Vaccine for TB offers hope in pandemic fight

Trials set up to study anti-tuberculosis tool's effect on COVID-19 amid fresh waves in Europe

With the resurgence of COVID-19 in Europe, many healthcare professionals are expanding their search for therapies to fight the pandemic-including one vaccine made a century ago against a different enemy.

The Bacillus Calmette-Guerin or BCG vaccine was developed during one of the world's big outbreaks-the Spanish flu pandemic from 1918 to 1920. The vaccine was not created to fight that particular disease but to take on bacterial respiratory infection tuberculosis, another great medical challenge then.

BCG has since been administered millions of times throughout the decades all over the world and, in addition to helping overcome tuberculosis in many regions, has been observed to have other medical benefits that derive from its ability to stimulate the immune system.

Many scientists are now hoping BCG may also be able to subdue the novel coronavirus, with major trials set up. If the vaccine offers some protection against COVID-19, such as a diminished chance of catching the coronavirus, or the prospect of having milder symptoms, the readily available vaccine could offer breathing space while a dedicated vaccine is found, tested and mass produced.

The aim is to offer BCG first to healthcare workers to ensure they stay strong enough to remain at work, according to researchers.

"People on the COVID-19 front line, including healthcare workers and care home workers, are particularly vulnerable to coronavirus infection," said John Campbell, a professor at the University of Exeter Medical School and the United Kingdom's leading researcher in the international trials. "Up until now, care home workers have been overlooked by most research."

Campbell said the international study into the effectiveness of BCG will involve 10,000 healthcare workers from around the globe. Some will be given the BCG vaccine while others will be given a placebo.

The trial follows Tedros Adhanom Ghebreyesus, the director-general of the World Health Organization, writing to medical journal The Lancet in May with three senior healthcare professionals to point out that "BCG might have a role in protecting healthcare workers and other vulnerable individuals against severe coronavirus disease 2019".

The interest in the 100-year-old vaccine follows clinical trials in the past that have suggested it works well at mitigating respiratory infections. One such trial found that BCG reduced deaths by 38 percent in newborn children in Guinea-Bissau because it slashed the number of pneumonia and sepsis cases.

The latest edition of healthcare magazine Nursing Times reported that 2,000 community nurses and care home workers are being recruited to take part in the UK branch of the trials, which began in April in other parts of the world.

The study is being coordinated by the Murdoch Children's Research Institute in Melbourne, Australia, while the UK portion is being overseen by the Exeter Clinical Trials Unit.

Healthcare workers in Brazil, the Netherlands and Spain are also taking part.

The study hopes to mainly enroll healthcare workers based in care homes and clinics but will include caterers and administration staff working in medical practices and hospitals, according to The Guardian newspaper. The researchers will monitor those given the jab to see whether they get fewer infections or have less severe illnesses. They hope to have an idea of whether BCG, which is available in vast stocks of the vaccine on pharmacy shelves, is effective in a matter of months.

Campbell said an international team of scientists published results in scientific journal Cell last month of a study that showed elderly people who had been given the vaccine developed significantly fewer infections.

"If we see anything close to that sort of protection for coronavirus, this could be a global game-changer," he said.

The vaccine works on things other than tuberculosis because, while its primary goal is to stimulate the adaptive immune system to target TB by unleashing antibodies and T-cells, it also boosts the "innate "immune system. That first line of defense is faster but less targeted and tries to defeat any invading infection.

It just remains to be seen whether novel coronavirus is among those infections it is adept at seeing off.

Mihai Netea, a researcher at Radboud University in the Netherlands, told The Guardian: "We think that in a non-vaccinated person, the virus comes in and starts to multiply, but the host defenses are slow, so the virus has a chance to multiply a lot. With BCG, we want to strengthen that initial response, to make the immune system fight hard and fight early, so the virus does not have a chance to multiply."

If the vaccine works on COVID-19, it could work on other future pandemics, offering the prospect of a product that is capable of buying time while a specific, targeted vaccine is found, Reuters reported.