Relationship between BCG Vaccine Injection with Frequency and Severity of COVID-19 Disease

Bacillus Calmette-Guérin (BCG) vaccine endows non-specific immunity against other respiratory tract infections (RTIs) such as Coronavirus. According to the lack of sufficient evidence in this field, the present study was to determine the correlation between BCG vaccination with frequency and the severity of the pandemic in Iran. This was a cross-sectional study. The study participants were comprised of all hospitalized patients with suspected coronavirus disease (COVID-19) in selected military hospitals in Tehran. Convenience sampling was also operated with regard to the inclusion criterion in the study. The data collection tool was a demographic-clinical information form. Also, checking the vaccination scar on the upper arm, interviewing, and asking patients or their companions to self-report the history of vaccination were the techniques to confirm BCG vaccination in the patients. The data were analyzed using the IBM SPSS Statistics (v.22.0) software package. In this study, 400 patients completed the questionnaires. The results of this study showed that most of the patients were male. The mean age of the participants was 52.35±6.98 years. The majority of the participants were infected with COVID-19 and other underlying diseases. The test results showed no significant relationship between the history of BCG vaccination and COVID-19 infection, but a significant correlation was detected between BCG vaccination and the disease severity (P=0.015). The test results also showed a significant relationship between age and COVID-19 severity (P=0.034). A significant relationship was further spotted between the COVID-19 severity and the history of underlying diseases (P=0.031). Considering that BCG vaccine is one of the most common strategies applied across the world; it was suggested to use it to prevent severe types of respiratory tract infections. Future studies should be conducted on different types of human populations such as children and pregnant women.