The Omicron subvariants BA.4 and BA.5 are behind an increasing portion of SARS-CoV-2 infections in the US, the New York Times reports.
Modeling from the US Centers for Disease Control and Prevention has found that these subvariants, which were first spotted in South Africa in early in 2022, now together account for about 13 percent of COVID-19 cases in the US. Early in May, for comparison, they accounted for 1 percent of cases.
In South Africa, the variants fueled a COVID-19 surge in April and May, though Columbia University's Jeffrey Shaman tells the Times that the wave there was not as sharp as previous ones. Some research has hinted that BA.4 and BA.5 may be able to spread faster and better escape immunity than earlier forms of Omicron.
The Times adds that BA.4 and BA.5 appear to have particularly become more common in parts of the southern US, including Arkansas, Louisiana, New Mexico, Oklahoma, and Texas.