Reactogenicity Comparable for Simultaneous, Sequential COVID-19, Flu Shots
By Elana Gotkine HealthDay Reporter
FRIDAY, Nov. 8, 2024 -- Reactogenicity is comparable for simultaneous and sequential administration of mRNA COVID-19 and influenza vaccines, according to a study published online Nov. 6 in JAMA Network Open.
Emmanuel B. Walter, M.D., M.P.H., from the Duke University School of Medicine in Durham, North Carolina, and colleagues compared the reactogenicity, safety, and changes in health-related quality of life after simultaneous versus sequential receipt of the mRNA COVID-19 vaccine and the quadrivalent inactivated influenza vaccine (IIV4) in a randomized clinical trial. A total of 335 persons were randomly assigned to receive simultaneous intramuscular administration of IIV4 and mRNA COVID-19 vaccines, with placebo administered two weeks later, or sequential administration of mRNA COVID-19 vaccine plus placebo, followed by IIV4 administration two weeks later (169 and 166 participants, respectively).
The researchers found that the primary composite reactogenicity outcome (proportion with fever, chills, myalgia, and/or arthralgia of moderate or greater severity within seven days after vaccination) was noninferior in the simultaneous versus the sequential group (25.6 versus 31.3 percent). After each visit separately, the respective proportions were similar (visit 1: 23.8 versus 28.3 percent; visit 2: 3.0 versus 5.4 percent). There were no significant differences seen between the groups in terms of participants with adverse events, serious adverse events, and adverse events of special interest.
"This trial lends support to the option of simultaneous administration of these vaccines, which is a strategy to achieve high levels of vaccination coverage during anticipated periods of increased influenza and SARS-CoV-2 virus transmission," the authors write.
Several authors disclosed ties to the pharmaceutical industry.
Disclaimer: Statistical data in medical articles provide general trends and do not pertain to individuals. Individual factors can vary greatly. Always seek personalized medical advice for individual healthcare decisions.
© 2025 HealthDay. All rights reserved.
Posted November 2024
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