What is the subvariant of Omicron known as the 'stealth' variant?

A new variant within Omicron, named Omicron BA.2, has been detected in over 40 countries. What makes it different from the original Omicron BA.1 strain is that it BA.2 lacks the mutation that makes it as easy to detect with PCR tests, according to the UK Health Security Agency. This makes tracking the infection much more difficult as it may not show up as Omicron on a test.

“BA.2 is detectable by PCR…Depending on the PCR test used it may not look like BA.1. But it will still give a positive result," Cornelius Roemer, a computational biologist at Switzerland's University of Basel, wrote. “[It's] frustrating to see falsehood about non-detectability still around."

While not much is yet known about the variant, there is some cause for hope, as Omicron's lethality is less than that of previous variants.

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What is the danger from the subvariant?

Like with Omicron BA.1, the subvariant is extremely transmissible. The likelihood of catching it is much higher compared to the Delta variant, and it also has an additional 20 or so mutations which set it apart from the original Omicron.

While extensive testing has yet to be completed, scientists in Denmark believe the subvariant is treatable with current vaccines.

“It is expected that vaccines also have an effect against severe illness upon BA.2 infection," the Danish government-run disease center announced. Denmark currently has the highest proportion of Omicron BA.2 cases in the world, around 65 percent of new infections.

Compared to where the world was with dealing with the pandemic two years ago, there are many more treatments and systems available for health centers to deal with new variants. BA.2 is no different.

Has it reached the US?

Indications say that the subvariant is beginning to make headway in the US, particularly in California and Texas.