Addressing Concerns About Administering COVID-19 Vaccines With Other Vaccines

Note: While this section was written with COVID-19 vaccines in mind, many of the general principles apply to other vaccines as well. Individual vaccines may vary in their antigenic components or dosage forms, but the principles of human behavior and good communication skills transcend most differences between vaccines.

The Issue

Many Americans need vaccination against COVID-19 and also against other serious diseases (e.g., influenza, RSV, measles, HPV). Some people may be concerned about the safety of vaccines administered simultaneously. Others may balk at the prospect of receiving what they think might be “too many” vaccines. People also may have questions about the optimal timing of different vaccines.

Sound Bites

• Simultaneous administration of vaccines—administering more than one vaccine on the same day, at different anatomic sites, in separate syringes—is safe and recommended as a vaccination “best practice.”
• COVID-19 vaccines may be administered without regard to the timing of most other vaccines.
• If the urgency to become immune is not a consideration, it may be preferable for some people (particularly male adolescents and young adult men) to wait 4 weeks after vaccinations such as the mpox vaccine (Jynneos) before receiving COVID-19 vaccination because of possible heightened risk for myocarditis and pericarditis. In the setting of an orthopoxvirus outbreak like monkeypox, no minimum interval is necessary.
• Getting immunity from a COVID-19 shot or seasonal influenza vaccine is more important than trying to time the spacing between vaccinations perfectly.

What We Know

The availability and need for multiple types of vaccination raise questions about the timing and safety of vaccine coadministration. Some people are inclined to “pick and choose” among needed vaccines. Others are dealing with “vaccine fatigue.”¹

Fortunately, these questions have straightforward answers. Simultaneous administration of vaccines—defined by the Centers for Disease Control and Prevention (CDC) as administering more than one vaccine on the same clinic day, at different anatomic sites, in separate syringes—is both safe and recommended as a vaccination “best practice.”² Administering multiple vaccines during a single visit increases the probability that a child, adolescent, or adult will develop immunity and be up to date on recommended immunization.

Simultaneous Administration of COVID-19 Vaccines With Other Vaccines

The CDC states that COVID-19 vaccines may be administered without regard to the timing of other vaccines.³ Orthopoxvirus vaccines, like mpox vaccine, are an exception; (see additional considerations in the section below on COVID-19 Vaccine and Orthopoxvirus Vaccine).

Experimental evidence and extensive clinical experience with other vaccines show similar immune responses and adverse event profiles when vaccines are administered simultaneously as when they are administered alone.² Studies that compared coadministration of COVID-19 and seasonal influenza vaccines with separate administration of these vaccines found similar levels of immunogenicity and similar or slightly higher reactogenicity; no specific safety concerns were identified.³

In accordance with general best practices, the CDC recommends routine administration of all age-appropriate doses of vaccines simultaneously for children, adolescents, and adults for whom no specific contraindications exist at the time of the health care visit.³ Each injection should be administered in a different site, such as a different limb or an injection site in the same limb, with injection sites separated by 1 inch or more if possible. Other reactogenic vaccines (e.g., meningococcal B [MenB]; tetanus, diphtheria, and acellular pertussis [Tdap]; recombinant zoster) should be administered in different limbs whenever possible.⁴ The anterolateral thigh (vastus lateralis muscle) may be used in adults as well as children.

Pharmacists who need additional information can access extensive CDC guidance on Multiple Injections/Coadministration of Vaccines. 

COVID-19 Vaccine and Orthopoxvirus Vaccine

In July 2022, the Director-General of the World Health Organization declared the escalating global monkeypox outbreak a Public Health Emergency of International Concern. In an orthopoxvirus outbreak like monkeypox—when orthopoxvirus vaccination is recommended for prophylaxis in high-risk individuals—the CDC states that no minimum interval between COVID-19 vaccination and orthopoxvirus vaccination is necessary.³

If urgency to induce immunity is not a consideration, it may be preferable for people (particularly male adolescents and young adult men) to wait 4 weeks after orthopoxvirus vaccination before receiving a COVID-19 vaccine because of the possible heightened risk for myocarditis and pericarditis.³

Optimal Timing of COVID-19 Vaccine and Influenza Vaccine

The CDC recommends September and October as good times to vaccinate most Americans against influenza, with everyone ideally vaccinated by the end of October.⁵ Children needing two doses and pregnant women may be vaccinated before September. Many people will ask whether to get a COVID-19 vaccine and flu shots separately or simultaneously.

Experts advise that getting the shots is more important than trying to time them. As long as minimum dosing intervals are not violated, it is better to administer multiple vaccines at a convenient time than to risk the patient not returning for recommended vaccination and remaining vulnerable.

This approach holds true for simultaneous administration of any vaccines with the COVID-19 vaccine. When patients seek a COVID-19 vaccine, pharmacists can use the opportunity to alert patients to other recommended vaccines (e.g., pneumococcal vaccine, zoster vaccine, human papillomavirus vaccine) and encourage administration during the same appointment. Conversely, pharmacists can recommend COVID-19 vaccine to patients or parents who visit the pharmacy for the administration of other vaccines for themselves or their children.

Pharmacists who need to discuss the administration of multiple vaccines with parents can find detailed information on the Immunize.org website and the resource “Too Many Vaccines? What You Should Know” developed by the Vaccine Education Center at Children’s Hospital of Philadelphia.^{6, 7}

References

1. Su Z, Cheshmehzangi A, McDonnell D, et al. Mind the “vaccine fatigue.” Front Immunol. 2022;13:839433. doi: 10.3389/fimmu.2022.839433
2. Centers for Disease Control and Prevention. Vaccine recommendations and guidelines of the ACIP. Timing and spacing of immunobiologics: general best practice guidelines for immunization.. Updated August 1, 2023 . Accessed February 27, 2024. https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/timing.html
3. Centers for Disease Control and Prevention. Use of COVID-19 vaccines in the United States: interim clinical considerations. Reviewed April 4, 2024. Accessed April 12, 2024. https://www.cdc.gov/vaccines/covid-19/clinical-considerations/interim-considerations-us.html#covid-vaccines
4. Centers for Disease Control and Prevention. Vaccine administration: administer the vaccine(s). Updated September 8, 2021. Accessed September 6, 2022. https://www.cdc.gov/vaccines/hcp/admin/administer-vaccines.html
5. Centers for Disease Control and Prevention. Key facts about seasonal flu vaccine. Reviewed March 22, 2024. Accessed April 12, 2024. https://www.cdc.gov/flu/prevent/keyfacts.htm
6. Immunize.org. How to administer multiple intramuscular vaccines to adults during one visit. December 4, 2023. Accessed February 27, 2024. https://www.immunize.org/wp-content/uploads/catg.d/p2030.pdf
7. Children’s Hospital of Philadelphia Vaccine Education Center. Too many vaccines? What you should know. Winter 2018. Accessed September 6, 2022. https://media.chop.edu/data/files/pdfs/vaccine-education-center-too-many-vaccines.pdf

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