Factors determining COVID‐19 pneumonia severity in a country with routine BCG vaccination

Aksu, Kurtuluş; Naziroğlu, Tuğba; Özkan, Pınar

BACKGROUND: The impact of countries' Bacillus Calmette‐Guérin (BCG) vaccination policies on the course of coronavirus disease (COVID‐19) outbreak is a curiosity. In this study, the relationship between BCG vaccination status and severity of COVID‐19 pneumonia and the factors affecting disease severity were investigated. METHODS: A retrospective cross‐sectional study was conducted between March‐June 2020 in patients diagnosed with COVID‐19 pneumonia, confirmed by severe acute respiratory syndrome coronavirus‐2 polymerase chain reaction positivity in a nasopharyngeal sample and pulmonary infiltrates in computed chest tomography, in a state hospital in Istanbul, Turkey. Sociodemographic features, body mass index, smoking status, concomitant diseases, income rates, and BCG vaccination status of subjects were analyzed. RESULTS: Study population consisted of 123 adults with COVID‐19 pneumonia (mean age, 49.7 years [standard deviation, 13.3 years]; 82 (66.7%) male). While the rate of cases vaccinated with BCG is lower (68.5% vs 88.2%; p=.026), the mean age (54.0 ± 11.5 years vs 38.3 ±10.7 years; p <.001), diabetes (32.6% vs 5.9%; p=.002) and low income (84.3% vs 52.9% p<.001) are higher in patients with severe disease compared to those with mild disease. According to multivariate analysis increasing age (odds ratio [OR], 1.119; 95% confidence interval [CI], 1.062 – 1.178; p<.001) and low income (OR, 3.209; 95% CI, 1.008 – 10.222; p =.049) are associated with severe disease in COVID‐19 pneumonia. CONCLUSION: This study reveals that BCG vaccination is not associated with disease severity in COVID‐19 pneumonia. Age and low income are the main determinants of severe COVID‐19 pneumonia.