Doctor Explains Four Reasons Why Some People Don't Get Covid

A doctor has offered up four reasons as to why some people don’t contract Covid-19. 

Ever since the pandemic began, some people have fallen ill numerous times with the virus while others have avoided it altogether despite being in close contact with those who tested positive. 

Dr Cliona O'Farrelly, a professor of comparative immunology and biochemistry at Trinity College Dublin, spoke on RTE’s Claire Byrne Live radio show to explain why this might be the case. 

She puts it down to four reasons, including those cited previously by experts such as socio-economic backgrounds, good overall health and careful behaviour.

The less obvious cause is called an innate immune response signature, something that is currently being studied to see if certain people are resistant to the virus.

O'Farrelly explained: "How people live has got a lot to do with their circumstances and then on top of that then is this percentage of people who have what we would call an innate immune signature, that's what we're looking for…

“So I think those four things are really important; your socio-economic status, your general health well-being, how you behave and then this innate resistance."

Dr O'Farrelly and the team at Trinity have been studying a group of women who contracted Hepatitis C through blood transplants while others were naturally protected. 

Similarly to Covid-19, she believes that this could be down to the innate immune response.

The doctor said: "We do have data now that the women who did not become infected had a more innate immune response, that's an immune response that kicks in immediately on encountering the virus and it is the part of the immune system that is right at the site of where the virus is."

Now, O'Farrelly is among a team of researchers are also looking into whether this is the case with Covid, adding: “Flu is a totally different type of virus. The viruses come from very different families and just because you’re resistant to one does not necessarily mean you’re resistant to the other.

“But, this is what we would be wanting to research.”

The international consortium of experts are looking into Covid-19 resistance by studying people from 40 different countries who didn’t get the virus despite being in close contact. 

Dr O'Farrelly said: "Ideally we are looking for people who have resisted the virus twice, during the first wave and more recently with the Omicron and ideally we need people whose partner was PCR positive while they shared a room with them and they remained PCR negative."

This isn’t an easy task, as they’re looking for genetic markers of resistance, which means having to sequence the whole genome of participants. 

She added: “It’s like looking in a haystack, because the human genome is so variable but we are anticipating that we will see some mutations in the innate immune gene that give people resistance."

Those who live in Ireland and who think they qualify for the study can apply here, and even if you don’t, O'Farrelly offered up some advice amid the recent rise in Covid cases and hospitalisations.

“People should still be careful because again it's the vulnerable who are going to really suffer and also it's the healthcare system," she explained.

“The health care workers are just exhausted and it's them having work on skeleton staff that is causing huge difficulty. We really should be looking after them now.”

Speaking about what to expect in the future, she concluded: "Unfortunately, this is going to go on. 

“This virus is swirling around and so we are so privileged in this country to be vaccinated several times with boosters and more vaccines coming down. 

“It's going to keep coming back until the whole world is immune really."