Background: Maximizing influenza and COVID-19 vaccine administration prevents substantial morbidity and mortality. Data from several countries show that while uptake of the influenza vaccine remains stable, sharp declines occurred in COVID-19 vaccine administration since 2022. Whether the gap between influenza and COVID-19 vaccine coverage rates is consistent across age groups and countries is unclear.
Objectives: To compare influenza and COVID-19 vaccination rates among adults in US, Canada, England, France, Germany, Spain, and Italy by age groups.
Methods: Influenza and COVID-19 vaccine coverage rates among adults during the 2022-2023 winter season were obtained from national reporting agencies or population-based surveys. The cumulative end-of-season (May 2023) coverage rates for influenza and COVID-19 vaccines were calculated for each country, stratified by age (young adults: either 18-59 or 18-64, older adults: either ≥60 or ≥65 depending on influenza vaccine recommendations). Weighted averages were used to obtain combined estimates for each age stratum based on country-specific population structures. Differences in the coverage rate between the 2 vaccines by age group were evaluated.
Results: During the study period, influenza vaccine coverage rates ranged from 54.5% (US) to 76.2% (England) for older adults, and from 10.6% (Italy) to 39.8% (US) for young adults. During the overlapping period, COVID-19 vaccine coverage rates ranged from 14.3% (France) to 80.0% (England) for older adults, and from 1.1% (France) to 29.5% (US) for young adults. The influenza coverage outpaced COVID-19 coverage in majority of the countries and age groups examined. The difference between influenza and COVID-19 vaccine coverage in older adults was 41.9%, 39.3%, 25.9%, 14.4%, 7.7%, in France, Canada, Italy, Germany, and US, respectively, and in younger adults was 30.5%, 18.1%, 10.4%, 10.2%, 7.1%, in France, Germany, Canada, US, and Italy, respectively. Among older adults in England and Spain, COVID-19 coverage (80.0 % and 60.9%, respectively) was slightly higher than influenza vaccine coverage (76.2% and 60.7%, respectively). In general, while COVID-19 vaccine uptake significantly declined since the second half of 2022, flu vaccine coverage during the same period slightly increased.
Conclusions: In the 2022-2023 winter season, influenza vaccine coverage was substantially higher than COVID-19 vaccine coverage in multiple countries examined in this study. The gap was larger for older adults who are at highest risk for severe outcomes. Individuals receiving only 1 of the 2 vaccines represent opportunities to increase coverage and provide better population-level protection for influenza and COVID-19.
