If a 2-year-old patient has inadvertently received different brands of mRNA COVID-19 vaccines as the first two doses of his primary series, what should the child receive now?

In this specific situation, CDC states that a child age 6 months–4 years who received 1 Moderna and 1 Pfizer-BioNTech COVID-19 vaccine dose for the first 2 doses of COVID-19 vaccine should receive a third dose of the 2024–2025 Formula of either Moderna or Pfizer-BioNTech COVID-19 vaccine at least 8 weeks after the second dose.

For all questions of brand interchangeability, please review CDC’s interim recommendations: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#Interchangeability.