(The Hill) – A new subvariant of the omicron variant of the coronavirus is becoming increasingly prevalent in the United States, according to data from the Centers for Disease Control and Prevention (CDC). 

CDC data shows that the BQ.1 and BQ.1.1 variants each made up 5.7% of the total number of cases in the country in the past week. The BA.5 subvariant, which has dominated the cases in the U.S. for months, made up 67.9%, down from its peak in late August when it made up almost 90% of all cases in the country. 

The BQ.1 and BQ.1.1 variants have increasingly spread in recent weeks, only trailing the BA.5 and BA.4.6 subvariants in making up the most cases. 

Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases and President Biden’s chief medical adviser, told CBS News in an interview that people need to “keep our eye out” for emerging variants despite cases and hospitalizations being down. 

“When you get variants like that, you look at what their rate of increase is as a relative proportion of the variants, and this has a pretty troublesome doubling time,” he said. 

Fauci said he is worried that subsequent variants may be more effective at evading medications that scientists have developed to help patients manage the virus. 

“That’s the reason why people are concerned about BQ.1.1, for the double reason of its doubling time and the fact that it seems to elude important monoclonal antibodies,” he said. 

Cases and hospitalizations have dropped since July, and deaths have been decreasing since August. But health officials have warned the public to expect an increase in cases as the winter approaches. 

The Food and Drug Administration has authorized an updated booster dose of Pfizer and Moderna’s COVID-19 vaccines to address the omicron subvariants. The booster is a bivalent vaccine, meaning it contains the mRNA vaccine for the original strain of the coronavirus and the vaccine for another strain. 

This booster is targeting the BA.4 and BA.5 subvariants.