Immune defences from a common cold may help protect people from Covid-19, according to a small peer-reviewed study from Imperial College London released today.
The study, published in Nature Communications, found people with higher levels of T cells – a type of white blood cell that forms an essential part of the immune system – induced by common cold coronaviruses are less likely to become infected with Covid-19.
Researchers said the findings could provide blueprint for a universal vaccine that could prevent infection from current and future variants including Omicron.
They looked at 52 people who lived with someone who had Covid in September 2020. Of those, 26 people did not become infected with Covid – and they had significantly higher levels of T-cells induced by a common cold coronavirus, compared to the 26 who did catch Covid.
The T-cells target internal proteins within the virus, rather than the spike protein on the surface of the virus. The scientists explained that these internal proteins offer new vaccine targets that could provide long-lasting protection because T-cell responses last longer than antibody responses.
However, the researchers stressed no one should rely on defences from common cold coronaviruses alone and vaccines remain key.
Likewise, Dr Simon Clarke, associate professor in cellular microbiology at the University of Reading, who did not work on the study, warned it would be a ‘grave mistake’ to think anyone who has recently had a cold is protected against Covid-19 as coronaviruses only account for 10-15% of colds.
He added: ‘Similarly, there is no measurement of how much protection the reported effect gives people and a link is only hinted at; it has not been proven conclusively.’
Dr Rhia Kundu, first author of the study, said: ‘While this is an important discovery, it is only one form of protection, and I would stress that no one should rely on this alone. Instead, the best way to protect yourself against Covid-19 is to be fully vaccinated, including getting your booster dose.’
