Los Angeles, May 6 : New Omicron subvariant XBB.1.16 continues to spread rapidly in the US, with its prevalence increasing to 12.5 per cent this week, according to the latest data updated by the US Centers for Disease Control and Prevention (CDC). The subvariant, referred to as "arcturus," has become the second dominant strain in the country. It is estimated to account for about 12.5 per cent of new Covid-19 cases this week, up from 8.4 per cent last week, Xinhua news agency reported, citing the CDC data. Experts warned that the percentage is expected to increase in the coming weeks, with XBB.1.16 possibly becoming the next dominant coronavirus strain in the country. The highly transmissible Omicron subvariant XBB.1.5 remains the dominant strain in the US, and accounted for about 66.9 per cent of new Covid-19 cases this week, CDC data showed. /IANS