BCG, tuberculosis vaccine, being tested for use against COVID-19

Is there any relationship between the low number of cases of COVID-19 in sub-Sahara African countries and the sustenance of Bacille Calmette-Guerin (BCG) vaccination as part of their national immunisation programmes?

Researchers in Europe and Australia are examining whether BCG, a tuberculosis vaccine, can be an effective boost to the immune system to help it fight off the novel coronavirus.

A report by Forbes’ Eric Mack said that clinical trials of the 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.

In Nigeria, BCG vaccination is part of the National Programme on Immunization (NPI), and it is given within the first week of the life of babies. There are similar programmes in other African countries.

Italy and the United States, two of the countries hit hardest by the pandemic, do not have universal BCG vaccination policies.

According to the Forbes report, researchers from the Murdoch Children’s Research Institute (MCRI) in Melbourne, Australia, are currently working to enrol 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.

“There has been a long history of reports of BCG producing a series of beneficial immune responses,” Dr Gonzalo Otazu from New York Institute of Technology, College of Osteopathic Medicine, told Forbes. “For instance, a study in Guinea-Bissau found that children vaccinated with BCG were observed to have a 50 per cent reduction in overall mortality, which was attributed to the vaccine’s effect on reducing respiratory infections and sepsis.”

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 the 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.

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 favourable.

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.

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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.”

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, said Forbes, may not be able to help everyone touched by COVID-19. It is not recommended for people with compromised immune systems or pregnant women.


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