Two new versions of omicron are gaining ground in U.S., the CDC estimates
The omicron subvariants known as BA.4 and BA.5 now represent 13% of new coronavirus cases in the United States, up from 7.5% a week ago and 1% in early May, according to new estimates from the Centers for Disease Control and Prevention.
The spread of the subvariants adds more uncertainty to the trajectory of the pandemic in the United States, where current case counts are likely to be a significant underestimate. But whether it leads to a major new wave of infections, or spikes in hospitalizations and deaths, remains unclear, scientists cautioned.
The new figures, which were released Tuesday, are based on modeling, and the CDC’s estimates have missed the mark before. But the overall trend suggests that BA.4 and BA.5 could outcompete the two other omicron subvariants, BA.2 and BA.2.12.1, which together account for most U.S. cases, said Denis Nash, a public health researcher at the City University of New York Graduate School of Public Health & Health Policy.
“This could happen very quickly,” Nash said.