Could BCG vaccine protect against COVID-19?

A largescale global trial designed to test the theory that the widely-used BCG vaccine could help protect against COVID-19 will soon recruit healthcare staff and care home workers in the UK.

The University of Exeter is leading the UK arm of the trial, called the ‘BCG vaccination to Reduce the impact of COVID-19 in healthcare workers’ (BRACE) Trial.

The BRACE trial is coordinated by the Murdoch Children’s Research Institute (MCRI) in Melbourne, Australia. The trial has received more than $10M from the Bill and Melinda Gates Foundation to allow its global expansion. The Peter Sowerby Foundation has contributed funding to support the Exeter trial site.

The UK joins study centres in Australia, the Netherlands, Spain, and Brazil in the largest trial of its kind. Together, the trial will recruit more than 10,000 healthcare staff. Participants will be given either the BCG vaccine (currently given to more than 100 million babies worldwide each year to protect against tuberculosis (TB)) or a placebo injection. In the UK, routine BCG vaccination was stopped in 2005 because of low rates of TB in the general population.

Professor John Campbell, of the University of Exeter Medical School, is the UK lead on the BRACE study. He said: “COVID-19 has killed more than a million people globally, with well over 33 million people acquiring the disease, sometimes in its severest forms. BCG has been shown to boost immunity in a generalised way, which may offer some protection against COVID-19. We’re excited to be contributing to the large-scale, international BRACE study where we are seeking to establish whether the BCG vaccine could help protect people who are at risk of COVID-19. If it does, we could save lives by administering or topping up this readily available and cost-effective vaccination.”

Previous studies suggest that the Bacillus Calmette-Guerin (BCG) vaccine could reduce susceptibility to a range of infections caused by viruses including those similar to the novel coronavirus causing COVID-19. Examining the mechanism by which this may work is part of the trial being conducted by BRACE researchers.

The BCG vaccine boosts immunity by ‘training’ the immune system to respond to other subsequent infections with greater intensity.

Researchers hope this improved ‘innate immunity’ will buy crucial time to develop an effective and safe vaccine against COVID-19.

The BRACE trial is initially recruiting care and healthcare workers in the South West of England, who can attend clinics in Exeter. The trial is targeting these professionals because they work in fields with high exposure to COVID-19. The trial is specifically looking at whether the BCG vaccine reduces coronavirus infection or COVID-19 symptom severity.

Professor Campbell added: “People on the COVID-19 front line, including healthcare workers and care home workers, are particularly vulnerable to coronavirus infection. Up until now, care home workers have been overlooked by most research. The BRACE trial provides us with a great opportunity to offer potential help to this important group of individuals who are providing healthcare to some of our most vulnerable citizens in important community settings. I’d really encourage care-home staff to join us, to help us find out if the BCG vaccine might provide a safe, widely available and cost-effective way to reduce the risk of COVID-19.”

In the UK, the trial will be conducted by the Exeter Clinical Trials Unit and supported by the local National Institute for Health Research funded Clinical Research Facility. Lynne Quinn, Operations Director of Exeter CTU, said the trial is initially seeking to recruit 1,000 participants who work in care homes and other community healthcare settings. She said: “The first wave of recruitment will take place in and around Exeter, and we have exciting plans to expand to other sites across the UK, so we hope to be expanding our recruitment numbers at a later stage.”

Professor Nigel Curtis, global lead of the BRACE trial at MCRI, said: “We are delighted that the UK is joining this international trial to help determine if we can repurpose an existing safe vaccine to reduce the impact of COVID-19 in healthcare workers, including those working in care homes who are at particular risk.”

Participants will be asked to complete a daily symptom diary via an app, be tested for COVID-19 whenever they have symptoms, complete regular questionnaires and provide blood samples. These samples will allow scientists to understand how blood cells respond differently to exposure to COVID-19 and other viruses, with and without the BCG vaccine.

To find out more or to take part, visit https://www.exeter.ac.uk/brace