Hundreds of South African health workers on Monday were given a century-old tuberculosis vaccine in a trial to see whether the venerable formula can protect against coronavirus.

Devised at France’s legendary Pasteur Institute 100 years ago, the Bacillus Calmette–Guerin (BCG) vaccine is one of the world’s oldest and most trusted immunisations.

“We vaccinated the first participant this morning,” Duncan McDonald, head of business development and marketing at a clinical research organisation called TASK said.

Trials started at Tygerberg hospital in Cape Town, where BCG booster shots were administered to 250 health care workers, while another 250 received a dummy formula, or placebo.