Efficacy of COVID-19 vaccine booster doses in older people.

Purpose: We provide here an updated analysis on efficacy of COVID-19 vaccine booster doses in older people (i.e., aged ≥ 80 years) based on ongoing Italian nationwide COVID-19 vaccination campaign.

Methods: Data were obtained from the COVID-19 national integrated surveillance program, made available and regularly updated by the Italian National Institute of Health.

Results: Compared to those who completed the COVID-19 vaccination cycle for ≥ 5 months (n = 2,385,897), those receiving booster doses (n = 1,549,747) had 75% lower risk of SARS-CoV-2 infection, 82-83% lower risk of COVID-19 hospitalization and ICU admission, and 81% lower risk of death. Administration of COVID-19 vaccine boosters generated also greater protection (between 63 and 87% higher) against all these same endpoints compared to early completing (i.e., < 5 months; n = 335,458) a primary COVID-19 vaccination cycle.

Conclusions: The administration of COVID-19 vaccine booster doses is advisable for reducing the risk of morbidity and mortality in older people.