Researcher outlines why some people don't catch Covid despite partner having virus

Researchers have put forward reasons why some people don't catch Covid-19 despite sharing a bed with a partner with the virus. 

As part of a new project, researchers from Trinity College in Dublin are looking to speak to people as part of a study into couples who have shared beds while one was Covid positive and the other remained Covid negative.

Cliona O'Farrelly, Professor of Comparative Immunology & Biochemistry, Trinity College appeared on Today with Claire Byrne radio show earlier this week to discuss her research into why some people don't get Covid-19 despite living in close-confines with someone who is positive with the virus. 

"This is something that has been interesting me for a long time", she said.

She started studying immune responses after the Hepatitis C scandal, when a cohort of rhesus negative women got anti-D which was contaminated with Hepatitis C virus. Through this study she became interested in why some women got got the anti-D didn't get contaminated.

She said that the women who didn't get infected have a stronger "innate immune response", which "is the immune response that kicks in immediately on encountering the virus. It's part of the immune system that's right at the site where the virus is".

It is not just biology, however, that keeps some people from catching viruses and illnesses.

"We should make it clear that a whole lot of people are not becoming infected because they're being super careful", she said.

"They're to be congratulated and certainly for that to be continued. But in addition to the people who are not getting it, because they're very very careful, there are those whose innate immune system - that's what we believe and that's what we're studying - is able to keep the virus away without becoming infected at all."

Her research team is now looking for people who have resisted the virus, ideally twice, both in the first wave before vaccination and in recent months with Omicron.

"We need people whose partner was PCR positive while they shared a room with them, and they've been PCR negative," Ms O'Farrelly said. 

The Viral Resistance Project aims to identify who is resistant and how they are resistant.

Those behind the project said it could have a major impact on public health measures, vaccine development and basic understanding of viral infections.