By Graham Lawton
Mark Thomas/Alamy
As researchers race to make a new vaccine against covid-19, some are touting a century-old one as a possible substitute.
The vaccine is BCG (Baccillus Calmette-Guérin), which protects versus tuberculosis (TB). In countries with routine BCG vaccination, the pandemic seems less extreme. Supporters of BCG state this might be because the vaccine is a general immune-system enhancer– an enduring however unproven hypothesis. However critics state we can’t make sure.
BCG has been used given that1921 It consists of a live germs related to the one that triggers TB, …
