Concerns for the welfare of frontline medical workers have also been intensified by widespread shortages of personal protective equipment such as masks, gowns and gloves, with some doctors and nurses told to reuse some gear to protect dwindling stocks. Loading While the BCG vaccine does not protect against the virus, research suggests it has the ability to train the immune system to respond more strongly to new infections, fight off respiratory disease and hopefully reduce the severity of COVID-19 symptoms. Extreme and frequent exposure to those infected by COVID-19 means medical staff are at far greater risk of contracting the virus, with thousands of healthcare workers already infected around the world. "The vaccine has remarkable properties and it does a lot more than just protect against tuberculosis," Professor Nigel Curtis, group leader of infectious diseases at the Murdoch Children's Research Institute, said.

"It has previously unrecognised effects on the immune system which can actually boost it and enable it to protect against numerous different infections." Loading The vaccine activates our innate immunity, which in human evolution is our body's first defence against new bacteria or viruses and causes it to respond faster to fight off disease. "You might ask, why do we think this useful for COVID-19 disease?" Professor Curtis said. "Well, the reason for this is because a number of studies have already shown individuals who had this vaccine have much less viral respiratory tract infections than those who don't."

Other studies have shown that people who have had the BCG vaccination and subsequently contract a virus have less virus levels in their blood than those who haven't had the vaccine. A World Health Organisation-approved study starting next week will recruit 4000 medical workers in hospitals across Australia, half of whomwill be given BCG. Loading Replay Replay video Play video Play video The health outcomes of vaccinated medical workers will be compared with those of their colleagues who do not receive the vaccine. The workers will be monitored via an app set up by researchers to track them for six months. "We will monitor them for COVID-19 and more importantly, the severity of disease they suffer if they do become infected," Professor Curtis said.

During the deadly SARS coronavirus epidemic in 2003 about 20 per cent of those infected globally were healthcare workers. "Healthcare workers are at very high risk and there have already been numerous deaths of healthcare workers across the world," Professor Curtis said. "This has major implications because what we have seen in China, Italy and Spain is that large numbers of the workforce become unwell with COVID-19 or have to go into quarantine and that makes it even more difficult for hospitals to cope with the surge of patients." Professor Curtis said because BCG has been around for 100 years it is known to have very few side-effects or medical risks. The most significant is a small scar on the upper arm from where the vaccine enters the body.

The vaccine would not hinder the benefits of other anti-viral medications being trialled to combat COVID-19, he said. Looking for some good news? We could all do with some good news right about now. That’s why we have launched The Good News Group, a Facebook group where we’ll share uplifting, inspiring and positive stories and invite members to do the same. Join the group here. Similar trials are also being undertaken among medics in the Netherlands, Germany and the UK. University of NSW senior medical virologist Professor Bill Rawlinson said it was important to note BCG was not an anti-viral medication, but rather a vaccine able to boost the immune system, and should be used alongside other preventive measures. "The idea is you boost general immunity to fight infection, so it's not specific for COVID-19," Professor Rawlinson said. "However, it's a really great idea to trial alongside things like new anti-viral medications and very important public health interventions that help prevent the spread."

Healthcare workers taking medications which may interfere with the vaccine or who have underlying medical conditions will be omitted from the BCG trial. Researchers at Melbourne's Walter and Eliza Hall Institute of Medical Research are also testing the use of hydroxychloroquine, an anti-malarial drug, in a world-first trial aimed at protecting healthcare workers from contracting coronavirus when exposed to it. Sign up to our Coronavirus Update newsletter Get our Coronavirus Update newsletter for the day's crucial developments at a glance, the numbers you need to know and what our readers are saying. Sign up to The Sydney Morning Herald's newsletter here and The Age's here. People can have the BCG vaccine more than once in their life without risk. Doing so would boost the immune system further. As TB has been eradicated in Australia, the vaccine is not widely available here. But if researchers find it works to reduce the risk of COVID-19 they want to roll it out for use among vulnerable groups like the elderly.