Despite the effectiveness of vaccination in preventing severe COVID-19, some individuals remain at risk. The study goal was to determine risk factors for COVID-19 requiring hospital admission. A case-control study was conducted in Porto Alegre, Brazil. Vaccinated adults with confirmed SARS-CoV-2 infection from February 2021 to March 2023 were eligible. Hospitalized patients (cases) and outpatients with non-severe infections (control group) were time-matched in a 1: 1 ratio. Moreover, we followed hospitalized patients (cases) to evaluate factors related to 30-day mortality and/or ventilation support. We included 364 patients: 182 cases and 182 controls. Age > 60 years (odds ratio OR 3. 98 95% confidence intervalCI 2. 23-7. 19), male sex (OR 3. 07 95%CI 1. 78-5. 40), diabetes mellitus (OR 4. 61 95% CI 2. 08-11. 08), cardiovascular disease (OR 4. 07 95%CI 1. 73-10. 64), lung disease (OR 3. 06 95%CI 1. 39-6. 94), obesity (OR 3. 39 95%CI 1. 29-9. 73), and previous infection (OR 0. 19 95%CI 0. 06-0. 51) were independently related to COVID-19 hospital admission. In the arm of hospitalized patients, the number of vaccine doses (OR 0. 53 95%CI 0. 39-0. 73) was a protective factor against 30-day mortality and/or ventilation support, whereas obesity (OR1. 62 95%CI 1. 19-2. 20) was a risk factor. Health policies should consider focusing on these risk populations for targeted interventions, such as additional boosters, early treatment and prophylaxis.
Sorio et al. (Sun,) studied this question.