Coronavirus: Why some of us don't catch COVID
“No COVID” or “never COVID” people have never been infected with coronavirus
There are many among us, who have not been infected by the coronavirus despite living within the same environment and under the same condition. So what makes these people "invincible" against the contagious coronavirus despite being exposed to it? Often called the “no COVID” or “never COVID” people, these individuals not just save themselves from the viral attack, in a way they also help to cut down the transmission of the virus.
Who are the no-COVID people?
These are those who have been lucky up to this point by not getting infected with the coronavirus which has till date infected 440,807,756 people worldwide.
COVID caused by the coronavirus was first detected in November 2019 in the Wuhan region of China. Few months later it was declared a global pandemic by the World Health Organisation (WHO). Since then the entire world has been within the tight grip of COVID infection which is coming in different waves with different symptoms and severities.
So far 5 mutated variants of the coronavirus have been categorised by the WHO as variants of concern.
To cut down the risk of COVID governments worldwide are imposing lockdowns at local levels. In these two years people have conditioned themselves to stay away from the virus by keeping themselves indoor, working from home and minimising travel.
But there is a section of people among us, who despite living in the same environment where the others have been exposed to the virus, have not contracted the infection.
What accounts for their invincibility?
A study by the Imperial College London has said that there are several people who have higher levels of T cells, a type of memory cell in the immune system, developed from other common cold coronaviruses; and these people show immunity against the current coronavirus which is causing the COVID.
“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,” Dr. Rhia Kundu, first author of the study, told CNBC.
There are a number of coronaviruses, many of which are linked with common colds. As per the study though all coronaviruses behave differently, there are certain characteristics where they are similar to each other. It may be because of this similarity the immune cells are able to recognise them and fight off the virus as soon as the body is exposed to it which is why the individual does not get COVID.
No COVID people vs. asymptomatic individuals
We all know that asymptomatic individuals are those who do not show any symptoms but are equally responsible for the transmission of the virus just like the infected individuals.
No-COVID people are those who do not have the infection or the virus within them. These individuals have an immunity system which is way too protective against the virus. Since they do not have the virus within them, it is likely that they do not spread the disease.
Is it immunity or no testing?
This can spark a debate. We all know how skewed COVID testing has been. Under-testing has been a concern for health experts and scientists and is said to be hindering research studies on the infection.
Under-testing can be a serious concern because so far it has been the only way to distinguish between symptomatic and asymptomatic individuals. Many asymptomatic individuals skip testing because they do not show the disease, due to which they might be seeing themselves as “someone with strong immunity” but in fact they contribute to spreading the infection as much as the infected ones.
What do the genes say?
Genetic factors play a role in determining the susceptibility of an individual to COVID. Studies have found that the relationship between genetics and the immune system and COVID-19 infection is also crucial to understand.
Researchers have said that the behaviour of human leukocyte antigens determine one's response to COVID. “The key genes that control your immune response are called human leukocyte antigen or the HLA genes. They matter for determining your response on encounter with SARS-CoV-2. For example, people with the gene HLA-DRB1*1302 are significantly more likely to have symptomatic infection,” Danny Altmann, professor of immunology at Imperial College London told the media.
Is it necessary for these people to get vaccinated?
What if you just have been lucky till this point. The possibility of remaining free of the virus in the future can be ruled out in view of the emerging variants and new infectious waves.
So far, vaccination is only the most effective armour against the virus. It might be because of vaccination, the Omicron variant of coronavirus could not affect human beings seriously.
In order to safeguard against viruses, one definitely needs to be vaccinated. Not just vaccination, one should also get timely precaution dose or booster shots.
What is the role of vaccines?
Is it possible that these "no COVID" people didn't get the infection during the first wave and due to early vaccination their body developed an immunity that is hard for the virus to invade? It can be a possibility.
Scientists and health experts vouch for the effectiveness of COVID vaccine. Less severity and low hospitalisations seen during the Omicron wave were attributed to worldwide vaccination programs.
To explain the possible reason behind why many do not get COVID, experts have said that cross reactive immunity and vaccines benefit these individuals. “Certainly cross-reactive immunity from previous infections with common cold coronavirus is likely to be a major contributor, particularly as these individuals may have additional immune benefits from also having been vaccinated," Lawrence Young, a professor of molecular oncology at Warwick University told the media.