COVID-19 and Flu Shot Coadministration Delivers Positive Results

In the United States, the annual flu season is just starting at the same time U.S. government agencies are expected to announce recommendations for new COVID-19 vaccines.

As millions of people approach their trusted pharmacists for a flu shot, many wonder if the coadministration of a COVID-19 vaccine is safe and efficacious.

A new Original Investigation published by the peer-reviewed journal The JAMA Open Network on September 8, 2023, offered reassuring news for older adults.

This prospective cohort study included healthcare staff who were vaccinated against COVID-19 and/or influenza. Compared with COVID-19 vaccination alone, the risk of systemic symptoms was lower and statistically insignificant in the coadministration group.

And lower, statistically insignificant anti-spike IgG titers were found in the coadministration group.

Findings from previous immunogenicity and correlates of protection studies suggest that changes in IgG titers to such an extent did not significantly impact vaccine effectiveness, vaccine effectiveness against substantially symptomatic disease, or a SARS-CoV-2 betacoronavirus diagnosis risk.

This new study included two cohorts for 2 separate analyses.

The reactogenicity analysis included 588 participants (of 649 questionnaire responders): 85 in the COVID-19 vaccine–alone group (median [IQR] age, 71 [58-74] years; 56 [66%] female); 357 in the influenza vaccine–alone group (median [IQR] age, 55 [40-65] years; 282 [79%] female); and 146 in the coadministration group (median [IQR] age, 61 [50-71] years; 81 [55%] female).

The immunogenicity analysis included 151 participants: 74 participants in the COVID-19 vaccine group (median [IQR] age, 67 [56-73] years; 45 [61%] female) and 77 participants in the coadministration group (median [IQR] age, 60 [49-73] years; 42 [55%] female).

Compared with COVID-19 vaccination alone, the risk of systemic symptoms was similar in the coadministration group (odds ratio, 0.82; 95% CI, 0.43-1.56).

The geometric mean titers in the coadministration group were estimated to be 0.84 (95% CI, 0.69-1.04) times lower than in the COVID-19 vaccine–alone group.

A potential limitation of our study is that the study population is composed of relatively healthy people and, therefore, may not be fully generalizable to more vulnerable populations. Another limitation is that we only assessed the immunogenicity against the SARS-CoV-2 betacoronavirus and not the immunogenicity against influenza, which theoretically might be differently impacted by the coadministration of the two vaccines, wrote these researchers.

The study was funded by internal funding of The Sheba Pandemic Preparedness Research Institute and not sponsored or funded by any commercial entity.

Regarding younger people, the U.S. CDC recently conducted a Clinician Outreach and Communication Activity call presenting an update for Pediatric Providers regarding Influenza Prevention and Treatment in Children Recommendations.

On August 31, 2023, the CDC staff endorsed the coadministration of flu shots with other vaccines for children.

The CDC says manufacturers have projected to supply as many as 156.2 million to 170 million doses of influenza vaccines for the 2023-2024 flu season.