Anti-HBs Titers Following Pentavalent Immunization (DTwP-HBV-Hib) in Term Normal Weight vs Low Birthweight Infants.

Objective: To compare anti-HBs titers between term low birth weight (1800-2499 g) infants and normal birthweight infants, 6 weeks after last dose of primary immunization with pentavalent vaccine, and to study adverse events following immunization (AEFI) with pentavalent vaccine.

Design: Cohort study.

Setting: Tertiary-care hospital predominantly catering to urban poor population of East Delhi.

Participants: 265 low birthweight (1800-2499 g) and 265 normal birthweight (2500-4000 g) infants. Monovalent Hepatitis B vaccine was administered within 24 hours of birth followed by three primary doses of pentavalent vaccine at 6, 10 and 14 weeks. Anti-HBs titers were estimated after 6 weeks of third dose of pentavalent vaccine. Adverse events following immunization (AEFI) month were observed for a month after each dose of pentavalent vaccine.

Main Outcome Measures: Anti HBs antibody titers after 6 weeks of primary immunization, and AEFI.

Results: 443 (83.5%) infants (225 low birthweight and 218 normal birthweight infants) completed the follow-up. Seroprotection against hepatitis B virus was achieved in both groups after pentavalent vaccine administration. Anti HBs GMTs in low birthweight infants (194.8 mIU/mL) and normal birthweight infants (204.2 mIU/mL) were comparable (P = 0.17). No serious adverse events were observed in either group.

Conclusions: Three primary doses of pentavalent vaccine administered along with zero dose of Hepatitis B vaccine at birth provide good seroprotection. The vaccine appears to be safe in both low birth weight and normal birthweight infants born at term.