(CNN)The highly contagious Omicron subvariant BA.2 is now the dominant strain of Covid-19 in the United States, causing an estimated 54.9% of all new Covid-19 infections last week, according to new data from the US Centers for Disease Control and Prevention.
The hardest hit region continues to be the Northeast, where BA.2 is causing more than 70% of all cases. The South and Mountain West are seeing the fewest cases in the US. BA.2 is causing slightly more than one-third of infections in those regions.
This is a developing story and will be updated.