Lower age is linked to reduced uptake of influenza and COVID-19 vaccination

Presented by

Ms Cecilie Seeger-Skaaning, Statens Serum Institut, Denmark

Conference

ESCMID Vaccines 2025

Lower age and country of origin were found to be key determinants of reduced uptake of both influenza and COVID-19 vaccination among pregnant women and individuals aged <65 years with comorbidities in Denmark, according to an analysis presented by Ms Cecilie Seeger-Skaaning (Statens Serum Institut, Denmark) at the ESCMID Vaccines 2025 conference.

The study used data from national health registries to link groups to seasonal vaccinations at an individual level and identified 54,559 pregnant women and 491,403 individuals <65 years with chronic conditions (≥2 hospital contacts for selected chronic conditions).

A total of 26.0% and 17.0% of pregnant women received influenza and COVID-19 vaccines, respectively. Among individuals <65 years with chronic conditions, 31.3% and 21.0% received influenza and COVID-19 vaccines, while vaccination uptake was almost 80% for both vaccines in individuals aged ≥65 years. Among pregnant women, vaccine uptake increased with age, showing a 4- to 5-fold increase in odds of vaccination for the 35-45 vs 18–24 age group. Similarly, the odds of vaccination uptake increased with age in individuals <65 years with chronic conditions, with adjusted odds ratios (ORs) of 6.38 (95% CI 6.20-6.55) for influenza and 9.14 (95% CI 8.81–9.48) for COVID-19 vaccination when comparing the 60–64 with the 18–29 years age group. Another determinant of lower uptake included having a country of origin outside of Denmark in both populations.

“Vaccination uptake in pregnant women and individuals <65 years with chronic conditions is much lower than in adults aged 65 and older”, said Ms Seeger-Skaaning. “We see that influenza uptake is consistently higher than COVID-19 vaccine uptake among all age groups, and age and country of origin are determinants for vaccination.” However, Ms Seeger-Skaaning added that a pilot program using tailored invitations showed increased vaccination regardless of age or country of origin, a strategy which could be used in the future to increase uptake.

Moustsen-Helms IR, et al. Determinants of influenza and COVID-19 vaccine uptake among pregnant women and high-risk individuals. 6^th ESCMIDVaccines, 10–13 September 2025, Lisbon, Portugal.

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