'T-cells from common colds may help fight virus'

People with higher levels of T-cells from common cold coronaviruses are less likely to become infected with SARS-CoV-2, according to new research. The study, by Imperial College London researchers, provides the first evidence of a protective role for these T-cells.

While previous studies have shown that T-cells induced by other coronaviruses can recognise SARS-CoV-2, the new study, published in Nature Communications, examines for the first time how the presence of these T-cells at the time of SARS-CoV-2 exposure influences whether someone becomes infected.

The researchers also stated their findings provide a blueprint for a second-generation, universal vaccine that could prevent infection from current and future SARS-CoV-2 variants, including Omicron.

"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," said Dr Rhia Kundu, from Imperial's National Heart and Lung Institute.

"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," she added.

The study included 52 people who lived with someone with PCR-confirmed SARS-CoV-2 infection and who had therefore been exposed to the virus. The participants did PCR tests at the outset and 4 and 7 days later, to determine if they developed an infection.