Abstract
Introduction: This study aims to investigate the clinical impact of Omicron Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) infection on the clinical presentation of Coronavirus Disease 2019 (COVID-19) in the very old (≥80 years old) population. Methods: All patients aged 80 years or older, hospitalized from March 2020 to June 2023 with a SARS-CoV-2 infection in one of the 17 COVID-19 units in eight cities of Campania, southern Italy, were enrolled in a multicenter, observational, retrospective study. Results: 341 patients ≥ 80 years of age were included: 80 of them in the Omicron and 261 in the non-Omicron period. Patients admitted during the Omicron period were older (p = 0.0001) and more comorbid, showing more frequently arterial hypertension (p = 0.018), cardiovascular disease (p = 0.0001), chronic kidney disease (CKD) (p = 0.002), chronic obstructive pulmonary disease (COPD) (p = 0.001), and active cancer (p = 0.0001). Severe and critical outcomes were observed more often in the non-Omicron variant (p = 0.0001). Patients in the Omicron group did not show a significantly prolonged hospitalization time (p = 0.063) or a higher likelihood of death during hospitalization (p = 0.097). Discussion: In our study, despite the greater frailty of patients hospitalized during the Omicron period, the disease appeared less severe compared to previous waves, suggesting that the lower severity of the disease could be attributed to virological rather than population characteristics. These findings underscore the importance of prevention strategies for older people, as the administration of vaccination and early antiviral therapies in at-risk subjects.