Hexavalent Vaccines in India: Current Status.

Hexavalent vaccines containing diphtheria, tetanus, pertussis, Haemophilus influenzae type b, poliomyelitis, and hepatitis B virus antigens have the potential to be used for the primary series in India (6, 10, 14 weeks of age) and the toddler booster dose. 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). In the three published phase-3 Indian studies, pertussis 'vaccine response' rates 1 month after a 6-10-14-week primary series were 68.4-75.7% for wP-hexa, 93.8-99.3% for 2aP-hexa, and 97.0-100% for 3aP-hexa; seroprotection rates for the other five antigens were 88.2-100%, 49.6-100%, and 98.6-100%, respectively. Studies outside India show: good immunogenicity/safety after boosting dosing; immune persistence to age 4.5 years (2aP-hexa), 7-9 years (3aP-hexa) (all antigens), and 9-10 and 14-15 years, respectively (hepatitis B); and successful co-administration with other vaccines. Hexavalent vaccines could reduce the number of injections, simplify vaccination schedules, and improve compliance.