Combination vaccines can help protect against multiple diseases, provide a solution to the issue of a large number of injections during the first two years of life, and can also help simplify vaccination schedules. The United States Advisory Committee on Immunization Practices (ACIP) advocates the use of combination vaccines over lower-valent vaccines if they are licensed and indicated. It should be ensured that the combination vaccines are not less immunogenic, less effective, or more reactogenic than the lower-valent vaccines.

Hexavalent vaccines containing diphtheria, tetanus, pertussis, Haemophilus influenzae type b, poliomyelitis, and hepatitis B virus antigens can be put to use for the primary series in India (6, 10, 14 weeks of age) and the toddler booster dose. The hexavalent vaccines available in India include DTwP-Hib/HepB-IPV (wP-hexa), DTaP-IPV-HB-PRP~T(2aP-hexa), and DTaP-HBV-IPV/Hib (3aP-hexa). 

Phase-3 Indian studies have shown that 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 other five antigens were found to be 88.2-100%, 49.6-100%, and 98.6-100%, respectively. 

When used under the Indian schedule, hexavalent vaccines will be co-administered with rotavirus and/or pneumococcal conjugate vaccines (PCVs) at 6-10-14 weeks and with measles-mumps-rubella(MMR), varicella, measles-mumps-rubella-varicella (MMRV), and/or hepatitis A vaccines in the second year of life. While there is a lack of published data on wP-hexa co-administered with other vaccines, the product leaflet states that it can be given along with PCVs, MMR and rotavirus vaccines.

Studies conducted outside India have evaluated 2aP-hexa co-administration have reported no clinically significant interference on concomitant administration with PCV, MMR, rotavirus, or meningococcal conjugate vaccines.

Hexavalent vaccines appear to be a practical way to limit the number of injections required, simplify vaccination schedules, and enhance compliance.

Reference

1. Chitkara AJ, Parikh R, Mihalyi A, Kolhapure S. Hexavalent Vaccines in India: Current Status. Indian Pediatr 2019;56: 939-950