The BRACE trial & off-target benefits of vaccines
This week’s expert:
Dr Rama Kandasamy, Paediatrician, Sydney Children’s Hospital; NHMRC Emerging Leader Fellow; Conjoint Lecturer, Infectious Diseases Research, UNSW
Drawn from Dr David Lim’s interview with Dr Rama Kandasamy on the Healthed Podcast, ‘Going Viral’.
• There is evidence, from epidemiological data, that vaccines may have some beneficial off-target effects that is, may confer protection against other diseases beyond the infection targeted by the vaccine
• Specifically, there is evidence that populations who have had BCG and measles vaccination subsequently have fewer hospitalisations for respiratory infections than unvaccinated populations
• BCG vaccination, in particular appears to offer the best overall protection with some research even showing it is associated with fewer recurrences of herpes simplex, in people who vulnerable to outbreaks of cold sores or genital herpes
• It appears BCG vaccination affects the innate immune response, effectively boosting the body’s entire immune system, changing how it responds to antigens.
• It is thought that the off-target benefits associated with the measles vaccine relate more to the fact immunised people don’t get the measles infection, which researchers believe can be associated with a suppression of the immune system for up to two years after the measles infection
• The randomised controlled BRACE trial (BCG vaccination to Reduce the impact of COVID-19 in Australian healthcare workers following Coronavirus Exposure) is currently underway in Australia and aims to determine whether BCG vaccination protects healthcare workers from contracting SARS-CoV-2.
• In addition to investigating whether BCG offers protection against COVID-19, the BRACE trial will also look at whether the vaccination helps protect against other respiratory infections such as flu or RSV
• BCG is a live vaccine and therefore cannot be given to people who are immunosuppressed (inhaled corticosteroid use is not a contraindication for vaccination)
• To date, a few thousand Australian healthcare workers have been recruited into the BRACE trial. Because of Australia’s low numbers of COVID-19 cases the study is being extended into Europe.
• The BRACE trial will run for at least 12 months