MONDAY, Jan. 31, 2022 (HealthDay News) — The so-called “stealth” variant of omicron is not likely to cause another devastating wave of COVID-19, experts say.
The new version of the variant, called BA.2, does not appear to cause more severe disease, and vaccines are just as effective against it as against the original omicron variant (BA.1), but BA.2 does show signs of spreading more rapidly. “This may mean higher peak infections in places that have yet to peak, and a slowdown in the downward trends in places that have already experienced peak omicron,” Thomas Peacock, a virologist at Imperial College London, told The New York Times.
Back in December, South African researchers discovered that a growing number of polymerase chain reaction (PCR) tests were failing to detect the spike gene — a sign that BA.1 was becoming dominant. Unlike BA.1, BA.2 lacks a key spike mutation. That can cause a PCR COVID-19 detection test to fail. Without the ability to use PCR tests to track BA.2, some scientists nicknamed it the “stealth” version of omicron, The Times reported. But BA.2 was not invisible: Researchers could still spot it by analyzing the genetic sequences of samples from positive tests. And once delta disappeared, scientists could use PCR tests to tell the difference between BA.1 and BA.2: Samples that caused spike failures contained BA.1, while the ones that did not contained BA.2.
An early analysis of BA.2 released Friday by the British government showed that BA.2 accounts for fewer cases there but is growing faster than BA.1 across England, The Times reported. However, British researchers have concluded that vaccines are as effective against BA.2 as they are against BA.1.
About 8 percent of cases in the United States are BA.2, and that percentage is rising quickly, according to Trevor Bedford, a virologist at the Fred Hutchinson Cancer Center in Seattle.
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