Q: What do we know about “mixing and matching” vaccine doses of different types?
A: In the U.S., CDC currently recommends receiving vaccines from the same manufacturer for the primary series and any subsequent boosters or updated vaccines, whenever possible.
FDA has authorized the use of heterologous (or “mix and match”) vaccine doses received after the primary series, as long as they are currently FDA-authorized or approved COVID-19 vaccines. CDC guidance addresses clinical considerations related to heterologous booster doses, including patient benefit-risk considerations when selecting which booster dose to receive.
Existing evidence from the U.K., the U.S. and Brazil suggests that heterologous dosing does not pose additional safety concerns and is effective (Munro, December 2021; Atmar, March 2022; Costa Clemens, February 2022), including during the Omicron phase (Seidel, July 2022).