Influence of influenza vaccine and comorbidity on the evolution of hospitalized COVID-19 patients

The COVID-19 coronavirus disease outbreak is evolving around the world. The aim of this study is to evaluate the association between influenza vaccination and the risk of mortality in hospitalized COVID-19 patients, as well as other risk factors.

Retrospective observational study. This study was conducted among hospitalized patients with COVID-19 at Hospital La Mancha Centro between March 5 and 25, 2020. Information on influenza vaccination was extracted from electronic medical records. We used a multivariate logistic regression to explore the association between influenza vaccination and mortality from COVID and other risk factors.

410 patients were included. Influenza vaccine had no effect among COVID-19 hospitalized patients [OR: 1.55 (95%CI: 0.96 - 2.48; p=0.071)]. Increasing hospital mortality was associated with older age [OR: 1.05 (95% CI 1.02-1.07), per year increase; p<0.001)], Charlson ≥3 [OR: 1.84 (95%CI: 1.07-3.15, p=0.027)] and heart failure on admission [OR: 6 (IC95%: 1.6 - 21.7; p=0.007)] CONCLUSIONS: Influenza vaccine had no effect among COVID-19 hospitalized patients. The risk factors identified were older age, higher comorbidity and heart failure on admission.