The week ending Dec. 10, the variant known as XBB.1.5 was present in 17.7 percent of all samples tested in the CDC’s region 1, which includes all of New England from Connecticut north, according to CDC data. The variant was present in more than 75 percent of all samples tested by the end of the month, the week ending Dec. 31. XBB.1.5 is the dominant variant across the United States, according to CDC data, but it is nowhere near as widespread in other regions, present in 40.5 percent of samples tested. A team of Columbia University researchers wrote that XBB.1.5, along with other, less dominant variants, "exhibit far greater antibody resistance than earlier variants, and they may fuel yet another surge of COVID-19 infections." The variant “may be more transmissible than other variants, but we don’t know if it causes more severe disease,” the CDC said via Twitter on Dec. 30. As of Dec. 31, there were 719 patients fighting COVID infections in Connecticut hospitals, according to data maintained by the state Department of Public Health, a net increase of 141 over the previous seven days. There were 11 COVID-related deaths in Connecticut in the seven days ending Dec. 31, and a total of 11,781 patients have died as a result of COVID or suspected COVID infections in Connecticut.Researchers from Columbia University published a study in the journal Cell showing that the XBB.1.5 variant may have become "dominant" so quickly because of its "advantage in evading antibodies," presenting a "serious threat" to "current COVID-19 vaccines." Written By Jordan Nathaniel Fenster Jordan Nathaniel Fenster is a reporter with Hearst Connecticut Media Group. He is an award-winning reporter, podcaster and children's book author. He serves as senior enterprise reporter and lives in Stamford with his dog, cat and three daughters.