In the latest battle of coronavirus mutants, a super-contagious version of the omicron has taken over the world.

The version of the coronavirus known as BA.2 now dominates in at least 68 countries, including the United States.

The World Health Organization said it accounted for about 94 percent of sequenced omicron cases submitted to the International Coronavirus Database in the latest week. The Centers for Disease Control and Prevention said it was responsible for 72 percent of new infections in the U.S. last week.

Dr. Wesley Long, a pathologist at Houston Methodist Church in Texas, said he saw BA.2 quickly take over his healthcare system. Over the weekend, more than three-quarters of cases at Houston Methodist Hospital were caused by the variant. Less than two weeks ago, 1% to 3% of cases were caused by BA.2.

“That’s not surprising, since it’s more contagious than the original omicron,” Long said.

As the variant develops, scientists are learning more about it. But they still don’t know how this will affect the trajectory of the pandemic.

known

BA.2 has many mutations. It’s called the “stealth omicron” because it lacks the genetic quirks of the original omicron, allowing health officials to use some sort of PCR test to quickly distinguish it from the delta variant.

One reason for BA.2’s success, scientists say, is that it is 30 percent more infectious than the original omicron. In rare cases, studies have shown that omicron can make people sick even if they are already infected — although it doesn’t appear to cause more serious disease.

The vaccine appears to be equally effective against both types of omicron. In both cases, vaccination and booster immunization can provide strong protection against severe disease and death.

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Did the variant push the case up?

While BA.2 dominated, coronavirus cases rose in parts of Europe and Asia, and some scientists fear the variant could also push cases up across the U.S.

In addition to being more contagious, it spreads as governments ease restrictions aimed at containing COVID-19. In addition, people are taking off their masks and restarting activities like traveling, dining at restaurants and attending crowded events.

Currently, overall coronavirus cases in the U.S. are still falling. But there have been increases in some places, including New York, Arizona and Illinois. Health officials also pointed to the widespread availability of home testing and the fact that some people are no longer getting tested, the number of cases has become increasingly unreliable.

“We’re entering a stage where the increased cases or waves could be very regional, and that could be very much dependent on the level of vaccination in the community — not just the level of vaccination, but the timing of the vaccination,” he said. Long said. “How long ago were they? Did people get boosters? Because we know that immunity to vaccines wanes a bit over time.”

Long said he’s “very certain” that cases in the U.S. will eventually rebound, either because of BA.2 or some future variant. “If it’s BA.2,” he said, “it’s probably more like a wave or speed bump than a surge.”

Currently, COVID-19 hospitalizations and deaths are still trending down nationwide.

Are there any other variants to watch out for?

As the coronavirus continues to evolve, the World Health Organization is tracking other mutants, including hybrids known as “recombinants.”

These include a combination of delta and omicron and a mixture of BA.2 and original omicron (also known as BA.1).

One recombinant being closely tracked by health authorities is a BA.1-BA.2 hybrid called XE, which was first detected in the UK in January. About 600 cases have been reported, and scientists believe it may be about 10% more contagious than BA.2.

What should people do?

Expert advice remains the same: Take precautions to avoid contracting COVID-19.

“The virus is still spreading outside,” Long said. “Getting vaccinated is still your best defense.”

If you haven’t had the shot, if you’re eligible because you’re 50 or older or have a compromised immune system, get a second booster shot, he said.

“If cases in your community start to increase, consider assessing your level of risk,” Long said. “If you stop wearing masks, stop worrying about distance and other things… that’s time to re-enact these protections.”