Ramat Gan, Israel—Without question, one of the most common questions pharmacists will have to answer in the coming months is whether it is safe and effective to receive influenza and COVID-19 vaccines at the same time.

While the CDC has advised that coadministration is acceptable, questions persist. A new Israeli study published in the Journal of the American Medical Association Network Open provides additional information.

“COVID-19 and seasonal influenza vaccines were previously given separately, although their coadministration is warranted for vaccination adherence,” Sheba Medical Center–led researchers wrote, adding that limited data on coadministration have been published.

To remedy that, the study team compared the reactogenicity and immunogenicity of COVID-19 and influenza vaccinations administered together with those of COVID-19 vaccination alone. Included in the prospective cohort study were healthcare workers at a large tertiary medical center in Israel who received the Influvac Tetra (Abbott) influenza vaccine (2022/2023), the Omicron BA.4/BA.5–adapted bivalent (Pfizer/BioNTech) vaccine, or both.

Vaccination, which was offered to all employees and was coadministered or given separately, began in September 2022, and data were collected until January 2023.

The researchers were primarily focused on adverse effects following vaccine receipt, which were assessed by a digital questionnaire and specifically included any local symptoms; fever; weakness or fatigue; any systemic symptoms; and their duration. That group included 588 participants. In addition, an immunogenicity analysis outcome tracked postvaccination antispike immunoglobulin G (IgG) titer in 151 participants.

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

“In this cohort study of healthcare workers who received a COVID-19 vaccine, an influenza vaccine, or both, coadministration was not associated with substantially inferior immune response or to more frequent adverse events compared with COVID-19 vaccine administration alone, supporting the coadministration of these vaccines,” study authors pointed out.

Essentially, the study found that, compared with COVID-19 vaccination alone, the risk of systemic symptoms was lower and statistically insignificant in the coadministration group, while lower, statistically insignificant antispike IgG titers were found in the coadministration group. That means that neither reactogenicity nor immunogenicity was significantly different with the coadministration of the COVID-19 and seasonal influenza vaccines compared with the administration of COVID-19 vaccination alone.

The CDC and other organizations recommended coadministration in the 2022-2023 influenza season in hopes of increasing adherence to the vaccine and reducing the burden on the healthcare system.

“Moreover, data on the coadministration of the Omicron BA.4/BA.5–adapted bivalent booster (Pfizer-BioNTech) vaccine with SIV have not been published, to our knowledge,” the authors added. “The aim of this study is to compare the reactogenicity and immunogenicity of the COVID-19 Omicron BA.4/BA.5–adapted bivalent vaccine administered together with SIV [seasonal influenza vaccinations] with the reactogenicity and immunogenicity of this type of COVID-19 vaccination given alone in the context of a HCW [healthcare worker] population that had almost entirely previously received 1 or 2 COVID-19 vaccine booster doses.”

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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