Infection from common colds can help protect against COVID-19
People who have already been infected by some common cold viruses are less likely to get COVID-19, a new NIHR-funded study has found.
Some common colds are caused by coronaviruses, which the immune system learns to recognise using T cells. New findings from the INSTINCT study, published in Nature Communications, shows people with higher levels of these coronavirus-specific T cells are less likely to become infected with SARS-CoV-2, the coronavirus that causes COVID.
The study began in September 2020, when few people had immunity against COVID, and assessed the proportion of household contacts who also developed the infection.
In total, 52 participants, including two from Oxfordshire and one from Buckinghamshire, did PCR tests at the outset and four and seven days later. Half developed COVID and half did not.
All lived with someone diagnosed with COVID.
Researchers analysed blood samples to measure levels of pre-existing T cells from previous coronavirus common colds and found those who didn’t develop COVID had significantly higher levels of these T cells than those who did become infected.
These T cells target internal proteins within the COVID virus to protect against infection. These proteins are less likely to change over time compared to surface proteins, which are targeted by existing vaccines.
It is therefore hoped findings can help develop a universal vaccine to prevent infection from current and future COVID variants, including Omicron.
Professor Ajit Lalvani, senior author of the study, 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 antibodies 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.”
Read more on the NIHR website.