(HealthDay News) — The new Omicron subvariant, BA.2, is spreading across the United States and will soon take over as the major COVID variant, White House chief medical adviser Dr. Anthony Fauci said Tuesday.

“Ultimately it will be the predominant variant in this country,” Fauci told HealthDay. “It’s occupying about 85% of the variants in the world, and somewhere around 30%-plus of the variants in the United States. It has what’s called the transmission advantage, which means it transmits a bit more efficiently than the BA.1, which is the original Omicron variant.”

However, Fauci and other infectious disease experts do not believe BA.2 will wreak the sort of havoc caused by earlier variants.

COVID cases might rise, perhaps even surge in some locales, but the experts are cautiously optimistic that BA.2 will not cause a sharp increase in hospitalizations and deaths — or an immediate need to return to masking and social distancing.

That’s partly because BA.2 is not a completely new COVID variant, as were Delta and Omicron, noted Dr. William Schaffner, medical director of the National Foundation for Infectious Diseases.

“You can almost think of it as ‘Son of Omicron.’ It’s slightly different, but not very different,” Schaffner said.

“It appears to be even more contagious than Omicron is, if you can imagine,” Schaffner continued. “But there are two characteristics about BA.2 that are fortunate. The first is that it appears not to produce more severe disease. And the second is that it would appear our current vaccines provide just about the same degree of protection against BA.2 that they do against Omicron.”

Omicron BA.2 is rolling through the United Kingdom and the European Union, and those countries are providing a forecast for what Americans might expect, said Fauci, who is also director of the U.S. National Institute of Allergy and Infectious Diseases.

“They are having an uptick in cases that does not seem to be accompanied by an uptick in severity of disease as manifested by an unusual increase in hospitalizations,” Fauci said. “So, even though there appears to be more cases, they’re not seeing an increase in utilization of intensive care unit beds, which is a reflection that there does not appear to be more severity of disease associated with BA.2.”

Protection from hospitalization, if not infection

Sadly, scientists have learned that vaccine protection appears to wane “pretty easily” in both the vaccinated and those who’ve suffered a natural infection, Fauci noted.

“If you look at the vaccine efficacy and you measure just symptomatic infection, after a few months following either infection and/or vaccination you have a rather significant diminution of vaccine efficacy,” Fauci said.

“What appears to hold up, even after several months, is protection against hospitalization,” Fauci said. “The bottom line is it’s much easier to protect against hospitalization than it is to protect against infection.”

So, although you might have a greater chance of catching a mild case of BA.2, if you’re vaccinated and boosted your chances of landing in the emergency room are low, experts said.

“People that are vaccinated and boosted, they don’t seem to be having a significantly increased hospitalization rate of serious illness between BA.1 and BA.2,” said Dr. Aaron Glatt, chief of infectious diseases at Mount Sinai South Nassau in Oceanside, N.Y. “BA.2 is more contagious than BA.1, but it’s also a fact that BA.2 is not more dangerous than BA.1. Those are two facts we can take to the bank.”

Glatt also suspects that places hit hard by Omicron will not receive a one-two punch from BA.2, since the two are very nearly the same. Natural immunity acquired from the original BA.1 variant will likely carry over to some extent to BA.2.

Because of these factors, infectious disease experts don’t expect masking and social distancing requirements to be reinstituted wholesale due to BA.2, even if case counts begin to rise.

The U.S. Centers for Disease Control and Prevention recently updated its community COVID tracking to focus on hospitalizations more than case counts. If BA.2 isn’t causing more hospitalizations, then communities won’t come under pressure to bring back masking.

Timing also plays a role — BA.2 is gaining steam as the spring and summer months begin in the United States, said Dr. Abinash Virk, an infectious disease specialist with the Mayo Clinic in Rochester, Minn.

“There’s more ability to be outside and do more outdoor stuff, so indoor activity concentration goes down,” Virk said. “Hopefully the infection rates will not be as high as they were with Omicron BA.1.”

Vaccines remain best protection

Experts continue to recommend that people get vaccinated and boosted against COVID, to prevent hospitalizations and better protect against BA.2.

“We’ve still got to do better with vaccination,” Fauci said. “We only have 65% of the total population fully vaccinated. Of those who’ve been vaccinated, only 50% of them have had their booster.”

And people at increased risk of severe COVID — the unvaccinated, elderly or the immune-compromised — should consider still wearing a mask and maintaining social distance as BA.2 spreads, Virk added.

“On an individual level, I think people may still continue to make decisions for themselves,” Virk said. “Some days I wear a mask to go to the grocery store, and sometimes I don’t. It just depends on how crowded it is and those kind of things.”

Finally, there’s always the chance that another COVID variant will emerge that poses an even greater threat, the experts said. Such a thing could completely turn over the card table.

“A new variant could occur that might evade the protection of our current vaccines,” Schaffner said. “If that happens, then Katie, bar the door, we’ll have to start over.”

“That is something that is a possibility, and we’ve got to be prepared for it,” Fauci said of another new COVID variant surfacing. “Remember, we’ve had variants that have come out of nowhere and surprised us. Delta did not originate in the United States. It originated in India. Omicron originated in southern Africa.

“As long as there’s a lot of viral dynamics throughout the world, there’s always a risk of a variant emerging that’s very different from what we’ve experienced now,” Fauci continued. “Although we’re all pleased that we’re heading in the right direction and that we continue to have a diminution in cases and in hospitalizations and deaths, we can’t be overconfident. We must be prepared for the eventuality of having another variant.”

More information

The World Health Organization has more about Omicron BA.2.

Source: HealthDay