In the worldwide battle against Covid-19, scientists are investigating whether a century-old tuberculosis vaccine might offer some additional protection against the novel coronavirus, according to AFP.

Bacillus Calmette-Guerin (BCG) was developed by two French researchers, Albert Calmette and Camille Guerin, in 1921 as a vaccine against tuberculosis.

The WHO, for its part, said last month that there is no evidence that BCG protects people against infection with Covid-19.

Nevertheless, Bulgarian scientists suggest that the Balkan country's high rate of BCG vaccination — as well as an early lockdown — helped it to escape the worst of the pandemic.

“BCG generates a powerful immune stimulation. And while we are waiting for a specific treatment or vaccine against the novel coronavirus, we must put our bets on immunity,” immunology professor Bogdan Petrunov told BNT public television.