Factors determining COVID-19 pneumonia severity in a country with
routine BCG vaccination
Abstract
Background: Bacillus Calmette-Guérin (BCG) vaccination policies of
countries are postulated to have effect on the course of coronavirus
disease 2019 (COVID-19) pandemic. Methods: Retrospective cross-sectional
study was conducted between March 11-June 10, 2020 in a chest clinic in
a state hospital in Istanbul,Turkey. Adults with diagnosis of COVID-19
pneumonia confirmed with severe acute respiratory syndrome coronavirus 2
polymerase chain reaction positivity in a nasopharyngeal sample and
pulmonary infiltrates in computed chest tomography were included
consecutively. Sociodemographic characteristics, body-mass index,
smoking status, comorbid diseases, income rates, and BCG-vaccination
status were compared between severe and mild patients with COVID-19
pneumonia. Results: Study population consisted of 123 adults (mean age,
49.7 years [standard deviation, 13.3 years]; 82 (66.7%) male). The
proportion of BCG-vaccinated cases was significantly lower among severe
patients than mild patients with COVID-19 pneumonia (68.5% vs 88.2%;
p=.026). Mean age (54.0 ± 11.5 years vs 38.3 ±10.7 years; p
<.001), diabetes rate (32.6% vs 5.9%; p=.002) and low-income
(84.3% vs 52.9% p<.001) are higher in patients with severe
COVID-19 pneumonia than in patients with mild COVID-19 pneumonia.
Multivariate logistic regression analysis showed that increasing age
(odds ratio [OR], 1.112; 95% confidence interval [CI], 1.058 –
1.169; p<.001) and low income (OR, 3.369; 95% CI, 1.074 –
10.570; p =.037) are associated with severe COVID-19 pneumonia.
Conclusion: Clinical data does not support that being vaccinated with
BCG is associated with disease severity in COVID-19 pneumonia. Age and
low-income are the major predictors for disease severity.