British scientists unveil new evidence today of how exposure to the common cold may help protect against COVID.
The scientists pinpoint T cells generated by common cold coronaviruses as key to the extra protection.
The study, undertaken at Imperial College, London, is published in *Nature Communications*.
The effect is powerful enough to point the way to a universal vaccine against COVID, according to the researchers.
The findings come from a study of 52 people exposed to COVID infection risk in September 2020. Half of them were infected by the virus.
Analysis of blood samples showed “significantly” greater levels of cross-reactive T-cells, from the common cold, in the 26 who were not infected than in those who were infected.
Researcher Dr Rhia Kundu 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.”
Fellow researcher Professor Ajit Lalvani 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 the virus, rather than the spike protein on its surface. The spike protein is under intense immune pressure from vaccine-induced antibody which drives evolution of vaccine escape mutants.
“In contrast, the internal proteins targeted by the protective T cells we identified mutate much less. Consequently, they are highly conserved between the various SARS-CoV-2 variants, including omicron. 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.”
*Nature Communications* 10 January 2022
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