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Omicron subvariant BA.2 is rising. What do we know about it?


Two years into the COVID-19 pandemic, and just when new cases and hospitalizations in the U.S. are on the decline, an Omicron subvariant called BA.2 is gaining significant traction in some parts of the world.

Dr. Dorit Nitzan, a World Health Organization regional director, told the Jerusalem Post on Monday that Omicron BA.2 is likely to become dominant worldwide due to its high transmissibility. “The expected trajectory is that it will become the new dominant variant, as once it crosses past a certain threshold it becomes dominant — like we’re seeing in Denmark and the U.K.,” Nitzan said.

While the original Omicron variant, first detected in South Africa in late November, is still responsible for the majority of new cases in most countries, BA.2 has rapidly spread in places such as South Africa, India, England and Denmark, where it is now dominant.

In the U.S., Omicron BA.2 is circulating at a low level, accounting for less than 4 percent of new coronavirus cases, according to the Centers for Disease Control and Prevention. But some experts believe it is just a matter of time until the subvariant takes over and becomes dominant.

“Anytime a variant is more transmissible, even if it’s a little more transmissible, it seems to have taken on that dominance,” Dr. Monica Gandhi, an infectious disease specialist and professor of medicine at the University of California, San Francisco, told Yahoo News. “So Delta was much more transmissible than Alpha. It took over. Then Omicron was four times more transmissible than Delta. It took over. If the BA.2 is more transmissible than BA.1, it’ll take over,” she said.

According to public health experts in both Denmark and the U.K., the variant appears to be between 30 and 34 percent more infectious than the currently dominant BA.1 form. A recent Danish study also found that BA.2 was relatively better than BA.1 at infecting vaccinated people, which indicates the subvariant has greater “immune-evasive properties.”

But, underscoring the value of vaccines, the researchers found that vaccinated people were still less likely to get infected and transmit either the BA.1 or BA.2 subvariant compared with unvaccinated people.

The good news is that there are no indications so far that BA.2 causes more severe disease. In addition, Gandhi says it’s a good sign that the subvariant hasn’t accelerated the pandemic in Denmark and the U.K. “Cases still were able to go down there, despite BA.2 coming into their regions,” Gandhi told Yahoo News.

Data on Omicron BA.2 is still limited, and it is uncertain what impact the strain will have on the future of the pandemic. Gandhi says booster shots are the best way to protect yourself and your community from both Omicron subvariants.

Her point is supported by recent U.K. data that showed booster protection against symptomatic COVID-19 infection was 70 percent for BA.2 and 63 percent for BA.1.

“What we need to get through this time is immunity. … If we got a booster, it would help raise our antibodies and stave off even mild infections. So getting a booster is an important strategy,” Gandhi said.

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