The virus that causes covid-19 has mutated again and again, and experts say new variants will continue, in part because of the nature of the virus and also because large swaths of the population choose not to be vaccinated.

Every time the DNA virus divides, it makes an exact copy of itself.

That perfect-copy process doesn’t happen in RNA viruses, meaning there is a chance for change each time the virus replicates.

The virus that causes covid-19 is an RNA virus.

Whether a variant will be more severe or more transmissible is, for the most part, up to chance, Yassin said.

Viruses oftentimes can be changed or reengineered in a lab, he said, “but in nature, these changes are random?

“It’s almost impossible to know what is the next strain going to be,” he said.

Potentially exacerbating the issue, Yassin said, is the fact that many people are not vaccinated.

Nationwide, just under 222 million people are fully vaccinated — about two-thirds of the population.

“If you don’t have much (virus) going around, you’re going to have way less chance for mutation and new variants — that’s absolutely true,” he said.

Some studies suggested the delta variant was 80% to 90% more transmissible than previous variants, and it was found to cause much more severe disease in those who were vaccinated.

They were named variants of interest by the World Health Organization at the time.

“We didn’t call those variants of concern, but they were variants that were more transmissible,” said Dr.

“The virus is going to adapt as it passes its way through hundreds of millions and billions of people — going on and infecting and then reinfecting people,” said McCarthy, who is a member of the Pitt Center for Vaccine Research.

To achieve that goal, the virus can evolve to infect cells more efficiently, he said, and can even evolve to evade antibodies created during the illness.

Most of the time, nothing comes of it, he said, “but every once in a while, somebody wins the Mega Millions.”.

“That’s the million-dollar question,” McCarthy said.

“We are going to be living with this,” he said.

He said the best-case scenario would be one or two dominant variants at a time as opposed to myriad mutations making the rounds.

Fox said she believes that covid-19 eventually will look more cyclical.

“It has to do with what’s going on in our environment,” she said

Yassin, too, said he believes the virus could take on a more seasonal appearance, but noted that the real future of the illness, hospitalization and death from covid hinges on vaccinations