While the BA.5 variant of COVID-19 continues to make up the majority of cases in the United States, several recent variants are beginning to emerge in larger numbers, causing concern among health officials.
With colder weather on the way in the coming months, here's what we know about the recently emerging variants as the COVID-19 pandemic heads into its third winter:
What Are The New Variants?
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BQ.1.1 and BQ.1 are among the newer variants to emerge but are already rising above other recent variants in their spread, according to the CDC.
According to Fortune, XBB was first detected in the U.S. on Sept. 15. It is not yet widespread, as only 16 cases have been reported here, mostly in New York.
The CDC's latest update on the prevalence of COVID variants shows no signs of XBB yet in New England, as BA.5, BA.4.6 and the new BQ.1.1 and BQ.1 variants continue to dominate. But throughout the pandemic, COVID numbers in New York have often provided an early look at what Massachusetts and the other southern New England states have in store.
What Other Countries Have Been Affected Already?
One variant that has yet to show up in sizable numbers in the U.S., the XBB variant, has been making headlines for its role in a recent wave of COVID cases in Singapore.
"The XBB variant wave in Singapore will soon be their 2nd worst for the pandemic," Dr. Eric Topol, founder of the Scripps Research Translational Institute, recently tweeted. "The reinfection rate prior to the wave was 5% and now up to 17%, which tells us about the immune escape properties of this variant (akin to BQ.1.1, very high level of immune evasion)"'
Dr. Maria Van Kerkhove, an infectious disease specialist who serves as the technical lead for COVID-19 response at the World Health Organization, addressed growing concerns about the XBB variant in a Twitter video last week. She said XBB is a "recombinant" of two BA.2 sublineages, BA.2.10.1 and BA.2.10.75.
"We do know this recombinant has a significant growth advantage. All of the subvariants of omicron are showing increased transmissibility and properties of immune escape," she said. "With this XBB recombinant we have one study based on a pseudo virus, so not a live virus, that is analyzing antibody escape and it's showing significant immune evasion. And this is of concern for us because we need to ensure that the vaccines that are in use worldwide will remain effective at preventing severe disease and death."
Van Kerkhove said there have been no signs of increased severity in XBB and BQ.1.1 and BQ.1 variants, "but it's very early and we have very little data to assess this."
"We need to be prepared for this," she said. "Countries need to be in a position to conduct surveillance, deal with increases in cases and perhaps deal with an increase in hospitalizations. We don't see a change in severity yet and our vaccines remain effective, but we have to remain vigilant."
Could the New Variants Better Evade Vaccines and Treatments?
A major concern is whether the new variants can evade treatment from monoclonal antibodies, like Evusheld, which is used to prevent infections in those who are immunocompromised and not generating enough response from the vaccine.
The U.S. Food and Drug Administration earlier this month updated its information for health care providers to state that those receiving the treatment could be at an "increased risk for developing COVID-19 when exposed to variants of SARS-CoV-2 that are not neutralized by Evusheld."
According to White House Medical Adviser Dr. Anthony Fauci, BQ.1.1 specifically has shown an “apparent ability to evade antibody treatments,” such as monoclonal antibodies, and says that the variants are showing "pretty troublesome" characteristics.
“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 told CBS in an interview.
According to NPR, "doubling-time" is a metric used by epidemiologists to determine how rapidly a virus is spreading in a given population. The faster that cases of a particular strain double, the faster it is spreading, according to physicians.
Are the New Bivalent Boosters Still Effective Against These Variants?
Fauci did say that while all data is preliminary, it does appear that the new bivalent COVID boosters, specifically formulated to combat omicron subvariants, are still effective at preventing serious illness and death even with the new variants that are emerging.
The White House last week said eligible Americans should get the updated COVID-19 boosters by Halloween to have maximum protection against the coronavirus by Thanksgiving and the holidays, as it warned of a “challenging” virus season ahead.
Dr. Ashish Jha, the White House COVID-19 coordinator, said the U.S. has the tools, both from vaccines and treatments, to largely eliminate serious illness and death from the virus, but stressed that's only the case if people do their part.
“We are not helpless against these challenges," he said. “What happens this winter is up to us.”
Still, it remains unclear whether those new bivalent boosters will protect against infection in general, with studies still underway even as Americans get the shots.
Germany's health minister warned at the end of September that the country is seeing a steady rise in COVID-19 cases as it goes into the fall, and urged older people to get the new COVID booster shots. Other European countries such as France, Denmark and the Netherlands are also recording an increase in cases, Karl Lauterbach told reporters in Berlin.
“We are clearly at the start of a winter wave,” he said.
This comes as cases, deaths and hospitalizations continue to decrease across the United States, according to CDC data.
Even still, Fauci and other public health officials say that slow uptake of the new COVID vaccine boosters could potentially lead to serious consequences in the fall and winter months, when more residents are spending time indoors.
This week's Massachusetts coronavirus case numbers actually saw a slight decrease from the previous week, and wastewater data is not showing any increase at this time. But the COVID risk levels assessed by the Centers for Disease Control and Prevention have seen an uptick across the region in recent weeks.
All of Massachusetts was in the CDC's low risk category just a month and a half ago, but the entire state is now considered medium risk.
Despite vaccine uptake, doctors interviewed by NBC10 Boston this week said they still anticipate a surge in the coming months.
"Only time will tell," Dr. Sabrina Assoumou of Boston Medical Center said. "My big message is, unfortunately, we're seeing more variants, and the virus is actually figuring out better ways to evade our protection, but we're not hopeless and it's not a helpless situation. We have vaccines, they actually work, but the key thing is that you have to be up to date... So please get get up to date so that we are all prepared in the community before a potential winter surge."
"I think it's likely that we'll continue to see the proportion of cases that are being caused by the new variants increase because they do seem to be able to evade immunity," added Dr. Daniel Kuritzkes of Brigham and Women's Hospital. "But for the general public. I think the issue is going to be that, first of all, receiving a booster vaccine, as Dr. Assoumou said, will strengthen immunity because even if this variant can get around the antibodies and may get people infected and give them a cold, they're not going to have anything much worse than an upper respiratory infection if they've been recently boosted because there does seem to be much broader cross protection across all of these variants for severe disease and that's a really important point.