THURSDAY, July 2, 2026 (HealthDay News) -- Same-day administration of COVID-19 and influenza vaccines is not associated with increased risk for adverse events, according to a study published online June 30 in the Annals of Internal Medicine.
Yan Xie, Ph.D., from VA St. Louis Health Care System, and colleagues examined 90-day risks for adverse events after coadministration of COVID-19 and influenza vaccines compared with influenza vaccination alone in a target trial emulation. Data were included for 705,124 participants receiving COVID-19 and seasonal influenza vaccines and 1,813,205 participants receiving only an influenza vaccine between Sept. 1, 2022, and Aug. 26, 2025. Ninety-day risks were examined for 46 adverse events grouped into three composite outcomes: tier 1 (serious or life-threatening), tier 2 (clinically significant), and tier 3 (less severe or self-limiting).
The researchers found that the risks were similar between groups for all three composite outcomes. Of the 46 individual adverse events, nominal statistical significance was seen for two tier-3 risks: syncope and tinnitus (risk ratios, 1.09 and 0.95, respectively); after correcting for multiple comparisons, no risks were statistically significant. Neither composite nor individual event estimates supported between-group differences in risk in period-stratified analyses.
"The findings support the short-term safety of coadministration in older adults and may help inform ongoing vaccine policy discussions and individual risk–benefit assessments," the authors write.
Two authors disclosed ties to the pharmaceutical industry.
