The news comes as the organization warns of the yet unknown dangers of repeat COVID infection, which can occur without symptoms.

Because most people have some immunity to COVID due to vaccination and/or prior infection, “we don’t necessarily know how often we’re getting infected,” Dr. Maria Van Kerkhove, head of WHO’s emerging diseases and zoonoses unit, said at a news briefing in Geneva.

“Five years, 10 years, 20 years from now, what are we going to see in terms of cardiac impairment, pulmonary impairment, neurologic impairment? It’s year five in the pandemic, but there’s still a lot we don’t know about it.”

The concerns regarding COVID infection are multipronged, she said, and include potential acute implications like hospitalization and death, the development of long COVID, and “even longer-term effects” like those she referenced.

It’s estimated that 6% to 10% of those infected with COVID will go on to develop long COVID, she added.

“It’s real,” she said of the condition. “It’s not in someone’s head. This is actually a real condition that needs to be studied properly.”

The pandemic continues

Whether we acknowledge it or not, the world is still in a pandemic, Van Kerkhove said, citing the virus’s lack of a seasonal pattern, which many respiratory pathogens have, and its continued, rapid-pace evolution.

What’s more, hundreds of thousands around the world are currently hospitalized with the virus, and around 10,000 died from it last month, she said—likely untold more. COVID hospitalizations and ICU admissions rose by 42% and 62%, respectively, in December.

This world is currently experiencing a surge of JN.1, a highly mutated Omicron spawn some say deserves a new Greek letter from the WHO, like Pi or Rho. In the U.S., it’s currently fueling the country’s second-largest wave of the pandemic.

COVID’s ongoing impact remains underappreciated, Van Kerkhove said. Death figures are based on data from only 50 countries and territories still reporting to the WHO, out of 234, she said. Hospitalization figures come from only 29. And only 21—less than 9%—still report ICU data.

Of the 10,000 COVID deaths reported to the WHO in December, “more than half were from the U.S., and 1,000 were from Italy,” she added. “We are missing deaths in countries from around the world. Just because countries aren’t reporting deaths doesn’t mean they’re not happening.”

Because so many countries are failing to report their data but some still produce and publish reports, “unfortunately, we’re back to sort of scraping the Web, finding each report, and adding them to our dashboard,” she said.

As of Dec. 31, the pandemic’s official death count sat at 7 million. But the true total is likely at least three times higher, she said.

In the near term, at least, hospitalizations and ICU admissions should still rise due to viral transmission during recent holiday gatherings. The WHO fears that COVID—when combined with other seasonal respiratory pathogens like the flu, RSV, parainfluenzas, and the like, and infections from bacteria like mycoplasma pneumoniae—places “far too much burden on countries.” Much of the burden, however, could be prevented with mitigation measures like vaccination, according to Van Kerkhove.

A more severe variant still possible

When queried about studies published in the journal Cell this week that pointed to the potential for more severe disease from highly mutated variant BA.2.86—”parent” of the globally dominant variant JN.1—Van Kerkhove said that the WHO had seen the data before it issued its risk assessment about BA.2.86 in November. That risk assessment said the variant posed a “low” global risk.

The studies were based on pseudoviruses, or lab-created versions of the virus, she pointed out. Viruses sometimes behave differently in the real world, when met with factors like existing population immunity and human behavior.

“We don’t have any indication in people that there’s a change in severity for JN.1,” she said. While hospitalizations and deaths are rising, experts are unclear on whether it’s due to the severity of a particular variant or waning population immunity, which begins to decline three to six months after infection or vaccination, on average.

Still, the world isn’t prepared for a more severe variant of the virus, should one evolve, because countries no longer see COVID as a global threat, she said. Consequently, there’s no agility to “scale up and scale down” the flow of tests, antivirals, medical oxygen, and other necessary supplies.

“We are concerned—deeply concerned—that this virus is circulating unchecked around the world, and that we could have a variant at any time that would increase severity,” she said. “This is not meant to be a scare tactic. This is a scenario we plan for.”

The WHO’s Technical Advisory Group on SARS-CoV-2 Virus Evolution (TAG-VE)—in charge of designating variants of concern and assigning Greek letters—meets again Monday, she added.

In an exclusive interview Dec. 30, Van Kerkhove told Fortune that the WHO is ready to assign a new Greek letter on a moment’s notice if necessary. But the organization is holding out for a variant that is “truly different,” she said at the time—one that impacts public health.

“If we were to see any change in severity, for example, we wouldn’t hesitate to call this a VOC, or the next one a VOC,” she said. “But phenotypically, we’re really seeing similar behavior to the other circulating variants.”

TAG-VE is devising a new variant classification system it hopes to debut later this year, Van Kerkhove said. It’s discussing various ways to group variants, taking into account how genetically similar they are, which key mutations they possess, and the symptoms they cause.

But for now, labeling variants the WHO deems concerning as VOCs—something the organization hasn’t done since November 2021—works “really well, should there be something that is really, really different, really severe,” she said.

“If we were to see a variant that fell within our classification of a VOC, we would call it in a day,” she added. “We would do that immediately, no hesitation whatsoever… Just because we’re not giving it a name does not mean it’s not a threat.”