The benefits of the TB vaccine, which boosts the immune system, can be seen in babies more than a year after vaccination, according to a new study published in the journal Science Advances.
The research, led by the Murdoch Children’s Research Institute (MCRI) in Australia, has shown how the BCG vaccine, developed to prevent the risk of tuberculosis, can produce a “trained immune response” that lasts for more than 14 months after administration. of the vaccine. The randomized controlled trial involved 130 infants from the Melbourne Infant Study: BCG for the Prevention of Allergy and Infection (MIS BAIR) and cell plate models to study the immune system response to BCG vaccination. Those vaccinated randomly received the injection 10 days after birth.
Dr. Samantha Bannister, of Murdoch Children, explains that 14 months after receiving the BCG vaccine, reprogramming, a process in which genes are turned on or off, was observed in a specific type of blood cell, called a monocyte.
“The unwanted effects of the BCG vaccine against a series of viruses are explained in part by the reprogramming of the functioning of their genes in the monocyte due to environmental and behavioral factors,” he says. “The reprogramming of monocytes, a cell which until now was considered without memory capacity, leads to a trained immunity”.
Murdoch Children’s Associate Professor Boris Novakovic adds that off-target effects were first identified in Africa, where BCG-vaccinated children had reduced overall mortality rates.
“Off-target effects in Africa were known to last for more than a year, but previous studies looking at BCG-associated monocyte signatures only examined one month and three months after vaccination in adults,” he continued. For the first time we have shown that BCG vaccination can have long-lasting effects on the immune system of babies.”
Novakovic stresses that “since infants are the main population to whom BCG vaccination is administered, this study is important because the findings in adults do not always translate to children.”
For the trial, the research team collaborated with the laboratory of Professor Mihai Netea of Radboud University Medical Center in the Netherlands, who first described trained immunity, and with scientists from the International Trained Immunity Consortium ( INTRIM).
Professor Nigel Curtis, from Murdoch Children’s and the University of Melbourne, says the next step was to see the impact that this early trained immunity had later in childhood and into adulthood.
Professor Curtis’s team at Murdoch Children’s is leading the BRACE trial, the world’s largest examination of the undesirable effects of BCG vaccination in more than 6,800 healthcare workers in Australia, Brazil, Spain, the Netherlands and the UK. The BRACE trial is testing whether the vaccine can protect people exposed to SARS-CoV-2 from developing severe symptoms by boosting their first-line immunity.