Some Covid-19 vaccines may protect people from infections other than Covid, by inducing a phenomenon known as "trained immunity" in people after their first dose, according to new research.
Researchers at Trinity College Dublin examined the impact on people who had been given the AstraZeneca vaccine and found that when they were exposed to different bacteria, they had a better immune response than normal.
Lead author of the research Dr Sharee Basdeo, who is Assistant Professor in Clinical Medicine at TCD, said a blood test was taken from people before they received the vaccine, then two weeks, two months, and three months post their first injection.
Speaking on RTÉ's Morning Ireland, she said they observed the innate part of the immune response, as opposed to the antibody responses and T-cell response.
The AztraZeneca vaccine was able to boost and promote innate immune responses in people for up to three months after their first vaccination, she said.
Dr Basdeo said these responses will give protection against unrelated infections, such as bacterial infection that are not Covid-19 and the evidence suggests that definitely up to two months, and as much as three months protection was achieved.
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She said the research shows that the innate response cells, which were believed to have no memory capacity, can be reprogrammed and trained in response to the AstraZeneca vaccine, for example.
They are able to then have a boosted heightened immune response against anything they encounter next.
Dr Basdeo said there is lots of evidence to suggest that live vaccines can protect against other infections that they were not designed to protect against, such as the BCG vaccine, which can induce non-specific protective effects.
"We're very excited about this work, because obviously there's still lots of unknowns around what we've discovered, but really, what this means is going forward that we might be able to use the adenovirus vector platform as an interim response for an emerging infection", Dr Basdeo said.
This would mean people could get two or three months of protection while a very specific vaccine is developed.
"It also means that it could have therapeutic potential for somebody that might be at high risk of secondary infections, for example, we would be able to kind of boost and bolster innate immune function in people."
The research was funded by the Health Research Board and Science Foundation Ireland and published in the Journal of Clinical Investigation.
