Long Covid may be causing "ghosts" of the virus to linger within the body, according to Professor Luke O'Neil.
Professor O'Neill, who is a Professor of Biochemistry at Trinity College, was speaking from a conference in Philadelphia to Newstalk's Pat Kenny, explaining how a new study found remnants of the virus in the digestive tract of long Covid patients.
He said: "I'd say half the speakers at the conference here in Philadelphia are talking about long Covid because that remains a big concern, as you know, and the incidence of that are quite high, especially in the US because if you're unvaccinated, you've a higher risk of long Covid as well.
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He explained: "They've detected remanence of the virus in your gut it was a massive study 46 per cent of people who have long Covid they could detect these remanence in the tract, they also found B cells there to make antibodies against the remanence, and it looks as though these remanence are causing or may be the cause of long Covid symptoms."
Professor O'Neill hailed the new study as a "breakthrough" in the medical world, as it could mean a treatment for long Covid could be on the way.
He said: "Of course, that's an advance because if you can clear those reminisce out, say with an antiviral drug, for instance, you may have a way to treat it as well. So it's really seen as a huge breakthrough at the conference. There's a lot of excitement about that.
"It's the first big breakthrough in many ways in the understanding of long Covid, so it's a really good development."
Meanwhile, the scientists at the conference also urged anyone who has not yet gotten their vaccine or booster to do so as a fifth wave may be on the way.
Prof O'Neill said: "Last Friday, the WHO designated BA4 and BA5 as variants of concern, and they're the first variants of concern since Omicron, and they're now sweeping around the world. In Ireland, we probably have BA4 and BA5 among us.
He added: "South Africa are just coming out of a massive fifth surge. Now the good news there was the vaccination is holding up against BA4 and 5, and so they haven't seen the increase in hospitalisations, unlike in the US, where the vaccination rate was lower. That's what's causing this big spike in hospitalisations.
"So the prediction is, by the way, over the summer, BA4 and 5 will be responsible for the next surge in Europe. They will follow South Africa, which is on the way down, and as I say, very importantly, the vaccination does seem to be holding."
Professor O'Neill previously said that a "variant proof" jab could be on the way this autumn as the US army is looking into a vaccine that could work against all variants.
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