Objectives: To compare, in a real-world scenario, the protective effect of vaccination and previous laboratory-confirmed symptomatic infection on the risk of COVID-19 pneumonia.
Methods: A retrospective study was conducted and 46,998 adults with laboratory-confirmed COVID-19 were enrolled. Risk ratios (RRs) and 95% confidence intervals (CIs) were used to evaluate the effect of the evaluated exposures on the risk of pneumonia.
Results: In multiple analysis and after adjusting by reinfection status, vaccinated participants were at reduced risk of developing pneumonia (RR = 0.974, 95% CI 0.965-0.983). The association of having had a previous infection was not significant (RR = 1.001, 95% CI 0.969-1.034).
Conclusion: Our results suggest, and if later replicated, that COVID-19 vaccines provide better protection against pneumonia than previous symptomatic infections. Therefore, offering vaccination to all eligible subjects despite past COVID-19 infections might be relevant to reducing the pandemic-related burden.
Keywords: COVID-19; COVID-19 Vaccines; Pneumonia; SARS-CoV-2.
Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.