What do we know about “stealth omicron” so far?

By VICTORIA MILKO
AP Science Writer

Scientists say an extra-contagious version of the omicron variant is spreading globally, but it doesn’t seem to cause more severe disease. Since the “stealth omicron” was first identified in November, it has been driving new surges in parts of Asia and Europe. BA.2 is now the dominant variant in the U.S. and more than five dozen other countries. COVID-19 vaccines appear just as effective against both kinds of omicron, offering strong protection against severe illness and death. Health officials are tracking other variants including XE — a combination of BA.2 and the original omicron. It’s not yet a variant of concern or interest.