A new study has found that countries that use the Bacillus Calmette-Guerin (BCG) or tuberculosis vaccine have lower coronavirus death rates than countries that don’t. Despite that, the World Health Organization (WHO) said it would not recommend the BCG vaccination for the prevention of COVID-19.

Based on a study conducted by researchers at the Johns Hopkins Bloomberg School of Public Health, there is a direct association between the use of the BCG vaccine and lower mortality rate in countries affected by the COVID-19 pandemic. According to researchers, the COVID-19 mortality rate in countries that use the vaccine is 5.8 times lower than those that don’t.

“Demonstration that exposure to BCG vaccination can ameliorate severe COVID-19 disease and lower mortality could rationalize a therapeutic or preventive strategy that can have immediately deployable global impact,” the researchers wrote.

The aim of the study was to examine at the ecological level whether the inclusion of BCG in national immunization schedules was associated with country-level COVID-19 mortality. Based on the mortality per 1 million residents of each country, the researchers were able to assess the fatality rate of the 50 countries with the highest coronavirus cases in the world.

While the researchers found that lower COVID-19 mortality rates in some countries were attributable to BCG use, they said the findings still “warrant deeper epidemiological scrutiny and prospective evaluation in individually randomized trials.”

“I think BCG vaccine is a bit of the equivalent of a Hail Mary pass. It’s such an outside-the-box concept that one would like to be optimistic, but we’ll have to wait and see,” said infectious disease specialist Dr. William Schaffner.

Two clinical trials addressing the question of whether or not the BCG vaccine can protect people against the novel coronavirus are still underway. After the tests, the WHO will evaluate the evidence to confirm the vaccine’s efficacy in protecting people against the novel coronavirus.  As long as evidence remains unavailable, the WHO will not recommend BCG vaccination for the prevention of COVID-19.

The BCG vaccine was first administered to humans in 1921 as a protection against tuberculosis. Although the WHO does not recommend BCG for the prevention of COVID-19, the organization continues to recommend neonatal BCG vaccination in countries with a high incidence of tuberculosis.

Coronavirus COVID-19 Test Kit A medical staff displays a test kit to detect the novel coronavirus at a COVID-19 screening-drive, at the Amsterdam UMC in Amsterdam The Netherlands, on March 24, 2020. ROBIN VAN LONKHUIJSEN/ANP/AFP via Getty Images