The Characteristics of Health Care Workers with COVID-19 and Relationship Between COVID-19 Mortality and BCG/Tuberculosis History: a multi-center study

Background Today, COVID-19 pandemic has brought countries’ health services into sharp focus. Despite the low incidence of cases(1.2%) and high mortality rate(2.4%) among Turkish population, the low mortality rate(0.3%) despite the high incidence(11.5%) declared in healthcare workers drew our group’s attention. Therefore, we aimed to report the characteristics of infected health-care workers and investigate the relationship between BCG vaccine and tuberculosis history with COVID-19 mortality in infected health-care worker population. Method This study was conducted in three hospitals to assess the clinical presentations, disease severity and correlation with BCG vaccine and tuberculous history in COVID-19 positive health-care workers by an online questionnaire platform. The relationship between characteristics and tuberculosis history were investigated according to hospitalization status of the patients. Result Total of 465 infected healthcare workers included in the study. The rate of history of direct care and contact to tuberculosis patient, presence of previous tuberculosis treatment and BCG scar, presence of radiological infiltrations was significantly higher in hospitalized healthcare workers. The ratio of direct care and direct contact to the patient with tuberculosis, and presence of family history of tuberculosis were statistically significantly higher in patients with radiological infiltrations. Conclusion Although COVID-19 risk and incidence are higher among healthcare workers compared to the normal population due to higher virus load, this study brings evidence for the fact that the lower mortality rate seen in infected healthcare workers might be due to healthcare workers’ frequent exposure to tuberculosis bacillus and the mortality-reducing effects of BCG vaccine, despite the higher hospitalization rate and radiological infiltrations due to over-triggered immune system.