Home'Never COVID cohorts': Why some people get COVID-19 when others don’t

'Never COVID cohorts': Why some people get COVID-19 when others don’t

Researchers across the world have dedicated themselves to the study of so-called never Covid cohorts, who have been exposed to infected people, but are themselves resistant to the infection.

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By CNBCTV18.com February 6, 2022, 8:52:39 AM IST (Updated)

'Never COVID cohorts': Why some people get COVID-19 when others don’t

Being exposed to the COVID-19 does not always result in an infection, say infectious disease specialists who are investigating the mystery of why some people catch COVID-19 and others don’t.



Researchers across the world have dedicated themselves to the study of the so-called never COVID cohorts, who have been exposed to infected people, but are resistant to the infection.


Data suggests these so-called ‘never Covid’ individuals have naturally acquired immunity from previous infections with common cold coronaviruses, Lawrence Young, professor of molecular oncology at Warwick University, told CNBC.


Higher levels of T-Cells


Last month, research revealed that people with high levels of protective immune cells that fight common colds were less likely to contract SARS-CoV-2, the virus that causes COVID-19.


Researchers at UK’s Imperial College London detected higher levels of T-cells, a type of cell in the immune system from common cold, in people who lived with those who contracted the COVID-19 infection, Bloomberg had reported last month.







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“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,” Rhia Kundu, first author of the study from Imperial’s National Heart and Lung Institute, said in the findings, published in the journal, Nature Communications.


However, Kunda added that it is only one form of protection and the best way to stay safe was to get fully vaccinated, including the booster dose.


Vaccine status


COVID vaccination status is also one of the factors that make one more susceptible to the infection than others.


COVID vaccines have been proven to remain effective against known variants and reduce severe infections, hospitalisations and deaths. However, the immunity they provide wanes over time.







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Many people caught the Omicron variant of the infection despite being fully vaccinated. However, vaccines reduce the chance of being infected by the Omicron variant, although responses differ from one person to another, Andrew Freedman, an academic in infectious diseases at Cardiff University Medical School, told CNBC. “So, some people catch it and others don’t despite very significant exposure,” he said.


Abortive infection


In November last year, a group of researchers at University College London had found that some people also experience “abortive infection” in which the T-cells clear the virus when it enters the body at the earliest stage, showing negative results in PCR and antibody tests.


The study tracked healthcare workers during the first wave of the pandemic in London and found that around 15 percent appeared to fit the scenario, The Guardian had reported.


Further studies into so-called never COVID cohorts is likely to help in not just developing a better understanding of the immune response to the infection, but also pave the way for a new generation of vaccines with much longer lasting immunity.


Also read: Joe Biden sees US economy as powering past COVID-19 pandemic
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