Clinical characteristics and outcomes of nosocomial COVID-19 in Turkey: A retrospective multicenter study

Objective: To identify the clinical characteristics and outcomes of hospital-acquired SARS-CoV-2 infection during the vaccination period nationwide in Turkey. Methods: COVID-19 patients followed in the pandemic services across Turkey between January 1, 2021, and March 31, 2022 were investigated retrospectively. Nosocomial COVID-19 was defined as a patient neither diagnosed with COVID-19 nor suspected COVID-19 at the hospital admission and was confirmed COVID-19 >= 5 days after hospital admission. The primary outcome of this study was in-hospital mortality; demographic features and vaccination status was compared between survivors and non survivors. Results: During the study period, 15 573 COVID-19 patients were followed in 18 centers and 543 (3.5%) patients were nosocomial COVID-19. Most patients with nosocomial COVID-19 (80.4%) were transferred from medical wards. 162 (29.8%) of the patients with nosocomial COVID-19 admitted to the intensive care unit due to disease severity and 138 (25.4%) of the patients died during hospital stay. Advanced age (>= 65 years) and number of comorbid diseases (>= 2) was found to be associated with mortality in nosocomial COVID-19 (OR 1.74, 95% CI 1.11-2.74 and OR 1.60, 95% CI 1.02-2.56, respectively). Vaccination was associated with survival in nosocomial COVID-19 (OR 0.25, 95% CI0.16-0.38). Conclusions: Patients with nosocomial COVID-19 had increased admission to intensive care units and higher mortality rate. Vaccination can decrease the in-hospital mortality rate.