Ask the Experts: All Questions

Ask the Experts is one of our most popular destinations for healthcare professionals. Our experts provide clear, easy-to-understand answers to commonly asked questions about vaccines and their use.

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An excellent resource for vaccine contraindications and precautions is the CDC online resource, “General Best Practice Guidelines for Immunization”. A table in the Contraindications and Precautions chapter has a listing for all routine vaccines in the United States available at www.cdc.gov/vaccines/hcp/acip-recs/general-recs/contraindications.html. In addition, a table of contraindications and precautions is provided in the appendix of current CDC recommended adult and child/adolescent immunization schedules, available at www.cdc.gov/vaccines/schedules/hcp/index.html.

Last reviewed: February 19, 2024

With the exception of two vaccines used to prevent smallpox or mpox (previously known as monkeypox), there is no recommendation to wait until a vaccine reaches room temperature before administration. The vaccine should be administered as soon as it is prepared.

The live smallpox (vaccinia) vaccine, ACAM2000 (Emergent Product Development Gaithersburg, Inc.) and the non-replicating, live smallpox and mpox vaccine, Jynneos (Bavarian Nordic) should be brought to room temperature before use, according to the package inserts for these two products.

Last reviewed: December 28, 2022

CDC has included in the Vaccine Storage and Handling Toolkit an addendum that contains additional details concerning special considerations for COVID-19 and mpox vaccines. This is available at www.cdc.gov/vaccines/hcp/admin/storage/toolkit/storage-handling-toolkit.pdf.

Last reviewed: July 26, 2023

Yes, COVID-19 vaccines and other routine vaccines, including influenza and RSV vaccines, may be coadministered on the same day, given in different syringes and at different anatomical sites. COVID-19 vaccines may also be given at any interval before or after any other vaccination.

Of note, 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 mpox prevention), regardless of which vaccine is administered first. However, use of Jynneos vaccine should be prioritized over ACAM2000 when co-administering a COVID-19 vaccine and an orthopoxvirus vaccine.

People, particularly adolescent or young adult males, who are recommended to be vaccinated against both mpox and COVID-19 might consider waiting 4 weeks between vaccines. 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 mpox or severe disease due to COVID-19 is increased, administration of mpox and COVID-19 vaccines should not be delayed.

Additional information is available from CDC: www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#timing-spacing-interchangeability.

Last reviewed: March 19, 2024

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