Catching a cold creates more immune protection against COVID-19

LONDON — Want to protect yourself against COVID-19? A new study suggests catching a common cold. Researchers from Imperial College London say immune cells which activate to fight off common cold coronaviruses have cross-protective powers against the SARS-CoV-2 virus.

The discovery provides a blueprint for a second-generation, universal vaccine that would combat current and future COVID variants, including Omicron. Scientists found cold viruses trigger T cells that reduce the risk of infection.

Researchers examined 52 people exposed to COVID, half of whom eventually tested positive for the illness. Those with more T cells — the body’s immune cells which develop in the bone marrow and fight infections — had previous exposure to other coronaviruses, such as the common cold.

“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,” says first author Dr. Rhia Kundu in a university release.

T cells can fight off COVID longer than normal antibodies

The participants in this study lived with someone with a PCR-confirmed case of COVID. Researchers tested them four and seven days later to determine if they developed an infection. The team also took blood samples to measure pre-existing T cell levels that also cross-recognize COVID proteins.

Results show significantly more T cells among the 26 participants who did not contract COVID-19 compared to the 26 who did. Importantly, the immune cells attack internal proteins within the virus. The findings offer a more effective vaccine target that could provide long-lasting protection.

The researchers explain that T cell responses persist longer than antibodies, which weaken within a few months. Current vaccines only destroy the virus’ spike protein on the surface.

“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,” says senior author Professor Ajit Lalvani.

“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,” Prof. Lalvani continues. “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.”

A smarter and better COVID vaccine?

Designing vaccines able to activate T cells would stop COVID far earlier if they can disable the proteins which cause the virus to replicate. This would be a different approach to vaccine science, offering an additional layer of protection than other jabs.

“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,” Dr. Kundu concludes.

The study is published in the journal Nature Communications.

South West News Service writer Mark Waghorn contributed to this report.

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