New omicron subvariant makes up nearly half of COVID cases: What to know

Julia Marnin
McClatchy Washington Bureau (TNS)

A new omicron subvariant is on the rise and now makes up nearly half of COVID-19 cases in the U.S., according to Centers for Disease Control and Prevention data estimates updated on May 10.

Throughout the country, infections and hospitalizations are increasing, the agency reported on May 5. All current cases are caused by the omicron family.

Here’s what to know about the new subvariant, or sublineage, known as BA.2.12.1.

Omicron BA.2.12.1 is responsible for 42.6% of COVID-19 cases for the week ending May 7, CDC data estimates show.

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It emerged in early March just weeks before the stealth omicron subvariant — BA.2 — surpassed the original omicron strain — BA.1 — as most dominant during the final week of March, according to the CDC.

The agency “is working to better understand BA.2.12.1, how it spreads, and how well existing treatments and vaccines for COVID-19 work against it,” the CDC said.

BA.2 makes up 56.4% of virus cases and dominates overall. This comes after BA.2.12.1 cases have risen by roughly 10 percentage points in the past couple of weeks.

What is known about BA.2.12.1 so far?

“Some early evidence suggests BA.2.12.1 is increasing in variant proportion faster than other Omicron sublineages,” according to the CDC.

New variants are expected to “emerge and disappear as they compete against each other and other circulating viruses.”

Each omicron subvariant has descended from BA.1, omicron’s “parent lineage,” according to the CDC.

The new subvariant, BA.2.12.1, was first detected in upstate New York, CDC Director Dr. Rochelle Walensky said during an April 26 news briefing.

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CDC data shows BA.2.12.1 makes up the majority of cases, or 66.3%, in what is known as region 2 of the U.S. — New Jersey, New York, Puerto Rico and the Virgin Islands — as of May 7.

As omicron mutates, its subvariants “may differ in the public health risk it poses, including the change in epidemiology and or the severity profile,” the World Health Organization wrote in a report published May 4.

When it comes to BA.2.12.1, “the good news is that, so far, (it) does not appear to cause severe illness and death,” Yale Medicine reported on April 20.

Walensky echoed this during the news briefing and said “epidemiologically, it doesn’t appear as if we’re seeing more severe disease in places that are having more cases.”

However, she noted that BA.2.12.1 is potentially 25% more transmissible than BA.2.

What are symptoms of BA.2.12.1?

It is likely too early to determine whether symptoms of BA.2.12.1 differ from other variants because of how new it is, health experts told Medical News Today.

One expert, Elizabeta Mukaetova-Ladinska, a psychiatry professor focusing on old age in the U.K. at the University of Leicester, told Medical News Today that BA.2.12.1 might cause symptoms similar to BA.2.

Reported BA.2 symptoms include headache and body aches, sore throat, as well as gastrointestinal symptoms such as nausea, vomiting and diarrhea, according to the American Medical Association.

Dr. Dana Hawkinson, an assistant professor of infectious diseases at The University of Kansas Medical Center, told Medical News Today that preliminary data “suggests BA.2.12.1 has increased ability to infect the lower respiratory tract (lungs) compared to BA.1 Omicron, which could be one factor in its overall risk of severe disease.”

General signs of a COVID-19 infection, according to the CDC, include:

  • Fatigue
  • Fever/chills
  • Cough
  • Sore throat
  • Trouble breathing
  • Congestion/runny nose
  • Headache and body aches
  • Onset of loss of smell or taste
  • Gastrointestinal issues

What’s next?

“Additional evaluation is currently underway to understand the impact of BA.2.12.1 on vaccine effectiveness,” Walensky said during the April 26 news briefing.

“We continue to believe that those who are vaccinated and especially those who are boosted continue to have strong protection against severe disease, even from BA.2.12.1,” she added.

A professor at Duke University Medical Center’s Human Vaccine Institute, David Montefiori, told NBC News that “at some point, you just can’t get nervous every time there’s a new variant, because there’s always going to be a new variant.”

Living with COVID-19 is likely becoming the “new normal,” three Food and Drug Administration officials wrote in a paper published in the journal JAMA on May 2, McClatchy News previously reported.

The FDA is considering a potential update to the composition of COVID-19 vaccines to “benefit” people of all ages against the virus and its variants, according to the paper. This will need to be decided ahead of fall and winter based on the variants spreading.