Retrospective study of the effect of vaccination against SARS-CoV-2 in seriously ill patients admitted to an intensive care unit

Abstract

Background and objectiveOur study aims to compare the clinical and epidemiological characteristics, length of stay in the ICU, and mortality rates of COVID-19 patients admitted to the ICU who are fully vaccinated, partially vaccinated, or unvaccinated. Patients and methodsRetrospective cohort study (March 2020–March 2022). Patients were classified into unvaccinated, fully vaccinated, and partially vaccinated groups. We initially performed a descriptive analysis of the sample, a multivariable survival analysis adjusting for a Cox regression model, and a 90-day survival analysis using the Kaplan-Meier method for the death time variable. ResultsA total of 894 patients were analyzed: 179 with full vaccination, 32 with incomplete vaccination, and 683 were unvaccinated. Vaccinated patients had a lower incidence (10% vs. 21% and 18%) of severe ARDS. The survival curve did not show any differences in the probability of surviving for 90 days among the studied groups (P=.898). In the Cox regression analysis, only the need for mechanical ventilation during admission and the value of LDH (per unit of measurement) in the first 24h of admission were significantly associated with mortality at 90 days (HR: 5.78; 95% CI: 1.36–24.48); P=.01 and HR: 1.01; 95% CI: 1.00–1.02; P=.03, respectively. ConclusionsPatients with severe SARS-CoV-2 disease who are vaccinated against COVID-19 have a lower incidence of severe ARDS and mechanical ventilation than unvaccinated patients.