New COVID Variant: What To Know About KP.3

A new coronavirus variant is rising to dominance across the U.S. as experts are warning of a potential "summer wave" of COVID-19 cases.

Nicknamed "FLiRT," due to the positions of the mutations in their spike proteins, the new class of COVID subvariants has quickly spread through the U.S.

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In May, one of these new variants, named KP.2, took over as the most dominant strain of SARS-CoV-2 in America, according to the U.S. Centers for Disease Control and Prevention. However, since the beginning of June, a new FLiRT variant, named KP.3, has taken the lead and now represents 25 percent of COVID-19 cases in the U.S. KP.2 still follows as a close second, representing 22.5 percent of cases.

So should we be concerned about these new variants?

"Both KP.2 and KP.3 are descendants of the JN.1 subvariant [which was the major viral lineage circulating this previous winter] and belong to the FLiRT family of genetic changes," Adrian Esterman, an epidemiologist and professor of biostatistics at the University of South Australia, told Newsweek.

"They are very similar in terms of disease severity, and an ability to evade our immune systems.

"The difference between them is that KP.3 has an additional mutation called F456L, which is located in the spike protein. This mutation allows the virus to more easily latch on to our ACE2 receptors—this is called binding affinity—making it more infectious. This is why KP.3 is now starting to dominate."

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So what does this mean for vaccinations?

"Even though the FLiRT subvariants are now quite genetically distant from the XBB subvariants—the current vaccine is based on XBB.1.5—the vaccine will still give some cross-immunity against them," Esterman said.

"[However,] there will be a new vaccine available around September, based on either JN.1 or one of the FLiRT subvariants, that will give much better protection."

As for disease severity, Vanderbilt University's William Schaffner told Today that, from what we have seen so far, the new FLiRT variants do not generally cause severe disease. However, as we have seen over the last few years, viruses can change quickly.

At present, Schaffner said that the new variants are unlikely to cause "very distinctive symptoms."

According to the CDC, the main symptoms of COVID-19 to look out for are:

• Fever or chills
• Cough
• Shortness of breath
• Fatigue
• Muscle or body aches
• Headache
• Loss of taste or smell
• Sore throat
• Runny nose
• Nausea or vomiting
• Diarrhea

At present, CDC data suggests that, while COVID-19 infections are rising in the U.S., deaths and hospitalizations are down.

"We need to keep monitoring the spread of this variant," Lawrence Young, a virus expert and professor of molecular oncology at the U.K.'s University of Warwick, previously told Newsweek.

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Update 06/13/2024 05:05 a.m. ET: This article was updated to include exclusive comment from Professor Esterman.