Evaluation of BCG scar and tuberculosis skin tests in health care workers with and without COVID-19

Introduction: The prevalence, morbidity and mortality of novel coronavirus infection is reported to be lower in countries with routine Bacille Calmette-Guerin (BCG) vaccination schedule But it is not clear yet whether BCG vaccination has a protective effect on COVID-19 infection on groups under risk such as healthcare workers (HCW) and elderly In this study we evaluated the relation of BCG vaccination, tuberculosis skin test (TST) result and COVID-19 in HCW Materials and methods: The study was designed as retrospective, case control study in the health care personnel working in pandemics clinics The whole cases were divided to two groups as COVID-19 group (with a history of SARS CoV-2 infection) and control group (who did not suffer from COVID-19) Demographic data, TST, BCG scar and history for SARS CoV-2 infection were collected from hospital staff working in pandemics clinics between March 15, 2020 and November 15, 2020 In the cases suffered from COVID-19 the clinical and laboratory features and radiological severity of pneumonia -if present- and time for polymerase chain reaction (PCR) conversion in nasopharyngeal swab were recorded All parameters were compared between two groups Results: 148 HCW were included to the study COVID-19 group included 68 (66 7%) females and 34 (33 3%) males (mean age: 36±9 years) and control group included 23 (50%) females and 23 (50%) males (mean age: 35±8 years) The mean value of TST for whole group was 6 3±7 6 mm and similar between groups The number of cases with BCG scars were significantly more in COVID-19 group (p=0 04) In COVID-19 group 29 (28 4%) of the cases were hospitalized while only 1(1%) suffered from severe disease None of the cases were died No relation was found between TST value, positivity and presence of BCG scar with the laboratory parameters, clinical features, radiological severity and hospitalization rate (p>0 05) The mean PCR conversion time was 10±3 7 days and similar in BCG and TST positive and negative cases(p>0 05) Conclusion: BCG vaccination or a positive TST doesn’t have an effect on the susceptibility to and clinical course of COVID-19 in health care workers © 2021 A CARBONE Editore All rights reserved