Another new subvariant, BA.4, accounted for 12.8 per cent of new infections, CDC data show.
The two contagious subvariants now made up over 90 per cent of new infections in the US.
Confirmed cases contracted by the two subvariants kept increasing since mid-May, CDC data show.
The two subvariants are more contagious than earlier variants of Omicron, and also appear to evade protection from vaccines and previous infections more easily than most of their predecessors, according to health experts.
Source: IANS
