As original omicron disappears, these are the BA.2 subvariant’s key differences

April 21, 2022
By demo12
Corona Virus
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The omicron variant of the coronavirus has been dominant in the U.S. since December, but the version of omicron that drove the major infection surge during the winter now accounts for less than 7 percent of new cases.

A more transmissible subvariant, BA.2, accounts for around three-quarters of U.S. cases. And BA.2, in turn, has spawned its own sublineage, BA.2.12.1, which appears to be gaining steam: It rose from 7 percent of U.S. cases in early April to 19 percent last week. The New York State Health Department said last week that BA.2.12.1 was most likely contributing to the state’s rise in case numbers.

So far, the key difference between the newer versions of omicron and the one that previously rocketed through the U.S. is transmissibility. The White House’s chief medical adviser, Dr. Anthony Fauci, has estimated that BA.2 is 50 percent more transmissible than the original omicron lineage.

But the coldlike symptoms vaccinated and boosted people feel as a result of an omicron infection are mostly the same regardless of the subvariant.

“The omicron symptoms have been pretty consistent. There’s less incidence of people losing their sense of taste and smell. In a lot of ways, it’s a bad cold, a lot of respiratory symptoms, stuffy nose, coughing, body aches and fatigue,” said Dr. Dennis Cunningham, the system medical director of infection control and prevention at Henry Ford Health in Detroit.

Symptoms of the BA.2 subvariant

The Zoe COVID Symptom Study in the U.K. has enabled hundreds of thousands of people to self-report their symptoms through smartphone apps.

One of the apps’ co-founders, Tim Spector, a professor of genetic epidemiology at King’s College London, said that based on Zoe data, a runny nose is still the most common symptom of omicron, followed by fatigue, a sore throat, sneezing and headache.

“The changes from BA.1 to BA.2 have been quite subtle — perhaps runny nose and fatigue [are] going up,” he said.

Spector said 84 percent of people in the U.K. who logged symptoms lately said they had runny noses, compared to around 73 percent in early January. Seventy-two percent said they had fatigue, up from 68 percent during the first omicron wave.

But it’s hard to attribute those changes directly to a subvariant, Spector said, because there are many confounding factors.

What should we make of all these omicron lineages?

BA.1 and BA.2 are about as genetically similar as delta was to alpha, experts said. Differences between the subvariants could influence the effectiveness of monoclonal antibody treatments.

“We know even with BA.1 and BA.2, which are both subtypes of omicron, that different monoclonal antibodies work for one but don’t work for the other,” said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security at the Bloomberg School of Public Health.

But experts generally agree that the public shouldn’t worry too much about the emergence of each omicron subvariant.

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