Common Cold T Cells May Protect Against COVID-19

Research published in the peer-reviewed journal Nature Communications on January 10, 2022, is one of several recent studies unlocking how previous responses to viruses help shape our future responses to COVID-19.

The disease known as COVID-19 is caused by a family of viruses called coronaviruses, which also cause around 10-15% of common colds.

This new research by researchers with the Imperial College of London suggests that people with higher levels of immune cells – called T cells – caused by infection with common cold coronaviruses ... may be less likely to become infected with SARS-CoV-2, the betacoronavirus that causes COVID-19.

These researchers assess fifty-two COVID-19 household contacts to capture immune responses at the earliest time points after SARS-CoV-2 exposure.

Using a dual cytokine FLISpot assay on peripheral blood mononuclear cells, they enumerate the frequency of T cells specific for the spike, nucleocapsid, membrane, envelope, and ORF1 SARS-CoV-2 epitopes that cross-react with human endemic coronaviruses.

They observe higher frequencies of cross-reactive (p = 0.0139), and nucleocapsid-specific (p = 0.0355) IL-2-secreting memory T cells in contacts who remained PCR-negative despite exposure (n = 26), when compared with those who convert to PCR-positive (n = 26).

There was no significant difference in the frequency of spike responses, hinting at a limited protective function of spike-cross-reactive T cells.

'Our results are thus consistent with pre-existing non-spike cross-reactive memory T cells protecting SARS-CoV-2-naïve contacts from infection, thereby supporting the inclusion of non-spike antigens in second-generation vaccines.'

'Our study suggests that the initial frequency of IL-2-secreting cross-reactive T cells is associated with protection from infection in COVID-19 contacts.'

And, 'our study complements the small but growing body of evidence that T cells may protect against SARS-CoV-2 infection and supports the potential utility of second-generation vaccines targeting core proteins,' stated these researchers.

The study's corresponding author is Rhia Kundu. And the authors declared no competing interests.

Note: Since only a small percentage of common colds are caused by coronaviruses, vaccines are needed to protect people from COVID-19.

“It seems unlikely that everyone who has died or had a more serious [COVID-19] infection, has never had a cold caused by a coronavirus,” said Dr. Simon Clarke, associate professor in cellular microbiology, at the University of Reading, UK, who was not involved in the research.

"Neither do we know how much protection common cold coronaviruses might confer, nor for how long. The only reliable way of ensuring you’re well protected against COVID-19 is to get vaccinated against it," reported GAVI on January 14, 2022.