Risk of mortality among older adults hospitalized for COVID-19 with and without vaccination in Mexico

Background: COVID-19 mortality increases exponentially with age, with age being the main predictor of fatal outcomes. In older adults, susceptibility to infections is associated with immunosenescence. The SARS-CoV-2 vaccines approved for emergency use were authorized based on interim analyses of phase III clinical trials, which demonstrated acceptable efficacy and safety in the context of the pandemic. However, the efficacy observed under real-life conditions may differ from theoretical efficacy due to population heterogeneity. Objective: This study aimed to evaluate the risk of COVID-19–related mortality in hospitalized older adults with or without vaccination during the pandemic. Material and methods: A cross-sectional study was designed to evaluate the risk of COVID-19–related mortality in hospitalized older adults with or without vaccination. This study used patient records from a Mexican Social Security Institute (IMSS) hospital in Aguascalientes, Mexico. The study included 1516 adults aged 60 years or older who were hospitalized with COVID-19 between January 2021 and March 2022. Results: The COVID-19 mortality rate in hospitalized older adults was 48.4%. Mortality was 16% higher in men than in women. Multivariate analysis showed that the risk of a vaccinated older adult dying from COVID-19 is 34% lower than that of an unvaccinated older adult (OR = 0.66; 95% CI: 0.52 to 0.85). Conclusions: The study demonstrates the importance of older adults receiving the COVID-19 vaccine to reduce their risk of mortality.