Co-administration of COVID-19 vaccines with other vaccines


Argentina: The National Commission on Immunizations (CoNaIn) of Argentina's Ministry of Health, in furtherance of the goals set forth in its national vaccination strategy, issued a recommendation on the co-administration of vaccines, providing for co-administration of COVID-19 vaccines with any other vaccine in the National Vaccination Schedule. The recommendation allows for administering the vaccines on the same or different days, and does not require an interval between doses. The goal is to take advantage of all opportunities for vaccination, an approach aligned with various scientific societies, agreed to by ministers of the country's 24 jurisdictions, and consistent with available evidence and the recommendations issued by other countries.  


United States: Studies are being planned and conducted to evaluate the safety and immunogenicity of coadministering COVID-19 vaccines with other vaccines. Extensive research on the simultaneous administration of the most widely used live and inactivated vaccines has demonstrated seroconversion rates and rates of adverse reactions similar to those observed when the vaccines are administered separately.

It is not known whether the reactogenicity of COVID-19 vaccines is increased with co-administration, including with other vaccines known to be more reactogenic, such as adjuvanted vaccines. The CDC believes that COVID-19 vaccines can be administered without regard to the timing for administering other vaccines. This includes simultaneous administration of COVID-19 vaccine and other vaccines on the same day.  

When deciding whether to administer one or more vaccines with a COVID-19 vaccine, vaccination providers should consider whether the patient is behind or at risk of becoming behind on recommended vaccines, the risk to the patient of vaccine-preventable disease (e.g., during an outbreak or occupational exposures), and the reactogenicity profile of the vaccines. If multiple vaccines are administered at a single visit, each injection should be administered in a different injection site. For adolescents and adults, the deltoid muscle can be used for more than one intramuscular injection administered at different sites in the muscle. It is important to document the vaccines given, along with the dosage, batch number, and expiration date of each vaccine.

In administering the vaccines, it is recommended that the injection sites be separated, if possible, by at least one inch (2.5 cm), and that vaccines that are more likely to cause local reactions be administered in different limbs.  



United Kingdom: In the absence of information on the co-administration of COVID-19 vaccines with other vaccines, first principles would suggest that interference between inactivated vaccines with different antigenic content is likely to be limited. Based on experience with other vaccines, any potential interference is most likely to result in slightly attenuated immune response to one of the vaccines. There is no evidence of any safety concerns, although it may make the attribution of any adverse events more difficult.

Considering that the COVID-19 vaccines of Pfizer-BioNTech, AstraZeneca, and Moderna are considered inactivated, where individuals in an eligible cohort present with having recently received another inactivated or live vaccine, COVID-19 vaccination should still be given. The same applies for most other live and inactivated vaccines where COVID-19 vaccination has been administered first, or where a patient presents requiring two vaccines.  It is generally better for vaccination to proceed in order to avoid any further delay in protection, and to avoid the risk of the patient not returning for a subsequent appointment.  

An exception to this is the live attenuated shingles vaccination, where a seven-day interval should ideally be observed, given the possibility that an inflammatory response to the COVID-19 vaccine may reduce the response to the live virus.  

Studies are currently underway to support co-administration of COVID-19 vaccines in the 2021–2022 season.  

When co-administration of vaccines does occur, patients should be informed about the likely timing of potential adverse events relating to each vaccine. 


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