PROVIDENCE – The omicron variant has been detected in more than two dozen countries, including just this week in the U.S.  

And this much is certain, says pandemic expert Dr. Ashish Jha: it will continue to spread. 

Beyond that, Jha asserts, uncertainties at this early stage abound, just as they did when the last major variant, Delta, was first found in India about a year ago. 

During recording of the latest “COVID: What Comes Next” podcast, Jha, dean of Brown University’s School of Public Health, said he and other scientists are concerned with three major issues as they monitor developments. 

-- Ease of transmissibility, which the Delta variant has abundantly demonstrated, is one. 

“There's some data out of South Africa that suggests that it might be spreading very quickly in South Africa, but just because it does there does not mean it's going to spread more easily here,” Jha said. “The short answer is we don't know.” 

But he added: “If Omicron is as contagious or more contagious than Delta, [most regions] will end up encountering this variant as well.” 

-- A second issue is severity. 

“Does it cause more severe disease?” Jha said. “We have no idea. You may have heard stories of somebody who had mild disease, but individual cases, anecdotes, don't tell you the story. We have to look at a lot more data. We don't know if it causes milder disease or more severe disease. Obviously, we all hope it causes more mild disease, but we don't know.” 

-- A third is evasiveness, “the big issue,” as Jha described it. 

“Does it break through our vaccines?” Jha said. “We don't have the data, but here's what concerns so many of us: the mutations we see with omicron are in parts of the virus where our vaccines usually work -- the parts of the spike protein where our vaccines work. That's where we're seeing the mutations and that's what's concerning many of us.” 

Jha expects answers here relatively quickly. 

“We will get more data in the next week to 10 days,” he said. “We don't have to wait months.” 

Regarding the three current COVID vaccines – Pfizer, Moderna and Johnson & Johnson – and their potential defense against omicron, Jha was asked: “Is it better to be vaccinated than to be unvaccinated?” 

“Oh my goodness, not even a close call,” Jha said. “Let's say our vaccines work a little less well. Is there any chance vaccine effectiveness goes to zero, meaning the vaccines atop working completely against omicron? There's essentially no chance in my mind that vaccines will stop working altogether.  

“So if you've been vaccinated, you'll still have some degree of protection. And most of us believe, [given] our understanding of how boosters work, that if you are fully boosted, you actually will probably have a pretty high degree of protection against Omicron.” 

Jha’s advice? If you are not vaccinated, do so. And if you are eligible for a booster shot but not yet gotten it, do so. 

During the podcast, Jha also explained why unvaccinated people who become infected with coronavirus are much more likely than vaccinated people to serve as a sort of haven in which mutations are more likely to occur. The reason, he said, is the more frequently a virus replicates, the greater the chance that one or more replications will carry a mutation. 

 “Vaccinated people most times won't even get infected, so the virus is not going to be multiplying,” Jha said. “Even if you get infected, [the virus] will be there for a much shorter period of time and you're not going to give the virus as much chance to mutate. 

“No question there's a lot more replication happening among unvaccinated people and replication is the heart of mutations that lead us to” variants such as omnicon. 

This is the 39th episode of the “COVID: What Comes Next” podcast, begun in October 2020 and available exclusively from The Providence Journal and the USA TODAY NETWORK. It is hosted by G. Wayne Miller, health reporter for The Providence Journal.