New COVID-19 variant accounts for more than a quarter of cases
Dani Blum
For most of this year, the JN.1 variant of the coronavirus accounted for an overwhelming majority of COVID-19 cases. But now an offshoot variant called KP.2 is taking off. The variant, which made up just 1% of cases in the United States in mid-March, now makes up more than one-quarter.
KP.2 belongs to a subset of COVID variants that scientists have nicknamed “FLiRT,” drawn from the letters in the names of their mutations. They are descendants of JN.1, and KP.2 is “very, very close” to JN.1, said Dr. David Ho, a virus expert at Columbia University. But lab tests suggest that slight differences in KP.2’s spike protein might make it better at evading our immune defenses and slightly more infectious than JN.1, Ho said.
While cases don’t appear to be rising, researchers and physicians are closely watching whether the variant will drive a summer surge.
“I don’t think anybody’s expecting things to change abruptly, necessarily,” said Dr. Marc Sala, co-director of the Northwestern Medicine Comprehensive COVID-19 Center in Chicago. But KP.2 will most likely “be our new norm,’” he said.
Here’s what to know.
The current spread of COVID
Experts said it would take several weeks to see whether KP.2 might lead to a rise in cases and noted that we have only a limited understanding of how the virus is spreading. Since the public health emergency ended, there is less robust data available, and doctors said fewer people are using COVID tests.
But what we do know is reassuring: Despite the shift in variants, data from the Centers for Disease Control and Prevention suggests there are only “minimal” levels of the virus circulating in wastewater nationally, and ER visits and hospitalizations fell between early March and late April.
Protection from vaccines
Experts said that even if you had JN.1, you may still get reinfected with KP.2, particularly if it’s been several months or longer since your last bout of COVID.
KP.2 could infect even people who got the most updated vaccine, Ho said, since that shot targets XBB.1.5, a variant that is notably different from JN.1 and its descendants. An early version of a paper released in April by researchers in Japan suggested that KP.2 might be more adept than JN.1 at infecting people who received the most recent COVID vaccine. (The research has not yet been peer-reviewed or published.) A spokesperson for the CDC said the agency was continuing to monitor how vaccines perform against KP.2.
Still, the shot does provide some protection, especially against severe disease, doctors said. People age 65 and older, pregnant or immunocompromised remain at higher risk of serious complications. Those groups may want to get the updated vaccine if they haven’t yet, said Dr. Peter Chin-Hong, an infectious disease specialist at the University of California. The CDC recommends that people 65 and older who already received one dose of the updated vaccine get an additional shot at least four months later.
“Even though it’s the lowest level of deaths and hospitalizations we’ve seen, I’m still taking care of sick people with COVID,” he said. “And they all have one unifying theme, which is that they’re older and they didn’t get the latest shot.”
Similar symptoms
Doctors said the symptoms of both KP.2 and JN.1, which now makes up around 16% of cases, are similar to those of other variants. These include sore throat, runny nose, coughing, head and body aches, fever, congestion, fatigue and, in severe cases, shortness of breath.
Fewer people lose their sense of taste and smell now than did at the start of the pandemic, but some people will still experience those symptoms.
Chin-Hong said that patients were often surprised that diarrhea, nausea and vomiting could be COVID symptoms.