A study of the BCG tuberculosis vaccine discovers immune boosting benefits in infants over a year after vaccination.
Researchers from the Murdoch Children’s Research Institute (MCRI) and published in Science Advances have reported that the BCG tuberculosis vaccine produces a ‘trained immunity response’ lasting over 14 months after the vaccine is administered.
Tuberculosis is a bacterial infection spread through inhaling tiny droplets from the coughs or sneezes of an infected person. Typical symptoms include a persistent cough, weight loss, and night sweats.
Analysing immune system response to the tuberculosis vaccine
The researchers carried out a randomised controlled trial involving 130 infants from the Melbourne Infant Study: BCG for the Prevention of Allergy and Infection (MIS BAIR) and cell dish models to study the immune system response to the BCG tuberculosis vaccine. The individuals who were randomised to be vaccinated received their jab within 10 days of birth.
Murdoch Children’s Dr Samantha Bannister said that 14 months after having the BCG vaccination, they saw reprogramming – a process where genes were switched off or on in a specific blood cell type, called the monocyte.
“The off-target effects of the BCG vaccine against a range of viruses are explained in part by the reprogramming of how your genes work in the monocyte due to environmental and behavioural factors,” she said. The reprogramming of monocytes, a cell previously thought to have no capacity for memory, leads to trained immunity.”
“As babies are the main population given the BCG vaccine, this study is important because findings in adults do not always translate to children.”
Will the vaccine offer immunity into adulthood?
The research team collaborated with the lab of Professor Mihai Netea from the Radboud University Medical Center in the Netherlands that first described trained immunity and scientists from the International Trained Immunity (INTRIM) Consortium.
Murdoch Children’s and University of Melbourne’s Professor Nigel Curtis said the next step was to see what impact this early trained immunity offered later in childhood and into adulthood.
Professor Curtis’ and his team are leading the BRACE trial, which is the world’s largest analysis of the off-target effects of the BCG tuberculosis vaccine in over 6800 healthcare workers in Australia, Brazil, Spain, the Netherlands and the United Kingdom. BRACE aims to understand if the tuberculosis vaccine can protect those exposed to SARS-CoV-2 from developing severe symptoms by boosting their frontline immunity.