A new omicron subvariant, BA.2.12.1, is taking hold in the U.S. and was the second-most widely spread form of the coronavirus last week, according to a report published Tuesday by the Centers for Disease Control and Prevention.
BA.2.12.1 made up 19% of total U.S. cases the week ending April 16, increasing its spread by almost 67% from the week before. The CDC says omicron variants overall cause less-severe illness, although they spread faster than previous variants like delta.
Mutations in COVID variants are allowing the virus to dodge protection offered by vaccines in some cases, Andy Pekosz, a professor at the Johns Hopkins Bloomberg School of Public Health, told CNN.