Hexavalent Vaccines in India: Current Status

Area of Science:

• Immunology
• Vaccinology
• Pediatrics

Background:

• Hexavalent vaccines combine diphtheria, tetanus, pertussis, Haemophilus influenzae type b, poliomyelitis, and hepatitis B antigens.
• Three hexavalent vaccines are available in India: DTwP-Hib/HepB-IPV (wP-hexa), DTaP-IPV-HB-PRP~T(2aP-hexa), and DTaP-HBV-IPV/Hib (3aP-hexa).

Purpose of the Study:

• To evaluate the immunogenicity and safety of hexavalent vaccines for primary immunization series and booster doses in India.
• To compare the efficacy of different hexavalent vaccine formulations.

Main Methods:

• Phase-3 Indian studies assessed pertussis vaccine response rates and seroprotection for other antigens after a 6-10-14 week primary series.
• External studies evaluated booster dosing, immune persistence, and co-administration with other vaccines.

Main Results:

• Acellular pertussis-based hexavalent vaccines (2aP-hexa, 3aP-hexa) showed significantly higher pertussis response rates (93.8-100%) compared to whole-cell pertussis-based (wP-hexa) vaccine (68.4-75.7%).
• Seroprotection rates for other antigens ranged from 49.6% to 100% across different vaccines.
• Studies indicated good immunogenicity and safety for booster doses, with sustained immune responses for up to 15 years for certain antigens.

Conclusions:

• Hexavalent vaccines, particularly acellular pertussis formulations, are effective for primary immunization in India.
• These vaccines simplify vaccination schedules, potentially improving compliance and reducing the number of injections.
• Further research supports their use for booster doses and co-administration with other pediatric vaccines.