Two new
subvariants of the Omicron strain now make up 70% of the United States' COVID cases, according to the CDC.
The variants,
known as BA.4 and BA.5, are reportedly the most contagious to date.
Officials say
currently available COVID vaccines
offer strong protection to
severe illness, but it appears BA.5 evades some protection offered by the shots
and prior infection.
Vaccine
manufacturers are currently working on Omicron specific
COVID shots, which are expected to be made
available in the fall.