Explainer: Takes BA.2 version. What is known about it?

In the latest battle of coronavirus mutants, an extra-infectious version of Omicron has taken over the world.

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

The World Health Organization says it makes up about 94% of the sequenced omicron cases submitted to an international coronavirus database in recent weeks. And the Centers for Disease Control and Prevention says it accounted for 72% of new US infections last week.

A pathologist at Houston Methodist in Texas, Dr. Wesley Long said he has seen the BA.2 quickly become effective in his medical system. At the end of last week, the variant was responsible for more than three-quarters of cases in Houston Methodist hospitals. In less than two weeks, 1% to 3% of cases were due to BA.2.

“It’s not too surprising because it’s more contagious than the original Omicron”, Long said.

As the variant progresses, scientists are learning more about it. But they still do not know how this will affect the trajectory of the pandemic.

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There are a lot of mutations in BA.2. It has been dubbed the “stealth omicron” because it lacks the genetic characteristic of the original omicron that allows health officials to rapidly differentiate it from the delta variant using a definitive PCR test.

Scientists say one reason BA.2 is on the rise is that it is about 30% more contagious than the original omicron. In rare cases, research shows that it can make people sick even if they already have an omicron infection – although it does not seem to cause more serious illness.

The vaccines appear to be equally effective against both types of omicrons. For both, vaccination plus a booster provides strong protection against serious illness and death.

Have variants escalated matters?

Coronavirus cases rose in parts of Europe and Asia when BA.2 became dominant, and some scientists are concerned that the variant could increase cases across the US as well.

Besides being more contagious, it is spreading at a time when governments are easing restrictions designed to control COVID-19. In addition, people are taking off their masks and returning to activities such as travelling, eating indoors at restaurants and attending crowded events.

At this point, overall coronavirus cases in the US are still declining. But it has accelerated in some places, including New York, Arizona and Illinois. Health officials have also noted that the number of cases is becoming more unreliable due to the widespread availability of home tests and the fact that some people are no longer being tested.

“We are entering a phase where rising cases or waves can be very regional and can depend a lot on the level of vaccination in the community – and not just the level of vaccination but the timing of the vaccination,” Long said. said. “How long ago were they? Did people get boosters? Because we know immunity to the vaccine goes down a little bit over time.”

Long said he feels “very certain” that cases will eventually return to the US, whether because of BA.2 or some future variant. “If it’s BA.2,” he said, “it could be more than a wave or a speed boom.”

For now, COVID-19 hospitalizations and deaths are still falling nationally.

Are there any other types to be concerned about?

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

These include Delta and Omicron and hybrids of BA.2, and combinations of the original Omicron, also known as BA.1.

One recombinant that health officials are closely tracking is a BA.1-BA.2 hybrid called XE, which was first detected in the United Kingdom in January. About 600 cases have been reported, and scientists believe it may be about 10% more contagious than BA.

What should people do?

The advice of the experts remains the same: Take precautions to avoid COVID-19.

“The virus is still circulating there,” Long said. “Vaccination is still your best defense.”

Get the shots if you haven’t already, and get a second booster if you’re eligible because you’re 50 or older or have a compromised immune system.

“If cases start to rise in your community, think about assessing your level of risk,” Long said. “If you’ve stopped wearing a mask and worrying about distance and things… it’s time to re-establish those protective measures.”

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The Associated Press Department of Health and Science receives support from the Howard Hughes Medical Institute’s Department of Science Education. AP is solely responsible for all content.

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