Your family had it, your friends called you one day with the dreaded result, the colleagues at work had it too, and perhaps even you at one point of time managed to contract the COVID 19 virus, but there is that one person you know who no matter what wave or variant or month or phase, they just managed to evade the virus. Lucky? Maybe. But besides luck scientists are now trying to decipher how this is entirely possible.
Is the amount of exposure to the COVID 19 virus a determining factor?
One would argue that perhaps the people who have evaded the virus until now are those who haven't been exposed to it and have been holed up or quarantined and isolated from others. However, scientists were ahead of this. In order to determine if exposure actually did play a role in a person’s ability to catch the virus, the world’s first COVID 19 challenge trial was conducted.
As part of this, the live Coronavirus was dripped into the noses of the participants and this was followed by pegging their noses shut, in order to allow the virus to have its full effect. Phoebe Garrett was one of the participants.
“We had multiple rounds of tests, and different methods of testing: throat swabs, nose swabs, other types of swabs that I’d never done before like nasal wicks – where you hold a swab in your nose for a minute – as well as blood tests, but I never developed symptoms, never tested positive,” Garrett said in an article to The Guardian. “My mum has always said that our family never gets flu, and I’ve wondered if there’s maybe something behind that.”
Garrett did not become infected after the trial as did many others, offering something in the way of proof that some people really are immune to the virus. Of the 34 participants who were exposed to the virus, 16 did not develop any infection.
Why do some people not get infected with COVID 19?
The study suggests that the reason why people do not get infected may be because of an early immune response. Prof Christopher Chiu at Imperial College London, who led the study says that “In our previous studies with other viruses, we have seen early immune responses in the nose that are associated with resisting infection. Together, these findings imply that there is a struggle between the virus and host, which in our ‘uninfected’ participants results in prevention of infection taking off.”
“The levels of the virus didn’t climb high enough to trigger detectable levels of antibodies, T cells or inflammatory factors in the blood that are usually associated with symptoms,” Chiu said referring to participants of the study who experienced mild symptoms.
This essentially means that when people are exposed to the COVID 19 virus before the symptoms can even develop fully, their immune system fights it off thus resisting infection.
Does having the common cold help prevent COVID 19?
Scientists think that in some people who are naturally resistant to the COVID 19 virus, it is due to their previous exposure to other Coronavirus variants for example the common cold. In this case, the immune system would bear the memory of the infection and when exposed to the COVID 19 virus would produce antibodies for it.
Another quest that is on is to find people who have their genes coded in such a way that makes them biologically resistant to the COVID 19.
If scientists are able to study what is the inherent gene combination that has this effect, it would make it possible to better the vaccine process and make it more targeted.
Could a genetic defect prove lucky?
Genetic defects end up causing symptoms that worsen people’s conditions, but in the case of the mysterious COVID 19 escapers, a genetic defect could prove to their advantage. Viruses bind to receptors on the cell surface and this is how they manage to enter the cell and replicate and cause infection.
In people who do not have this receptor, the virus cannot bind to anything and thus the infection cannot be caused. András Spaan, a professor of infectious disease at the Rockefeller University in New York says to Mic “It could well be that, in some individuals, there is such a defect in a receptor used by Sars-CoV-2.”
Until the search for people who are naturally and genetically immune to the COVID 19 virus, yields results, one can only assume that previous exposure to the virus variants or the missing receptor may be the possible causes. As for luck? Well, that certainly has shown to favour some of them.