Findings confirm safety of simultaneous COVID-19 and influenza vaccine administration

Results of a Phase IV study published in The Lancet find no safety concerns with coadministration of the COVID-19 vaccine and the influenza vaccine.

The multicenter, randomized controlled trial was designed to compare outcomes in U.K. adults who did and did not receive influenza vaccination as they were given a second dose of the Pfizer or AstraZeneca COVID-19 vaccine.

There were 679 participants in total, distributed across 6 cohorts dictated by which brand of COVID-19 vaccine they received and whether the influenza vaccine they received was the quadrivalent, trivalent, or recombinant quadrivalent formulation.

One-half of the volunteers were randomized to receive a concomitant administration of influenza vaccine and a second dose of COVID-19 vaccine at day 0 followed by placebo at day 21. The remaining participants were allocated to placebo plus a second dose of coronavirus vaccine at day 0 followed by influenza vaccine at day 21. At 6-week follow-up, investigators assessed the primary endpoint for one or more participant-reported solicited systemic reactions in the week following the first trial vaccination.

The researchers determined most systemic reactions to vaccination were mild or moderate in nature, with a similar incidence rate between the randomized groups. Because same-time vaccination against coronavirus and influenza maintains antibody responses to both without triggering safety flags, the study authors conclude that concomitant vaccination is appropriate and promises to lower the burden on health care services.