Two new omicron subvariants have surpassed BA.5 as the dominant versions of the coronavirus in the United States
BA.5 became dominant in July and then still accounted for the majority of new Covid infections until last week.
But data from the Centers for Disease Control and Prevention released on Friday showed that the new subvariants – called BQ.1.1 and BQ.1 – took over. The two together account for around 44% of new Covid infections, while BA.5 only accounts for 30%.
“The BA.5 is essentially declining rapidly, likely gone soon,” said Dr. Dan Barouch, director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston.
BQ.1.1 and BQ.1 cases are also increasing in the UK and elsewhere in Europe. The two subvariants accounted for about 18% of new infections in the European Union from October 17 to 30, and the European CDC expects that share to increase to more than 50% this month or next.
Both sub-variants are considered part of the BA.5 family – these are sub-lines that evolved from BA.5. But preliminary data suggests they are better at evading immunity from Covid vaccines, including new bivalent boosters, or previous Covid infection than earlier versions of omicron. This may give these subvariants higher transmissibility, which could fuel an increase in cases this winter.
Research by Dr. Shan-Lu Liu, co-director of the Emerging Viruses and Pathogens Program at The Ohio State University, suggests that BQ.1.1 and BQ.1 both have a mutation that makes them better able to enter our cells. Liu’s findings are expected to be published in the journal Cell Host & Microbe, but a non-peer-reviewed version is available online.
“There is a clear trend for these two new subvariants to take off, which is concerning,” he said, noting that the share of BQ.1.1 and BQ.1 infections in the United States has slightly increased. nearly doubled every week since early October.
Barouch said BQ.1.1 in particular has an additional mutation that may make it slightly better at avoiding antibodies than BQ.1. For this reason, he predicts that BQ.1.1 will overtake its sibling and cause “a large amount of infections” this winter.
“BQ.1.1 appears to be the most elusive antibody variant we’ve seen to date,” Barouch said.
He published preliminary findings this month showing that Covid vaccines (both original versions and updated boosters) do not resist BQ.1.1 as well. The data has not been peer-reviewed, but the results suggest that people who received updated boosters or original vaccines from Moderna or Pfizer had about seven times lower antibody levels against BQ.1.1 than against BA.5.
However, because these BQ subvariants are genetically similar to BA.5, vaccines, tests and treatments should still work against them overall, said Johns Hopkins University virologist Andrew Pekosz.
“In the United States right now, virtually all of the circulating variants are related to BA.5, and so if you get the bivalent vaccine, you’ll boost your immunity to some degree,” Pekosz said.
Nor do scientists expect these new subvariants to cause more severe disease.
“It’s encouraging that we’re not seeing very large increases in hospitalizations, because it implies that the immunity we have is still protecting us against serious disease,” Pekosz said.
So far, Covid symptoms have remained relatively constant across all omicron variants. Data from the Zoe COVID Symptom Study, which allows people in the UK to self-report their symptoms via a smartphone app, suggests that sore throat, congestion, headache, cough and runny nose were the main symptoms of Covid in early November.
“There is nothing in the signature of the reported clinical cases to suggest that anything changes in terms of symptoms with these omicron subvariants,” Pekosz said.
But the rise in new subvariants could be a sign that the United States is experiencing a rise in Covid cases that is not reflected in official data, he added. Many people use home tests, but the CDC does not track these results unless they are confirmed by a health care provider.
“What we can see here is that there are probably a lot more infections than we’re counting, and so the virus had a lot more opportunity to mutate,” Pekosz said.
He added that it is not yet clear whether BQ.1.1 and BQ.1 will remain dominant for long. Scientists are also monitoring XBB, another omicron subvariant from the BA.2 strain that may be even better than the BQ subvariants at evading antibody protection. XBB circulates more widely in Asia than in the United States
As the holidays approach, some virologists predict the United States could see a new surge of cases as more people travel and congregate indoors.
“Last year around Thanksgiving, omicron came out of nowhere,” Liu said. “It’s a virus. Anything can happen.”