COVID-19 vaccine safety and effectiveness at 3 months in institutionalized old people.

Background: Older age and associated comorbid conditions increase the risk of severe form of COVID-19 and death. The SARS-CoV-2 vaccination campaign began in France in December 2020 targeting institutionalized older population before having been evaluated in this population. The objective of our study was to assess the tolerability of vaccination 21 days (D21) and 90 days after the first vaccination (D90) in institutionalized old people. Secondary objective was to assess its effectiveness (mortality, hospitalization and occurrence of COVID) at D21 and D90.

Methods: People living in nursing homes or in long-term hospitalization facilities in France were included 12-2020-06-2021. They were divided into SARS-CoV-2 vaccinated and unvaccinated groups. Vaccine tolerability was prospectively assessed by the occurrence of health events at D21 and D90 (local and systemic side effects, geriatric syndromes, cardiovascular events). Vaccine efficacy was assessed by the occurrence of COVID-19 and serious adverse events (unscheduled hospitalization and all-cause mortality).

Results: The mean age of the 2595 participants was 86 years, 83% received COVID-19 vaccine. There were no significant difference between the vaccinated and unvaccinated for systemic or local adverse events at D21 and D90. At D90, vaccinated participants had significantly fewer SARS-CoV-2 infections (odds ratio (95% confidence interval) = 0.35 (0.22-0.58)), fewer deaths or hospitalizations (0.50 (0.31-0.81)), fewer cardiovascular events (0.28 (0.12-0.64)) and fewer pressure ulcers (0.38 (0.17-0.88)).

Conclusions: In this prospective cohort study, COVID-19 vaccine in a very old institutionalized geriatric population had a reassuring safety profile and a protective effect on COVID-19, hospitalizations and deaths, cardiovascular events and pressure ulcers.