While the omicron subvariant BA.5 has been the dominant strain of COVID in the United States for several months, there are at least four other subvariants starting to gain ground in recent weeks.
According to the latest estimates released by the CDC on Tuesday, the BA.5 subvariant is still responsible for 84.8% of COVID cases in the United States.
That subvariant, which has been the dominant strain of COVID in the U.S. since early July, peaked at nearly 90% of cases at one point, but has slowly begun to decline as at least four other types of omicron begin to circulate in the population.
One of those strains, the BA.4.6 subvariant, is now responsible for more than 10% of COVID cases in the United States for the first time. The subvariant, which has been circulating since at least early June, now makes up 10.3% of cases, and is slowly beginning to gain steam as it’s parent strain BA.4 continues to decline.
That BA.4 subvariant is still the third-most common in the U.S., responsible for an estimated 1.8% of cases, but two other subvariants are now being tracked by the CDC as they keep a wary eye on the development of new strains ahead of the fall and winter months.
The BF.7 subvariant is actually a sublineage of BA.5, according to the CDC. Its official name is BA.220.127.116.11, but scientists have instead shortened it to BF.7 in reporting documents.
Scientists are continuing to keep a close eye on that subvariant, responsible for 1.7% of cases, because it has now surpassed another sublineage of omicron, BA.2.75, in terms of cases at this time.
According to Fortune magazine, Belgium is currently seeing a surge in BF.7 cases, as are Denmark, Germany and France.
Scientists are also keeping an eye on whether the BF.7 subvariant behaves any differently than BA.5, but all omicron strains have shared similar characteristics, showing increased ability to maneuver around preexisting immunity from earlier infections and an increased ability to avoid immunity conveyed by vaccines.
It is not known at this time how effective the new bivalent COVID vaccines, which were specifically formulated to target omicron subvariants, will be against BF.7.