Had a cold recently? It might make you less likely to catch Covid.
Being infected with the common cold will trigger a T-cell response in the body. T-cells are a type of white blood cell that specialise in tracking down virus-infected cells and killing them.
Now, new research has looked at what happens when a person is exposed to the Covid-19 virus when they already have high levels of pre-existing T-cells in the body due to fighting off other infections, like the common cold.
According to the research, by Imperial College London, those with a higher number of T-cells might be less likely to catch coronavirus.
Researchers said the finding was an important discovery and could help future vaccines give longer-lasting immunity, protecting against variants such as Omicron and Delta.
T-cells are an essential part of the immune system, and this finding could help provide a blueprint for future vaccines.
But, just because it provides some protection, that doesn’t mean it should be relied upon in place of a vaccine.
The scientists warned that “no one should rely on” having a cold alone to protect them against being infected with coronavirus. While it might offer some degree of protection, it’s not as effective as getting inoculated.
Dr Rhia Kundu, from Imperial’s National Heart and Lung Institute, said: “Being exposed to the SARS-CoV-2 virus doesn’t always result in infection, and we’ve been keen to understand why.
“We found that high levels of pre-existing T cells, created by the body when infected with other human coronaviruses like the common cold, can protect against Covid-19 infection.
“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.”
The study was carried out in September 2020, when most people had not been infected with the virus.
It used 52 people who had lived with someone who had contracted the virus. Those 52 people were then monitored to see who would develop the condition.
Blood samples were taken from the respondents within six days of exposure so researchers could analyse the level of pre-existing T-cells induced by the previous common cold infections.
Interestingly, 26 people ended up contracting Covid, while the other half did not.
The latter half had significantly higher levels of T-cells, allowing the scientists to come to the conclusions in the study, which has been peer-reviewed.
Professor Ajit Lalvani, senior author of the study and director of the NIHR Respiratory Infections Health Protection Research Unit at Imperial, said: “Our study provides the clearest evidence to date that T cells induced by common cold coronaviruses play a protective role against SARS-CoV-2 infection.
“These T cells provide protection by attacking proteins within protein the virus, rather than the spike protein on its surface. New vaccines that include these conserved, internal proteins would therefore induce broadly protective T cell responses that should protect against current and future SARS-CoV-2 variants.”
So if you’ve had a common cold, you might have some protection, but the official advice is still to get vaxxed and boosted whenever possible.