WEDNESDAY, Nov. 25, 2020 (HealthDay News) -- A widely used tuberculosis vaccine may help protect people against the new coronavirus or reduce the severity of COVID-19, a new study suggests.
The Bacillus Calmette-Guérin (BCG) was developed in the early 1900s and is given to more than 100 million children worldwide every year.
In the United States, BCG is approved as a vaccine for people at high risk of contracting tuberculosis (TB) and to treat bladder cancer.
The use of BCG against COVID-19 is being assessed in multiple clinical trials worldwide, and this study suggests it may be effective.
Researchers at Cedars-Sinai in Southern California tested the blood of more than 6,000 health care workers for evidence of antibodies to the new coronavirus. Workers were also asked about their medical and vaccination histories.
The nearly 30% of workers who had previously received BCG vaccinations were much less likely than others to test positive for SARS-CoV-2 blood antibodies or to have had coronavirus infections or symptoms in the past six months, the investigators found.
These differences weren't related to whether workers had received vaccines for meningitis, pneumonia or flu, according to the report published online Nov. 19 in The Journal of Clinical Investigation.
It's not clear why those who had received BCG vaccinations had lower SARS-CoV-2 antibody levels, said study co-senior author Dr. Moshe Arditi, director of Cedars-Sinai's Pediatric and Infectious Diseases and Immunology Division.
"It appears that BCG-vaccinated individuals either may have been less sick and therefore produced fewer anti-SARS-CoV-2 antibodies, or they may have mounted a more efficient cellular immune response against the virus," Arditi said in a Cedars-Sinai news release.
The researchers were interested in studying the BCG vaccine because it has long been known to have a protective effect against a range of bacterial and viral diseases other than TB. Those include neonatal sepsis and respiratory infections, Arditi noted.
While experts don't think BCG would be more effective than a specific vaccine for COVID-19, it could be more quickly approved and made available, he added.
"It is a potentially important bridge that could offer some benefit until we have the most effective and safe COVID-19 vaccines made widely available," Arditi said.
For more on COVID-19 vaccines, go to the U.S. Centers for Disease Control and Prevention.
SOURCE: Cedars-Sinai, news release, Nov. 20, 2020