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

Abstract

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.

Keywords: COVID-19; Haematological malignancies; Hospital-acquired infection.

Fig. 1

Overall survival according to haematologic malignancies diagnosis in patients with COVID-19. AML – acute myeloid leukaemia, MDS – myelodysplastic syndrome, lymphoid malignancies: T-cell lymphoma, B-cell lymphoma, multiple myeloma, acute lymphoblastic leukaemia

Fig. 2

Overall survival according to COVID-19 diagnosis in patients with haematological malignancies involved in outbreak.

Fig. 3

The PCA analysis presented in the pca1 vs. pca2 load diagram. The variables such as CRP, number of lymphocytes, age, time from infection from death, number of survivors and deceased patients and number of infected were analysed. After analysis, the highest probability of death is noted in the group of patients over 40 years of age with COVID-19, who had high CRP and d-dimers in the first 7 days of infection.

Fig. 4

The PCA analysis presented in the pca1 vs. pca2 load diagram. The variables such as dyspnoea, cough, gender, type of haematological malignancies and number of infected patients were analysed. After the analysis, the highest probability of death is noted in the group of women with AML/MDS with COVID-19 who had symptoms of dyspnoea and cough in the first 7 days of infection.

Fig. 5

The PCA analysis presented in the pca1 vs. pca2 load diagram. The variables such as age, hypertension, diabetes t.2, VTE, gender, type of haematological malignancies and number of infected patients were analysed. After the analysis, the highest probability of death is noted in the group of women older than 40 years of age with COVID-19 and hypertension. The presence of VTE and/or diabetes also increases the risk of death. VTE – venous thromboembolism, Diab.t2 – diabetes type 2, HT – hypertension, AML – acute myeloid leukaemia, MDS – myelodysplastic syndrome, lymphoid malignancies: T-cell lymphoma, B-cell lymphoma, multiple myeloma, acute lymphoblastic leukaemia