A leading medic has explained why some people don't catch Covid-19. She said there were four main reasons why some people are immune - and said a new study has been launched to dig deeper.
Speaking on the Claire Byrne TV show in Ireland, Dublin-based immunologist Dr Cliona O'Farrelly said some people have managed to escape contracting Covid-19 during due to their socio-economic background, general good health, careful behaviour and a rare innate immune response.
Dr O'Farrelly, who is also a professor of comparative immunology and biochemistry at immunology at Trinity College, said: "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. The innate immune signature that identifies the resistance so I think those four things are really important - your socio-economic status, your general health wellbeing, how you behave and then this innate resistance."
Dr O'Farrelly has also for several years worked on a study about women who contracted Hepatitis C through blood transplants and why some women did not contract the virus. She believes it is down to the innate immune response similarity with Covid-19, reports DublinLive.
She explained: "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. A whole lot of people are not becoming infected because they're being super careful and they're to be congratulated. But in addition to the people who are not getting it because they're very careful there are those with an innate immune system, and we believe that the innate immune system is able to keep the virus away without becoming infected at all."
Dr O'Farrelly said there was currently a huge international consortium studying people from 40 countries who have not become infected from Covid-19 despite being close contacts of the virus. At the moment, they are seeking people from Ireland who have never had Covid to take part in the large study.
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."
She said that the study is looking for "genetic markers" of resistance to infection. She added: "It means having to sequence the whole genome of the people and it's like looking in a hay stack, 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."
Asked about recent increased hospitalisations with Covid, Dr O'Farrelly added: "People should still be careful because again it's the vulnerable who are going to really suffer and also it's the healthcare system, 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."
Dr O'Farrelly said that we can expect more variants to emerge: "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."
Find out more about the new study on Covid-19 resistance here.
