It was just last winter that the highly-transmissible Omicron variant co-opted the holiday season and sent COVID-19 cases soaring well into the new year. But what should we prepare for this time around? Here's everything you need to know:
Should we expect a winter COVID wave?
Public health experts are certainly worried, especially considering the rising case counts in the U.K. and across Europe, The Scientist reports. "In the past, what's happened in Europe often has been a harbinger for what's about to happen in the United States," Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told NPR at the beginning of October. "So I think the bottom line message for us in this country is: We have to be prepared for what they are beginning to see in Europe."
Given widespread immunity following the BA.5 Omicron variant surge, mid-August forecasts from the so-called COVID-19 Scenario Modeling Hub suggested "the United States could be in for a relatively quiet COVID-19 season ... as long as vaccine-booster campaigns began quickly and new variants didn't emerge," Nature reports. But it's also not yet clear if the European "surge" is a result of "behavioral changes and climate," like colder weather pushing gatherings indoors where the virus is more likely to spread, or something more sinister, Justin Lessler, an epidemiologist involved with the modeling hub, told NPR. If the former, Lessler said, the U.S. "might be able to avoid similar upticks if there is broad uptake of the bivalent vaccine." But if it's the latter, something like "immune escape across several variants with convergent evolution, the outlook for the U.S. may be more concerning."
And Americans haven't exactly been running to get their new bivalent boosters: As of Oct. 28, just 22.8 million people over the age of 5 — 7.3 percent of the U.S. population — had received their updated combination dose, according to the Centers for Disease Control and Prevention. Meanwhile, new immune-evading "Omicron offshoots," like BQ. 1, BQ.1.1, and XBB, have been gaining traction globally, and will very likely soon take center stage in the U.S. And though weekly cases have been on the decline since July (despite a slight uptick in the week ending Oct. 26), the levels of virus circulating in wastewater in Northeastern states like Pennsylvania and Vermont also suggest a surge is imminent, per NPR and Time.
Separately, an analysis from the University of Washington estimates "far fewer infections ... than last winter's estimated peak daily average," but predicts global cases will still "rise slowly to about 18.7 million by February from the current 16.7 million average daily cases, driven by the northern hemisphere's winter months," Reuters summarizes. On the upside, the increase in cases is not expected to cause a surge in deaths, per the analysis.
Speaking of new variants ... what are they?
Unlike variants past, the latest strains of concern aren't that of a new Greek letter, The Washington Post reports. Rather, they're a "group of immune-evading Omicron spinoffs ... popping up all over the world." Each represents a different "flavor" of the virus, "adorned with a similar combination of mutations" that, most concerningly, appears consistently successful in blocking humans' main line of immune defense. Perhaps most adept at doing so is the XBB variant, a strain formed from a combination of Omicron subvariants B.A.2.75 and BA.2, according to the Japan Times. XBB only recently arrived in the U.S. after tearing through the largely vaccinated Singapore, per The New York Times.
Otherwise, U.S. health officials have said they're "very carefully" monitoring emergent subvariants BQ.1 and BQ.1.1, the San Francisco Chronicle reports. The two strains are "our greatest concern right now, both for the number of mutations, but also for the impact and the phenotype that we are worried that they may imply," CDC Director Dr. Rochelle Walensky said recently. Taken together, BQ.1 and BQ.1.1 made up 27.1 percent of U.S. cases as of Oct. 28 for the week ending Oct. 29, per the CDC's tracker. The subvariants do not seem to cause more severe illness than their parent strain BA.5, but they are more transmissible.
According to Dr. Anthony Fauci, Biden's chief medical adviser, the country is "certainly in a better place than we were many months ago," but "we need to watch and follow these things very carefully, because we want to make sure we have a good handle on what is going on with regard to the emergence of variants, and what impact they're going to have on any trends we are going to see in winter," per the Post.
What is the "tripledemic"?
When taken alongside the rise in flu and RSV cases (RSV being a respiratory virus for which kids are especially prone), White House officials fear a winter COVID surge could give way to a so-called "tripledemic" — or a "nasty collision" of all three viruses, the Times reports. Per WebMD, children's hospitals are already seeing a surge in pediatric RSV cases, while flu season, meanwhile, is "off to an early start."
The surge in the three viruses "is almost predictable at this point in the pandemic," Dean Blumberg, MD, of the University of California Davis Health, told WebMD. "All the respiratory viruses are out of whack."
What can I do to protect myself from COVID and the "tripledemic" this winter?
First and foremost, get vaccinated for both the flu and COVID-19. Even if you get infected, the bivalent booster and/or primary series of COVID vaccinations will protect you from serious disease and death. Wash your hands often, and always stay home from work or school if you're feeling sick. Wear a mask if you can.
If you're relatively healthy, "none of those viruses is a big threat to you necessarily," explained the Times' Apoorva Mandavilli, but they are "a threat to our health care system, which is already so stretched." So do your part to ensure hospitals remain accessible for those most vulnerable to COVID and the "tripledemic," like children, pregnant people, and the elderly. "The boosting is the thing that has to get buckled down," cardiologist Dr. Eric Topol told the Times. "As a nation, we are terribly under-boosted."
"We need everyone to step up," added White House COVID-19 Response Coordinator Ashish Jha. "This is literally about saving lives of tens of thousands of Americans this fall and winter," and "[t]he great news here is that, unlike past winters, we are in control."