(AP) – A new omicron mutant that is a descendant of the earlier “stealth omicron” has quickly gained ground in the United States. The U.S. Centers for Disease Control and Prevention said Tuesday that it was responsible for 29% of new COVID-19 infections nationally last week. In the New York region, it caused 58% of reported new infections. It’s also been detected in at least 13 other countries. Scientists say it spreads even faster than the super-contagious stealth omicron and are now trying to figure out how effective vaccines are against it.