Background: There have been concerns about COVID-19 vaccination safety among frail older individuals. We investigated the relationship between mRNA COVID-19 vaccination and mortality among individuals aged ≥70 years and whether mortality varies across four groups of health-services used.
Methods: In this nationwide cohort study, we included 688,152 individuals aged ≥70 years at the start of the Norwegian vaccination campaign (December 27, 2020). We collected individual-level data from the Norwegian Emergency Preparedness Register for COVID-19. Vaccinated and unvaccinated individuals were matched (1:1 ratio) on the date of vaccination based on sociodemographic and clinical characteristics. The main outcome was all-cause mortality during 21 days after first dose of mRNA COVID-19 vaccination. Kaplan-Meier survival functions were estimated for the vaccinated and unvaccinated groups. We used Cox proportional-hazards regression to estimate hazard ratios (HRs) of death between vaccinated and unvaccinated individuals, overall and by use of health services (none, home-based, short- and long-term nursing homes) and age group.
Results: Between December 27,2020, and March 31,2021, 420,771 older individuals (61.1%) were vaccinated against COVID-19. The Kaplan-Meier estimates based on the matched study sample showed a small absolute risk difference in all-cause mortality between vaccinated and unvaccinated individuals, with a lower mortality in the vaccinated group (overall HR 0.28 (95% CI: 0.24–0.31)). Similar results were obtained in analyses stratified by use of health services and age group.
Conclusion: We found no evidence of increased short-term mortality among vaccinated individuals in the older population after matching on sociodemographic and clinical characteristics affecting vaccination and mortality.
Published: 7 November 2022