Can a century-old vaccine for tuberculosis help defeat COVID-19? New research offers some clues

While all eyes have been focused on the race to develop a COVID-19 vaccine, other researchers have been furiously working on another way to defeat the coronavirus. It's a vaccine with a very long track record.

The vaccine was developed more than 100 years ago to fight one of the deadliest diseases known to humanity: tuberculosis. It may now play a crucial role in beating COVID-19.

"It has the capacity to protect you not only against tuberculosis, but against many other viral and bacterial diseases," said Dr. Moshe Arditi, director of Infectious and Immunologic Disorders at Cedars-Sinai.

Scientists observed that the BCG vaccine somehow trains your immune system to, not only to fight the bacteria that causes tuberculosis, but also attack other foreign invaders.

"They get rid of the attacking virus or bacteria, thus giving you a non-specific broad protection against many diseases," he said.

In a new study published in the Journal of Clinical Investigation that used blood samples from 6,000 Southern California healthcare workers, Arditi and his colleagues found that those who had a BCG vaccination were significantly less likely to have COVID-19 antibodies, meaning less of them had been infected.

"Having a history of BCG vaccination among this cohort at our hospital of healthcare workers provided a protection," he added.

The vaccine is not needed here in the U.S., but scientists noticed countries that vaccinated their population against tuberculosis had fewer cases of COVID-19.

The World Health Organization said that was not enough evidence, so large trials began in Europe involving thousands of healthcare workers. Cedars-Sinai is now one of four U.S. medical centers conducting trials here.

This vaccine may also offer a silver lining.

"Potentially, an earlier BCG vaccination may boost the responses to the specific COVID vaccines even higher," Arditi said.

Besides healthcare workers, Cedars-Sinai hopes to also enroll volunteers who are elderly and other vulnerable groups to their trial. Results are expected early next year.