The new COVID-19 variant of concern, a subvariant of omicron, has been called "stealth omicron" because it doesn't seem to show up on PCR tests in the same way, CNN reported Feb. 17. That means labs have to take an extra step and sequence the virus to find the new variant.
"Establishing a method to detect BA.2 specifically would be the first thing" many countries need to do, University of Tokyo researcher Kei Sato, PhD, told CNN.
Ten things to know about the new variant, according to the report and a preprint study that hasn't yet been peer reviewed:
1. It appears to largely escape the immunity created by vaccines. A booster shot restores protection, however, reducing the chance of illness after infection by about 74 percent.
2. The new variant is resistant to some treatments, including the monoclonal antibody that's currently being used against omicron.
3. Antibodies in the blood of people who have recently had omicron appear to have some protection against BA.2, especially if they've been vaccinated.
4. The variant has dozens of gene changes that are different from the original omicron strain, making it as distinct from the most recent pandemic virus as the alpha, beta, gamma and delta variants were from each other.
5. It is about 30 to 50 percent more contagious than omicron.
6. It has been detected in 74 countries and 47 U.S. states.
7. The CDC estimates that about 4 percent of Americans with COVID-19 now have infections caused by the BA.2 variant.
8. BA.2 can copy itself in cells more quickly than the original version of omicron.
9. It's better at causing cells to stick together, which allows the virus to create larger clumps of cells — which then become factories for churning out more copies of the virus.
10. It has become dominant in at least 10 other countries: Bangladesh, Brunei, China, Denmark, Guam, India, Montenegro, Nepal, Pakistan and the Philippines.