Catching the common cold can help fend off Covid, study finds

People with high levels of protective immune cells (T cells) from common colds are less likely to to contract Covid-19, according to a study published in the journal 'Nature Communications' says.

Researchers said the findings could help provide the blueprint for the production of new vaccines which give longer-lasting immunity and would protect against current and future coronavirus variants such as Omicron and Delta., according to a study released Monday by the UK's Imperial College London. 

Imperial College London researchers say the high levels of T cells and the role in fighting Covid is an "important discovery" - but warned "no one should rely on this alone" and insisted people should still get vaccinated as the "best way" to protect against Covid.

T cells are a type of white blood cell that help protect the body from infection.

"Being exposed to the SARS-CoV-2 virus doesn't always result in infection, and we've been keen to understand why," said Rhia Kundu, the study's lead author and a researcher at Imperial's National Heart and Lung Institute. "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." 

The UK scientists analyzed blood samples from 52 people who lived with someone who had tested positive for Covid, of which half didn't become infected. Their conclusions show the protective role of T cells induced by other coronaviruses for the first time, they said. 

Compared with antibodies, T cells tend to survive longer in the body and can kill infected cells, preventing serious illness. They also tend to attack a wider range of related pathogens than antibodies, which allows for a greater degree of cross-protection across different viruses or strains, Peter English, former chair of the British Medical Association's public health medicine committee, said in remarks published by the UK's Science Media Centre.

'No one should rely on this alone'

Dr Rhia Kundu, first author of the study, from Imperial's National Heart & Lung Institute, said: "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.

There are caveats to the findings. The study was small and 88% of the participants were of white European ethnicity, according to the statement. The best way for people to protect themselves against Covid is still to be fully vaccinated, including getting a booster dose, Kundu said.