BA.2 now dominant COVID variant: Will it cause another spike in the US?

(NEXSTAR) – The BA.2 variant of COVID-19, also known as "stealth omicron," has become the dominant variant of the coronavirus around the world, the World Health Organization said Wednesday. The omicron subvariant now accounts for 75% of coronavirus cases globally.

"This is the most transmissible variant we have seen of the SARS-CoV-2 virus to date," said Dr. Maria Van Kerkhove, the WHO's COVID-19 lead.

The BA.2 variant has driven a rapid increase in COVID-19 cases in several countries around the world over the past few weeks, including China, Australia and much of Europe.

"These increases are occurring despite reductions in testing in some countries, which means the cases we're seeing are just the tip of the iceberg," said WHO Director General Dr. Tedros Adhanom Ghebreyesus.

Will the United States see a spike in COVID-19 from the BA.2 variant of omicron?

BA.2 has yet to become dominant in the U.S. It currently accounts for about 23% of COVID-19 cases nationwide, according to the Centers for Disease Control and Prevention.

The fact that we saw such a huge spike from BA.1, the other omicron subvariant, just a couple of months ago may protect us from another massive surge, experts say. One recent model estimated 73% of Americans had immunity to the omicron variant because so many were exposed between December and February.

Still, that would mean about 27% of Americans are not immune – nearly 90 million people.

Those who haven't gotten a COVID booster shot and people over 65 are especially vulnerable.

"It's that group that's most problematic when it comes to the severe critical and fatal disease. It doesn't mean that younger folks don't wind up in the hospital at times; it's just not at the same rate," Jeffrey Shaman, of Columbia University's Mailman School of Public Health, told CNN.

Pfizer is seeking authorization to offer a fourth shot of its vaccine to seniors to boost their protection.

In the meantime, the CDC advises everyone stay up to date on their COVID vaccine. Whether or not you're "up to date" depends on your age, health conditions, the type of COVID shot you got, and how long it's been since your last dose.

As long as the virus continued to circulate, it will continue to spawn new variants – some of which could prove more contagious, more immune-evasive, or more deadly.

"The virus will pick up pockets of susceptibility and will survive in those pockets for months and months until another pocket of susceptibility opens up," said Dr. Michael Ryan, a WHO executive director. "This is how viruses work. They establish themselves within a community and they'll move quickly to the next community if it's unprotected."