From the Guidelines
Vaccines that are live and parenteral, such as MMR and varicella, should not be administered within 28 days of each other, but can be given simultaneously or at least 4 weeks apart, as recommended by the Advisory Committee on Immunization Practices (ACIP) 1. When considering vaccine combinations, it's essential to prioritize the safety and efficacy of each vaccine.
- In general, inactivated vaccines can be administered concomitantly with other inactivated vaccines or live vaccines, without significant interference with immune responses 1.
- Live vaccines, on the other hand, may interfere with each other if administered too close together, and a minimum interval of 4 weeks is recommended between two live parenteral vaccines 1. Some specific vaccine combinations to consider:
- Pneumococcal vaccines PCV13 and PPSV23 should be separated by at least one year for optimal immune response, although this is not strictly a combination to avoid, but rather a timing consideration 1.
- COVID-19 vaccines can be administered with other vaccines, but the guidance may vary by country and evolve over time, and it is generally recommended to administer them on a separate day from other vaccines, if possible 1. It's crucial to consult current recommendations and guidelines for the most up-to-date information on vaccine combinations and timing, as these can change over time 1.
From the Research
Vaccines That Should Not Be Combined
The following vaccines have been identified as having potential interactions or interference when administered together:
- Yellow fever vaccine and measles-mumps-rubella (MMR) vaccine: studies have shown that simultaneous administration of these vaccines can result in lower seroconversion rates for rubella, yellow fever, and mumps 2
- Live measles and yellow fever vaccines and inactivated pentavalent vaccines: co-administration of these vaccines has been associated with increased mortality compared to receiving measles and yellow fever vaccines only 3
- MMR vaccine and yellow fever vaccine: interference in immune response has been observed when these vaccines are administered simultaneously 2
- Pentavalent vaccine and live vaccines (MV and YF): co-administration of these vaccines has been associated with increased mortality 3
Potential Interactions and Interference
Vaccine-vaccine interactions can occur due to various factors, including:
- Physical or chemical interactions within the vaccine formulation
- Interactions between live vaccines
- Immunological interference 4 These interactions can result in adverse reactions, loss of immunogenicity, or reduced protective efficacy 4
Importance of Vaccine Administration
It is essential to consider the potential interactions and interference between vaccines when administering multiple vaccines simultaneously or in close proximity 4, 2, 3 However, it is also important to note that combination vaccines can simplify immunization and reduce the burden on the immune system, and that licensed combination vaccines undergo extensive testing to ensure safety and efficacy 5