Interchangeability of Hexaxim and Infanrix Hexa
Hexaxim and Infanrix Hexa can be used interchangeably in vaccination schedules when necessary, as any licensed DTaP vaccines may be used to complete the vaccination series when the previously administered vaccine is unavailable or unknown. 1, 2
Vaccine Composition and Similarities
Both Hexaxim and Infanrix Hexa are hexavalent vaccines containing:
- Diphtheria toxoid
- Tetanus toxoid
- Acellular pertussis components
- Hepatitis B surface antigen
- Inactivated poliovirus (types 1,2, and 3)
- Haemophilus influenzae type b conjugate
Guidelines on Interchangeability
- The Advisory Committee on Immunization Practices (ACIP) recommends that whenever feasible, the same manufacturer's DTaP vaccine should be used for all doses of the vaccination series 1
- However, vaccination should not be deferred because the specific DTaP vaccine previously administered is unavailable or unknown 1
- Any of the licensed DTaP vaccines may be used to complete the vaccination series when necessary 1, 2
- Limited data exist regarding the safety, immunogenicity, and efficacy of using DTaP vaccines from different manufacturers for successive doses 1
Evidence Supporting Interchangeability
- Studies have shown that infants who receive sequential doses of different vaccines produce satisfactory antibody responses after completing the primary series 2, 3
- When at least one dose of a vaccine produced by one manufacturer is followed by subsequent doses from a different manufacturer, the immune response has been comparable with that resulting from a full course of vaccination with a single vaccine 2
- Research specifically examining Infanrix Hexa as a booster following primary vaccination with either Infanrix Hexa or another hexavalent vaccine (Hexavac) showed strong immune responses to all antigens regardless of the primary vaccine used 3
- Post-booster seroprotection rates were comparable between different primary vaccine groups (ranging from 98.1% to 100%) 3
Clinical Considerations When Switching Vaccines
- When switching between vaccine brands, ensure that all required antigens for the child's age and vaccination schedule are provided 4
- An interruption in the vaccination schedule does not require restarting the entire series 2
- Longer-than-recommended intervals between vaccine doses do not reduce final antibody concentrations 2
- For Haemophilus influenzae type b (Hib) vaccines, if different brands of Hib conjugate vaccine are administered, a total of three doses is considered adequate for the primary series among infants 2
Common Pitfalls and Caveats
- Delaying vaccination because the brand used for previous doses is not available or is unknown should be avoided 2, 4
- Self-reported doses of vaccine without written documentation should not be accepted 2
- When using combination vaccines from different manufacturers, be aware that there may be slight differences in antigen content and formulation that could theoretically affect immunogenicity 5
- Some studies have shown differences in prebooster persistence of antibodies between different hexavalent vaccines, particularly for hepatitis B, Hib, and poliovirus components 3
- Concurrent administration of certain vaccines (like IPV) with combination vaccines may affect immune responses to some components, so follow recommended schedules 6
In conclusion, while using the same manufacturer's product throughout the vaccination series is preferable, the benefits of completing vaccination on schedule outweigh any theoretical concerns about mixing vaccine brands. Both Hexaxim and Infanrix Hexa can be used interchangeably when necessary to ensure timely and complete immunization.