ISSN: 2471-9552
Antonio Faraone, Giulia Scocchera, Tommaso Picchioni, Francesca Palandri, Gabriele Nenci, Elisa Grifoni, Luca Masotti, Alessandro Morettini, Alberto Fortini
Background: The benefits of prior vaccination in patients hospitalized for moderate to severe COVID-19 during the Omicron surge are not well defined. We assessed characteristics and outcomes of a cohort of COVID-19 inpatients by their vaccination status.
Methods: Patients admitted with moderate to severe COVID-19 between December 20, 2021 and March 31, 2022 were divided into 3 groups: 1) unvaccinated, 2) vaccinated with 2 doses, and 3) vaccinated with 3 doses. The main outcome was a composite of ICU transfer, mechanical ventilation or in-hospital death (poor outcome).
Results: We enrolled 446 patients (median age 78 years, IQR 65-85.3), of which 168 (37.7%) unvaccinated, 113 (25.3%) vaccinated with 2 doses and 165 (37%) vaccinated with 3 doses. Vaccinated patients had a higher comorbidity burden and were older (3-dose vaccinees) compared to unvaccinated ones. The rate of poor outcome was not significantly different between groups (19.6%, 15% and 22.4% for unvaccinated, 2-dose and 3-dose vaccinated patients, respectively). Multivariable regression analysis did not show a protective effect of vaccination, either with 2 or 3 doses. In the subset of 205 patients over 80 years, a 3-dose vaccination was inversely associated with poor outcome (OR 0.47 [95% CI 0.23-0.95], p=0.04).
Conclusion: The rate of poor outcome was not associated with vaccination status and was similar between study groups, despite a higher risk profile displayed by 2-dose and 3-dose vaccinees. Prior vaccination with 3 doses reduced the risk of poor outcome compared to no vaccination in the subset of patients older than 80 years.