New COVID-19 ‘FLiRT’ Variants Identified—What You Need to Know

 SARS-CoV-2, the virus that causes COVID-19, continues to mutate, with the latest crop of variants emerging just in time for summer. 

The newly identified group, dubbed “FLiRT,” includes a variant called KP.2, which the Centers for Disease Control and Prevention (CDC) lists as the dominant strain in the United States, accounting for 25% of new sequenced cases in the final two weeks of April. Another strain, KP.1.1, is less widespread, playing a role in 7.5% of cases during that time frame.1 

While COVID case rates in the U.S. are still relatively low overall, you might be wondering how concerned you should be about the debut of these new variants.

Here’s what you need to know about the FLiRT strains, including whether you can expect a COVID wave this summer.

What Are the FLiRT Variants? 

The FLiRT group of variants is named after the technical names of its mutations, F456L and R346T. They are part of SARS-CoV-2’s Omicron lineage, which was first detected in 2021.2

The new variants descend from JN.1, the primary variant circulating in the U.S. this past winter.3 That strain is now the second most dominant, accounting for 22% of cases.1

In April, the FLiRT strains quickly gained dominance. During the last week of March, only about 4% of COVID cases were caused by KP.2, compared to about a quarter just a few weeks later.3 

Do the FLiRT Variants Cause More Severe Illness?

Syra Madad, DHSc, MSc, senior director of the System-wide Special Pathogens Program at NYC Health + Hospitals and a fellow of Harvard University’s Belfer Center for Science and International Affairs, told Health that current data hasn’t shown “that the FLiRT variants are associated with increased severity of illness.”

However, she added, public health agencies are still learning about the new variants, so it’s too soon to know for sure whether they will cause more serious illness. “As public health continues to gather and analyze data on these variants, recommendations and public health guidelines may be updated to reflect new insights,” she said.

According to the CDC, the most common COVID symptoms include:4

• Fever
• Chills
• Cough
• Fatigue
• Loss of taste or smell
• Body aches
• Headaches
• Sore throat
• Congestion
• Nausea
• Diarrhea
• Shortness of breath

Do Vaccines Protect Against the New Variants?

The COVID vaccine should protect against the new strains. Still, preliminary evidence suggests that it may not offer as much protection against the FLiRT variants as it did against JN.1 this past winter.2 That’s because, compared to JN.1, the new variants are more distantly related to XBB 1.5, the strain targeted by the most recent COVID booster.

The good news is that the World Health Organization (WHO) has recommended that future COVID vaccine formulations be based on JN.1, which is more closely related to the FLiRT variants