WHILE a coronavirus vaccine is still a way off, some believe we may have a stopgap in the BCG vaccine, which protects against tuberculosis (TB).
In countries with routine BCG vaccination, the pandemic appears to be less severe. This could be due to a long-standing but unproven hypothesis that the vaccine is a general immune-system enhancer.
The Max Planck Institute for Infection Biology in Berlin is planning a clinical trial of a genetically modified version of BCG that has been shown to make mice more resistant to viruses like flu. The trial has regulatory approval and should start this week.
If it succeeds, millions of doses could be made available in a very short time, says Adar Poonawalla at the Serum Institute of India, a private company that is partnering with the Max Planck Institute to develop the vaccine. BCG trials have also begun in the Netherlands and Australia.
Some countries, including the US and Italy, have never had a national BCG programme and others phased theirs out as TB became less of a concern – the UK stopped in 2005.
Gonzalo Otazu at the New York Institute of Technology has found that countries where the BCG vaccine is used have fewer covid-19 cases and/or deaths. He analysed the link using up-to-date information on worldwide BCG programmes.
“The correlation was very clear,” he says. But he cautions that it is too early to recommend action. “BCG vaccination is a potential new tool in the fight against covid-19, but we have to wait for the results of the ongoing clinical trials,” he says.
BCG vaccination is a potential new tool in the fight against covid-19, but we have to wait for trials
Lone Graff Stensballe at the Danish National University Hospital is sceptical, both of the general immune-enhancing claims for BCG and the specific covid-19 idea. “It has not been possible to detect such beneficial non-specific effects of BCG in well-designed studies,” she says. “My advice would be to invest our scarce resources in other preventive measures.