Common cold T cells protect against COVID, study finds

High levels of protective immune cells that fight some common colds also made people less likely to get COVID-19 in one study.

Researchers found higher levels of T cells against certain colds in people who did not develop COVID while living with someone who had the disease, according to a study published Monday by Imperial College London. The above illnesses were caused by other SARS-CoV-2 related coronaviruses.

The findings, published in the journal Nature Communications, provide further evidence for the protective effects of T cells, an arm of the immune system that is gaining attention as the pandemic reaches its third year and new variants such as omicron weaken protection. of the vaccine.

“Being exposed to the SARS-CoV-2 virus does not always cause an infection, and we wanted to understand why“Said Rhia Kundu, lead author of the study and a researcher at the 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 such as the common cold, can protect”.

UK scientists analyzed blood samples from 52 people living with someone who had tested positive for COVID, of which half were not infected.

This is not the first time that T cells have been cross-checked, and more research is needed to see how this information could help develop better vaccines, said Sam Fazeli, a senior pharmaceutical analyst at Bloomberg Intelligence in London.

Compared to antibodies, T cells tend to survive longer in the body and can kill infected cells, thus preventing serious disease.

They also tend to attack a broader range of related pathogens than antibodies, allowing a greater degree of cross-protection between different viruses or strains, said Peter English, former chairman of the British Medical Association’s committee for public health medicine, in a statement. published by the UK Science Media Center.

Universal vaccine

Antibodies produced by COVID vaccines block the spike protein, which is used by the virus to enter cells. These vaccines tend to lose effectiveness when the spike undergoes significant mutations, as has happened in the omicron variant.

However, T cells produced in response to other coronaviruses target the internal proteins of SARS-CoV-2, according to the scientists. A similar approach could aid the development of a universal vaccine that could prevent infection from current and future variants, the authors said.

“The internal proteins targeted by the protective T cells we identified mutate much less“Said Kundu of the Imperial. “Therefore, new vaccines that include these conserved internal proteins would induce broadly protective T cell responses that should protect against current and future variants. “

There are caveats in 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 remains complete vaccination, including giving a booster dose, Kundu said.