A new hybrid COVID-19 virus is 'one to watch', according to Professor Luke O'Neill.
The professor of biochemistry at Trinity College Dublin (TCD) says we need to know more about this new variant.
He told The Pat Kenny Show it has only been discovered in a few samples in the United States.
"It's a hybrid between Omicron and Delta - they've seen it in 17 samples in the US.
"But nothing to worry about yet, let's put it that way - very early days.
"But there's some evidence of a hybrid virus emerging.
"And of course the question is: how common is it going to be, how will it differ?
"There's loads of these things keep cropping up the whole time, and sometimes the media gets a hold of them.
"But it's another one to watch, I guess is the message".
As the number of COVID-19 cases climbs in Ireland, Prof O'Neill explains why some people do not catch the virus.
"One example is one person had been exposed four times in different situations - a high dose virus - and they were given the virus, they were part of that trial, and they never caught it.
"And of course, one big reason is genetic.
"Resisting this disease is all about immune system, and some people have very robust immune systems.
"They're finding genetic markers now that really defend you - a big one is a thing called interferons.
"So some people: the virus goes in your nose, you make loads of interferons very very quickly, that kills the virus almost on contact and the disease never develops.
"This was known, but now there's good evidence.
"One big reason is if you're a good interferon producer: because that system is souped up in your body, you will resist this virus".