A new COVID variant could be the one to "watch out for" this year after a surge in cases in the US, an expert has said. Tim Spector, professor of genetic epidemiology at King's College London, highlighted an Omicron variant after a scientist said cases had more than doubled in America in a week. More than 40% of COVID cases in the US are now caused by the XBB.1.5 variant, according to data from the Centres for Disease Control and Prevention (CDC) from Friday. In the northeast of the US, about 75% of confirmed cases are reported to be XBB.1.5....