Implementation Guidance

Simultaneous administration of COVID-19 vaccines with other vaccines

Routine administration of all age-appropriate doses of vaccines simultaneously, also known as coadministration, is acceptable for children, adolescents, and adults if there are no contraindications at the time of the healthcare visit.

There are additional considerations for simultaneous administration of an orthopoxvirus vaccine and COVID-19 vaccine as follows:

• There is no required minimum interval between receiving a dose of any COVID-19 vaccine and an orthopoxvirus vaccine, either JYNNEOS or ACAM2000 vaccine (e.g., for monkeypox prevention), regardless of which vaccine is administered first.

• Use of JYNNEOS vaccine should be prioritized over ACAM2000 in most scenarios when co-administering a COVID-19 vaccine and an orthopoxvirus vaccine.

• People, particularly adolescent or young adult males, who are recommended to receive both vaccines might consider waiting 4 weeks between vaccines out of an abundance of caution. This is because of the observed risk for myocarditis and pericarditis after receipt of ACAM2000 orthopoxvirus vaccine and COVID-19 vaccines, and the hypothetical risk for myocarditis and pericarditis after JYNNEOS vaccine. However, if a patient's risk for monkeypox or severe disease due to COVID-19 is increased, administration of monkeypox and COVID-19 vaccines should not be delayed.
  
• As with all medical decision making between patients and their healthcare providers, patients should discuss the benefits and risks of simultaneous receipt of a COVID-19 vaccine and an orthopoxvirus vaccine to make informed and personalized decisions about vaccination.

Nirsevimab and Clesrovimab: Simultaneous administration of COVID-19 vaccine and nirsevimab or clesrovimab (long-acting monoclonal antibodies indicated for certain infants and young children for prevention of respiratory syncytial virus [RSV] lower respiratory tract disease) is acceptable.

Interchangeability of COVID-19 vaccines

Where multiple doses are administered off-label, the same COVID-19 vaccine should be administered whenever recommended (Table 1 and Table 2). In the following circumstances, a different age-appropriate COVID-19 vaccine may be administered:

• Same vaccine not available at the time of the clinic visit

• Previous dose unknown

• Person would otherwise not receive a recommended vaccine dose

• Person starts but unable to complete a vaccination series with the same COVID-19 vaccine due to a contraindication

Because there is no current FDA-approved or FDA-authorized Pfizer-BioNTech COVID-19 Vaccine for children ages 6 months–4 years, the 2026-2027 COVID-19 vaccination schedule has been modified to ensure children previously vaccinated with Pfizer-BioNTech COVID-19 Vaccine receive a 2026-2027 COVID-19 vaccine dose(s) with Moderna (Spikevax) COVID-19 Vaccine (Table 1 and Table 2).