Which subvariants are circulating right now? And what is the ‘nightmare variant’? According to the Centers for Disease Control and Prevention, the BA.5 subvariant, which powered the summertime COVID-19 surge, still causes just under half of infections across the country. But two other subvariants are growing rapidly and are expected to outcompete BA.5 very soon: BQ.1 and BQ.1.1. As of last Friday, BQ.1 accounted for 14% of COVID-19 infections in the United States, while BQ.1.1 accounted for 13.1%. Another variant, called BA.4.6, has also gained some ground since August. It now accounts for 9.6% of cases. BF.7, BA.5.2.6, BA.2.75 and...