Is the tuberculosis vaccine BCG an alternative weapon for developing countries to defeat COVID-19?

Coronavirus disease (COVID-19) is a new respiratory infectious disease, and there is no vaccine currently. Previous studies have found that BCG vaccination can provide extensive protection against respiratory infectious diseases.

Herein, we obtained the latest data from the World Health Organization (WHO) as of August 12, 2020, and determined the relationship between three parameters (including the BCG vaccination coverage, human development index (HDI), and transmission classifications) and the incidence rate and mortality of COVID-19.

The results showed that the morbidity and mortality of COVID-19 in countries with BCG vaccination recommendation were significantly lower than these in countries without BCG vaccination recommendation, and countries with lower HDI have lower morbidity and mortality. In addition, we also found that the mode of virus transmission is also related to the morbidity and mortality of COVID-19.

Although our data supports the hypothesis that BCG vaccination is beneficial in reducing the morbidity and mortality of COVID-19, the data supporting this result may be inaccurate due to many confounders such as PCR testing rate, population characteristics, and protection strategies, the reliability of this result still needs to be verified by clinical trials.