Outcomes of patients with COVID-19 hospitalized during the fourth pandemic wave in relation to their clinical features and vaccination status

This study aims to observe the clinical characteristics and outcomes of recovered patients from coronavirus disease 2019 (COVID-19) related to the vaccination status. We examined results of 205 COVID-19-recovered patients from 15 December 2021 to 1 March 2022 in two hospitals of Local Health Authority of Alessandria (Italy) during the fourth pandemic wave. 77% of patients were hospitalized for acute respiratory failure (ARF) with radiological pneumonia pattern (recovered for COVID), 23% for other causes with occasional positivity finding (recovered with COVID). 32% of patients were not vaccinated for SARS-CoV-2, 37% had three doses, 25% two doses, 5% only one dose. All patients without vaccination were hospitalized for ARF and they had a 7 times higher risk of hospitalization than the vaccinated. 60% of all patients had ≥3 comorbidities, of these 50% was vaccinated with three doses. In the fourth pandemic wave compared to the other not all patients were hospitalized for ARF and pneumonia and the presence of comorbidities ≥3 is a risk factor for hospitalization regardless of vaccination status. This justifies the administration of the fourth dose to frail patients.