The newer and most contagious Omicron subvariants, known as BA.4 and BA.5, now make up more than 80 percent of Covid-19 infections in the US, according to data released by the US Centers for Disease Control and Prevention (CDC).
The BA.5 subvariant accounted for 65 per cent of new infections in the latest week ending July 9, while BA.4 accounted for 16.3 per cent of new infections, CDC data showed on Tuesday.
BA.5 has become the dominant variant in the US, Xinhua news agency reported.