Two new Omicron variants are spreading. Will they drive a new U.S. surge?
The subvariants BA.4 and BA.5 may dodge immunity, especially in unvaccinated people, possibly causing a spike in infections worldwide.
New versions of Omicron are again causing a surge of COVID-19 cases in South Africa, and studies show that these new subvariants are so different from the original version of Omicron that immunity generated from a previous infection may not provide much protection.
Dubbed BA.4 and BA.5, the new subvariants are nearly identical to each other, and both are more transmissible than the Omicron BA.2 subvariant. In South Africa, they replaced the BA.2 strain in less than a month. They are now responsible for a spike in South Africa’s COVID-19 cases, which have tripled since mid-April.
“If you were unvaccinated, what you got is almost no immunity to BA.4 and BA.5,” says Alex
