The COVID "FLiRT" Symptoms You Need to Know About

  • There are several COVID variants right now which have the same "set of mutations," and are being referred to as FLiRT.

  • KP.2 — which comes from the JN.1 strain — is now the most dominant variant, accounting for 28% of cases.

  • The symptoms are similar to other COVID strains. Being sick and experiencing a chronic cough, elevated fever, sore throat or a runny nose should prompt you to get a COVID-19 test to ensure you are not contagious.

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Move over, JN.1. There’s a new COVID-19 variant in town.

The latest report from the Centers for Disease Control (CDC) published on May 11th, revealed that FLiRT has become the dominant strain quickly spreading across the United States. The CDC estimates that it currently accounts for 28.2% of cases, up from 15.9% just two weeks ago when the previous report was released on April 27th. Meanwhile, the formerly dominant variant JN.1 fell from an estimated 28.2% of all coronavirus cases to 15.7% during the same two-week period.

“The FLiRT variant appeared in March,” says Tammy Lundstrom, MD, JD, the senior vice president at Trinity Health who led their COVID-19 response. “Throughout the COVID-19 era, new strains have continued to arise. Like other strains, it appears highly transmissible, but it does not appear more virulent at this point.”

However, since just 22.5% of American adults have received a COVID-19 vaccine since September 2023, it’s no wonder that the new dominant variant went from accounting for an estimated 1.4% of new cases on March 16th to 6.4% of cases on April 13th to more than quadrupling (a 341% increase) in less than a month. But what does this mean for COVID-19 infections during summer? We spoke with experts to explain the new variant, symptoms to watch out for and how to protect yourself and your loved ones from the latest SARS‑CoV‑2 virus variant.

What is the FLiRT variant?

As fun as the name sounds, FLiRT is not the official designation for the dominant COVID-19 variant. That is actually a cheeky nickname for a whole family of different variants (any that start with KP or JN). “The FLiRT variants came to the forefront at the end of April,” says Nikhil K. Bhayani, MD, FIDSA, an infectious disease specialist and assistant professor at the Burnett School of Medicine at Texas Christian University. “One variant in particular has risen to prominence: KP.2.”

KP.2 is the official name of the variant mentioned above that has unseated JN.1 as the dominant strain. However, the FLiRT variants are all descendants of the JN.1 variant — meaning the “parent” variant (JN.1) is being unseated by several “child” variants. Although KP.2 is quickly becoming the dominant strain of COVID-19, JN.1.7 currently accounts for an estimated 13.3% of new cases, while JN.1.16 is responsible for 10%, JN.1.13.1 accounts for 8% and KP.1.1 accounts for 7.1% of growing infections. Meanwhile, the “grandparent” variant BA.2.86, from which JN.1 mutated and which itself is a subvariant of Omicron, is listed at an estimated 0% of cases, according to the CDC.

What are the symptoms?

The good news is that KP.2 doesn’t seem to spark any surprise symptoms. “The symptoms are similar to other COVID-19 strains,” says Dr. Lundstrom. The CDC updated its list of possible symptoms in March, and those include:

  • Fever or chills

  • Cough

  • Shortness of breath or difficulty breathing

  • Fatigue

  • Muscle or body aches

  • Headache

  • New loss of taste or smell

  • Sore throat

  • Congestion or runny nose

  • Nausea or vomiting

  • Diarrhea

“Like similar recent strains, the incidence of loss of taste and smell are not prominent," adds Lundstrom.

Do we need to worry about a summer surge?

The wastewater viral activity for COVID-19 — how the CDC tracks trends in infectious disease circulating in a community — is currently listed as “minimal,” according to CDC data from May 4th. The CDC itself says on X that KP.2 “isn’t causing an increase in COVID-19 infections or more severe illness than other variants.”

Dr. Bhayani says that it’s “too early to tell how contagious this variant is” but that we “might see an increase in COVID-19 cases this summer due to the fact that this is a new variant which few people have been exposed to.”

Meanwhile, Dr. Lundstrom says that “there is a concern that this new variant could fuel a summer surge in cases,” and that “throughout the COVID-19 era, we have seen a rise in infections during summer.” However, “COVID-19 infections and hospitalizations are declining” overall.

Is there a new vaccine?

Our experts said that vaccines still provide good protection against COVID-19, “especially against severe illness and hospitalization,” says Lundstrom. However, a study published in April found that KP.2 is proving to have “the most significant resistance” to the 2023-24 COVID-19 booster, and that this “increased immune resistance ability of KP.2 partially contributes to the higher” prevalence of infections “than previous variants, including JN.1”

“The current vaccine was directed to XBB strains,” Lundstrom continues. “The FDA and CDC will meet in early June to determine which strains should be included in the fall vaccine, and who should get vaccinated in the fall.”

“The World Health Organization is recommending the upcoming COVID booster to be based on the predominant lineage for the year,” adds Dr. Bhayani.

However, the CDC and our experts still recommend the current vaccine to protect yourself before the 2024-25 booster is made available in the fall. “Adults over the age of 65 should get the last COVID-19 vaccine available,” says Bhayani. Dr. Lundstrom suggests that older adults “should be vaccinated four months after their last vaccination” and those with compromised immune systems “should get vaccinated two months after their last dose.”

How to protect yourself

In March, the CDC updated the Respiratory Virus Guidance as COVID-19 cases have decreased over time. “It is still an important health threat, but it is no longer the emergency that it once was, and its health impacts increasingly resemble those of other respiratory viral illnesses, including flu and RSV,” the new guidance states.

“The same precautions will help protect against the spread of most respiratory viruses: wash hands frequently, cover your mouth and nose when sneezing/coughing, stay up to date with vaccinations and stay home when ill to prevent spreading infection to others,” suggests Dr. Lundstrom. However, Dr. Bhayani reminds us that the elderly, individuals with compromised immune systems, and kids “should take extra precautions, such as avoiding large crowds and wear masks if COVID-19 cases are on the rise locally.”

If you do get sick, the CDC still recommends staying at home until your symptoms are improving overall, and you have not had a fever (and are not using fever-reducing medication). Afterward, you can resume normal activities and “use added prevention strategies over the next five days.”

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