(Reuters) – The BA.2 sub-variant of Omicron was estimated to be 23.1% of the coronavirus variants circulating in the United States as of March 12, the U.S. Centers for Disease Control and Prevention (CDC) said on Tuesday. Scientists are tracking a rise in cases caused by BA.2, which is spreading rapidly in parts of Asia and Europe. According to the CDC’s data, the sub-variant now makes up 39% of total cases in regions including New Jersey, New York, Puerto Rico and Virgin Islands. In states such as Connecticut, Maine, Massachusetts, New Hampshire, Vermont and Rhode Island, the sub-variant now …