In the latest battle of the coronavirus mutants, an extra-contagious version of omicron has taken over the world. The coronavirus version known as BA2 is now dominant in at least 68 countries, including the United States.The World Health Organization says it makes up about 94% of sequenced omicron cases submitted to an international coronavirus database in the most recent week. And the CDC says it was responsible for 72% of new US infections last week. From the AP:
- Rapid dominance. Dr. Wesley Long at Houston Methodist in Texas says he’s seen BA2 quickly become dominant 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. Less than two weeks earlier, 1% to 3% of cases were caused by BA2. "It’s not terribly surprising because it is more contagious” than the original omicron," Long says.
- "Stealth omicron." As the variant advances, scientists are learning more about it. But they still don’t know exactly how it will affect the trajectory of the pandemic. BA2 has lots of mutations. It’s been dubbed "stealth omicron" because it lacks a genetic quirk of the original omicron that allowed health officials to rapidly differentiate it from the delta variant using a certain PCR test.
- Why it's gaining ground. One reason BA2 has gained ground, scientists say, is that it’s about 30% more contagious than the original omicron. Besides being more contagious, it’s spreading at a time when governments are relaxing restrictions designed to control COVID-19. Also, people are taking off their masks and getting back to activities such as traveling, eating indoors at restaurants and attending crow,ded events.
- Vaccines are still effective. In rare cases, research shows it can sicken people even if they’ve already had an omicron infection—although it doesn’t seem to cause more severe disease. Vaccines appear equally effective against both types of omicron. For both, vaccination plus a booster offers strong protection against severe illness and death.
- It may cause a "speed bump." At this point, overall coronavirus cases in the US are still on the decline. But there have been upticks in some places, including New York, Arizona, and Illinois. Health officials have also noted that case counts are getting more unreliable because of the wide availability of home tests and the fact some people are no longer getting tested. Long said he feels “very certain” that cases will eventually go back up in the U.S., whether that's because of BA2 or some future variant. "If it’s BA2," he says, "it may be more of a wave or a speed bump than a surge."
- Other variants. As the coronavirus continues to evolve, the WHO is tracking other mutants, including hybrids known as "recombinants." These include combinations of delta and omicron and hybrids of BA2 and the original omicron, also known as BA1. One recombinant that health authorities are tracking closely is a BA1-BA2 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 BA2
- What people can do. The advice from experts remains the same: Take precautions to avoid getting COVID-19. "The virus is still out there circulating," Long says. "Vaccination is still your best defense."Get the shots if you haven't already, he says, and get the second booster if you’re eligible because you are 50 or older or have a compromised immune system. "If cases start going up in your community, think about assessing your risk level," Long says.
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