Researchers in a handful of countries are testing a century-old tuberculosis vaccine to see if it can give a boost to the immune system to help it fight off the novel coronavirus now causing the COVID-19 pandemic.
Clinical trials of the Bacille Calmette-Guerin (BCG) vaccine, which was first developed in the early 1920s, are planned in Europe and Australia to see if it can help reduce the prevalence and severity of COVID-19 symptoms, forbes.com reported.
Researchers from the Murdoch Children’s Research Institute (MCRI) in Melbourne are currently working to enroll 4,000 healthcare workers from hospitals around Australia in one study.
“This trial will allow the vaccine’s effectiveness against COVID-19 symptoms to be properly tested, and may help save the lives of our heroic frontline healthcare workers,” MCRI Director Professor Kathryn North said in a release.
A separate large-scale study is planned to include older patients and health care workers at several hospitals in Germany and similar trials are in the works in the Netherlands, the UK and Greece.
This work is very different from the efforts underway to develop a vaccine to confer specific immunity to the novel coronavirus, SARS-CoV2. BCG has a spotty track record giving immunity against even the disease it was developed for, tuberculosis. But as one of few tools available to fight that disease, it has stuck around for decades and a number of studies have shown that it seems to offer other benefits.
“There has been a long history of reports of BCG producing a series of beneficial immune responses,” Gonzalo H. Otazu from New York Institute of Technology’s Department of Biomedical Sciences told me. “For instance, a study in Guinea-Bissau found that children vaccinated with BCG were observed to have a 50 percent reduction in overall mortality, which was attributed to the vaccine’s effect on reducing respiratory infections and sepsis.”
A WHO review in 2014 gave the findings that BCG may reduce overall mortality a very low confidence rating, however. Other reviews have been more favorable.
Still, researchers hope that BCG could be a bridge that suppresses the overall impact of the coronavirus pandemic until a new, targeted vaccine is ready.
Scientists at the Max Planck Institute for Infection Biology developed the vaccine candidate VPM1002 based off of BCG earlier this century, which will be used for the trial starting soon in Germany. VPM1002 has been shown to protect the respiratory tracts of mice from viral infections.
“In addition, VPM1002 can be manufactured using state-of-the-art manufacturing methods which would make millions of doses available in a very short time”, says Adar C. Poonawalla, CEO and Executive Director, Serum Institute of India in a statement.
Otazu has been working with researchers to look at possible correlations between national BCG vaccination policies and the impact of COVID-19 on a country’s population.
“We found that there was a reduction in the number of deaths attributed to COVID-19 per million inhabitants in countries that have universal BCG vaccination (usually at birth) compared to the countries that never established such policy,” he said. “The earlier the establishment of such policy, the stronger the reduction in mortality, consistent with a protection to the elderly population which is more severely affected by COVID-19.”
Italy and the United States, two of the countries hit hardest by the pandemic, do not have universal BCG vaccination policies.
Otazu and his colleagues have produced a paper outlining their findings that is awaiting peer review. He stresses that “although correlations are strong, our study is correlational and does not demonstrate the effectiveness of BCG against COVID-19.”
BCG, if it works at all, may not be able to help everyone touched by COVID-19. It is not recommended for people with compromised immune systems or pregnant women.
