BA.2, also called "stealth omicron," is the dominant strain worldwide and responsible for a growing number of COVID-19 cases in the US. The US Centers for Disease Control and Prevention estimates that BA.2 made up 34.9% of COVID-19 cases in the week ending March 19.
In areas where the strain is more prevalent, it's likely contributing to a small increase in cases (New York) and hospitalizations (areas of New England), according to comments by CDC Director Dr. Rochelle Walensky at a White House COVID-19 Response Team Briefing last week.
