Some are running away from Covid-19 even when surrounded by positive cases... and was it thanks to the common cold?

Some are running away from Covid-19 even when surrounded by positive cases… and was it thanks to the common cold?

Fever, sore throat, and feverish condition: When her 7-and-a-half-year-old son announced his first symptoms a few days ago, Laure immediately took him for an antigen test, which turned out to be positive. In the process, the young woman takes a test. negative returns. But soon I started having headaches and sore throats. And on D+2, my second test was positive. My husband, on the other hand, is nothing. There are no symptoms, and a negative result.”

At home, the small family does not take any particular precautions. “My classmate’s son-in-law caught him, secluded her and her partner in her room for a week, and left her meals outside her door. Everyone does as they feel, but my husband and I never imagined we would ever stop making any kind gesture toward our son. He continued to hug him, and dine with us on “The table. Then we both got our third dose. My husband took another test, still negative, and was surprised he didn’t get infected. He had a cold lately. And with every cold wave, he wondered if it wasn’t Covid-19.”

And if it was precisely these little colds – plus the vaccine – that had such a protective effect? This was stated in a study published this week in the scientific journal Nature Communications by researchers at Imperial College London.

Cellular immunity stimulated by the common cold

“Exposure to SARS-CoV-2 does not always lead to infection, and we wanted to understand why,” says Dr Rhea Kondo, a fellow at the National Heart and Lung Institute at Imperial College London, and lead author of the study. In an interview broadcast by the prestigious university. To find out, the researchers began their work in September 2020, when the UK population was contaminated with little or no vaccination. They selected a sample of 52 people who lived with someone with Covid-19 (confirmed by PCR test), and were therefore exposed to the virus. Each participant performed three PCR tests (on D-Day, on D + 4 and D + 7), to detect any contamination. Result: 26 tests positive, 26 tests negative.

At the same time, blood samples were taken from them (on D-day, D + 7 and D + 28), in order to determine the levels of pre-existing T cells. Those rates were significantly higher in the half who survived the virus. “We have found that high levels of pre-existing T cells, which the body creates when infected with other human coronaviruses such as the common cold, can protect against Covid-19 infection,” Dr. Kondo confirms. It’s clear to the researchers: the cold caught by participants who tested negative for their Covid-19 diet.

A way forward for new vaccines

But for Dr. Kondo, there is no doubt in recommending that people bet on colds to keep COVID-19 at bay. While this is an important discovery, it is only a form of protection, and no one should rely on that alone. She insisted that the best way to protect yourself from Covid-19 is to get a full vaccination and a booster shot.

This discovery could specifically make it possible to develop the second generation of universal vaccines against Covid, which are more effective in protecting against new variants of immune escape, such as the Omicron strain. “Our study provides the clearest evidence to date that T cells caused by cold coronaviruses play a protective role against SARS-CoV-2 infection,” confirms Professor Ajit Lalvani, study co-author and director of the NIHR Respiratory Infection Health Protection Research Unit at Imperial College .

What are the mechanisms by which this immune memory, which is stable in our T lymphocytes after a cold, can lead to the emergence of new protective sera? According to Professor Lalvani, these T cells provide protection by attacking the virus’s internal proteins rather than the spike protein on its surface. Thus, new vaccines including these endogenous proteins will induce a T-cell response, which should protect against current and future variants of SARS-CoV-2.”

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