[COVID-19 pandemic: outcomes and mortality in inpatients related to vaccination]

Different COVID-19 vaccines were developed in a short time after the beginning of pandemics, reducing mortality, especially in high risk population. This was demonstrated in several studies, mostly retrospective or based in mathematical models. The objective was to compare mortality in inpatients with COVID-19 related to vaccination.

Longitudinal, prospective, comparative, observational study. Inpatients with COVID-19 diagnosis were included between 17/12/2021 and 23/02/22, in Hospital Nacional Prof. A Posadas and Hospital Interzonal General de Agudos Eva Perón.

Inpatients (245) were analyzed, finding an overall mortality of 25.3%, 16.8% in fully vaccinated patients (two or more doses with less than 150 days since the last dose until the COVID-19 test) and 31.9% in those with incomplete vaccination (unvaccinated, one dose or two or more doses with more than 150 days since the last dose) (p = 0.007), OR 2.31 (IC95; 1.25-4.28) for incomplete vaccination. Mortality was 32.2% in patients who developed pneumonia, 22.2% for fully vaccinated and 38% for incompletely vaccinated (p = 0.048), OR 2.15(IC95; 1.01-4.58). Mortality was associated with older age (70 vs. 59 years; p < 0.001), female sex (54.8% vs. 37.7%; p < 0.02) and oncologic disease (27.4 vs. 14.8%; p = 0.02). PESI score was higher in incompletely vaccinated (102.5 vs. 93, p = 0.05) and SOFA score was lower (2 vs. 3, p = 0.01). The necessary number to treat (NNT) to prevent one death was 7 patients for the overall sample (IC95;4-22) and 6 (IC95;3-106) for pneumonia.

This study constitutes a starting point for developing other investigations and raising awareness of medical community and people about the beneficial effects of vaccination.