On Wednesday the World Health Organization designated EG.5 a “variant of interest” due to its steady global growth, upgrading it from the less concerning category of “variant under monitoring.” Reports of EG.5, detected in 45 countries so far, nearly doubled from mid-June through mid-July, according to an Aug. 3 WHO situation report. 

While genetic sequencing and reporting is at an all-time low, the largest number of EG.5 samples so far have come from China, according to a WHO risk evaluation published Wednesday. The U.S., Korea, Japan, Canada, the U.K., France, Singapore, Australia, Portugal, and Spain have all reported at least 100 cases, according to the report.

The global risk posed by EG.5 is low and similar to the two other circulating variants of interest: XBB.1.5 and XBB.1.16, according to the WHO. No changes in disease severity have been reported. But because of the variant family’s increased ability to spread and escape antibody immunity, “EG.5 may cause a rise in case incidence and become dominant in some countries or even globally,” the agency stated.

EG.5 cases and hospitalizations are on the rise in Japan and Korea, the WHO said. But it’s unknown if the two trends are connected.

U.S. COVID trends

In the U.S., EG.5 and its spinoffs are now the most common COVID variants, according to the latest projections issued by the U.S. Centers for Disease Control and Prevention. The viral family was estimated to account for 17.3% of cases in the country as of Friday. Meanwhile, COVID hospitalizations have risen nearly 13% over the past two weeks, according to CDC data. And levels of the virus in wastewater have already crested into a half-wave, albeit a relatively small one.

Experts are keeping their eye on EG.5 “child” variant EG.5.1 (dubbed Eris by variant trackers, after the second-largest known dwarf planet in the solar system). EG.5.1 is taking off in the U.S.—it’s responsible for nearly 8.5% of sequenced cases over the past three weeks, according to GISAID, an international research organization that tracks changes in COVID and the flu virus. Levels are also rising in Europe and Asia, Dr. Eric Topol, a professor of molecular medicine at Scripps Research and founder and director of the Scripps Research Translational Institute, wrote in a Sunday blog entry.

With testing and sequencing at all-time lows, it’s impossible to say for certain whether EG.5.1 is fueling the current rise in cases in the U.S. and abroad. But “it certainly does not look benign,” Topol wrote.

Some locations like New York City “are already seeing upticks in the number of COVID-19 cases, and we should expect that we might see similar increases in cases in other parts of the country,” Talia Quandelacy, assistant professor of epidemiology at the Colorado School of Public Health and a member of the state’s COVID modeling group, told Fortune.

“We could see COVID-19 cases increasing around the same time as flu season (October to May) if we don’t see cases increasing earlier from a new variant,” she added.

Symptom-wise, it’s too early to say if EG.5.1 is any different from other Omicron strains. And the variant may not cause a large wave of cases, according to Ryan Gregory, a biology professor at the University of Guelph in Ontario. He’s been assigning “street names” to high-flying variants since the WHO stopped assigning new Greek letters to them.

“My best guess is we’re heading back up to a high baseline [of cases] that may stay up there, but probably not a huge wave,” he tells Fortune. “The past year has been about rising sea level, not tsunamis.”

A look ahead to new boosters

Updated COVID boosters targeting the XBB.1.5 strain—which may not be ready until late September, according to reports—should still work against EG.5 and related variants, experts say. The CDC has yet to issue recommendations as to who should get the new jab and when.

Topol is concerned about the impact of delayed distribution on those who are immunocompromised and elderly. For them, especially, it’s not ideal that the only booster available—the Omicron BA.4/BA.5 booster, released around Labor Day last year to match strains that peaked earlier that year—isn’t as closely matched to currently circulating strains as the new booster is.

If new boosters were “coming out imminently next week, or by the end of the month, that would be okay,” he said. “But if you wait until September, October, schools are starting. By then we’re already seeing wastewater levels rise. We have a wave that’s brewing now.”

Gregory and Raj Rajnarayanan—assistant dean of research and associate professor at the New York Institute of Technology campus in Jonesboro, Ark., and a top COVID-variant tracker—worry that many, if not most, Americans will choose to forgo the new jabs. It’s thought that only 27% of adults and 18.5% of adolescents had received an Omicron booster as of late last year, according to a survey conducted by the CDC. 

With the pandemic emergency state officially over, according to the WHO and CDC, even fewer might this time around.

“I don’t think people will line up to take the vaccines,” Rajnarayanan said.