One expert has outlined the reasons why some people haven’t caught Covid-19 yet, despite having been close contacts.
Wearing masks and being cautious of the virus could just be part of the reason some people have avoided it.
Cliona O’Farrelly, a Professor of Comparative Immunology and Biochemistry at Trinity College Dublin, outlined the possible explanations why some people have not become infected with the virus, despite having been in contact with those who are infected.
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Alongside good practices such as wearing masks and hand hygiene, O’Farrelly said there are a number of factors that could result in certain people avoiding Covid-19.
Socioeconomic status, what a person’s living conditions are like and their level of general health could all contribute to how susceptible they are to contracting the virus.
However, some people could have what is called an ‘innate immune signature’ that identifies resistance to certain viruses, meaning that even if they are brought into contact with that virus, they may not become infected.
“In addition to the people who are not getting it because they’re very careful, there are those who are innate - that’s what we believe and that’s what we are studying - immune system is able to keep the virus away without becoming infected at all,” she told Claire Byrne on the host’s RTE radio show.
The professor said that the million-dollar question among an international consortium of researchers is why this might be the case among some people.
Volunteers who have avoided the virus thus far are needed both here and abroad to help this study to develop further.
“This consortium is looking for genetic markers of resistance to infection, so it means having to sequence the whole genome of the people who are resistant,” O’Farrelly said.
“It's like looking for a needle in a haystack because the human genome is so hugely variable but we’re anticipating that we’ll see some mutations in the innate genes that give people resistance.”
In a bid to understand resistance in general, O’Farrelly and the team in Trinity have also looked at hepatitis C. During this study, pregnant women were infected with hepatitis C, or HCV. Some were naturally protected and did not show signs of infection.
From the results, it was thought that some may be protected from other viral infections too, especially considering that HCV and SARS-CoV-2 are both RNA viruses.
“It may well be that a person who is resistant to HCV may be resistant to SARS-CoV-2,” she said.
However, this does not mean that you will be resistant to all viruses.
She said: “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.”
O’Farrelly said that it is “likely” that those who have an innate system would be resistant to other variants of Covid-19, which she believes we could see more of.
For those who may be considered more susceptible, such as those who may have underlying issues, the innate immune response may be able to provide resistance and prevent them from getting sick.
Similarly, O’Farrelly said: “We are anticipating that the genetic variation that might give resistance to virus might also make people more susceptible to auto-immune disease.”
Unfortunately, there are “just so many unanswered questions” that it’s hard to know for sure just yet how certain people have avoided the virus.
However, according to the professor, until the whole world is immune to Covid-19, it is just “going to keep coming back”.
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