai EPI.

A month after the additional dose at age 18 months, researchers observed anti-HB levels ≥10 mIU/ml in 100%, 99.2%, and 93.8% of infants in the hexavalent, pentavalent, and EPI pentavalent groups, respectively. They observed a higher percentage of infants achieving these anti-HB levels in the hexavalent group (98.3%) compared with the pentavalent group (86.5%) at 24 months of age.

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According to the researchers, this study demonstrated the efficacy of 2 types of combined vaccines at eliciting adequate anti-HB levels. Both can therefore be distributed as a single formula booster to infants at age 18 months to simplify vaccine administration under the EPI.

Reference

Posuwan N, Wanlapakorn N, Vongpunsawad S, et al. Comparison of hepatitis B surface antibody levels induced by the pentavalent DTwP-HB-Hib versus the hexavalent DTaP-HB-Hib-IPV vaccine, administered to infants at 2, 4, 6, and 18 months of age, following monovalent hepatitis B vaccination at birth [published online January 14 2020]. Vaccine. doi:10.1016/j.vaccine.2019.12.065