Nosocomial outbreak of SARS-CoV-2 infection in a haematological unit – high mortality rate in infected patients with haematologic malignancies

Biernat, Monika M; Zińczuk, Aleksander; Biernat, Paweł; Bogucka-Fedorczuk, Aleksandra; Kwiatkowski, Jacek; Kalicińska, Elżbieta; Marciniak, Dominik; Simon, Krzysztof; Wróbel, Tomasz

BACKGROUND: Here we report nosocomial outbreak of COVID-19 among patients in a haematological unit. To our knowledge this is the first report from Central Europe comparing morbidity and mortality in infected and non-infected patients after exposure to SARS-CoV-2. METHODS: The outbreak involved 39 individuals: 19 patients and 20 health care workers. The SARS-CoV-2 test by nasopharyngeal swabs was performed by real-time RT-PCR. Exposed patients were divided into two groups: quarantine patients with and without COVID-19. All patients were prospectively examined at the following time points: 0, 7 days, 14 days, 21 days and 28 days after confirmation or exclusion of SARS-CoV-2. RESULTS: Infection was confirmed in a total of 5/20 health care workers and 10/19 patients. Among the patients positive for SARS-CoV-2 infection, the mortality rate was 36.8%. The probability of death in patients infected with SARS-CoV-2 increased 8-fold (p = 0.03). Bacterial, fungal, and viral co-infection significantly decreased survival in these patients (p < 0.05). Additionally, the probability of death was much higher in patients older than 40 years of age (p = 0.032). CONCLUSION: This study showed significantly higher mortality rate in COVID-19 patients with haematologic diseases compared to the non-infected patient group. Haematologic patients with COVID-19 have 50% less chance of survival.