(NEXSTAR) — It took just a few weeks for a new COVID variant to rank as the most prominent in the U.S., unseating its fellow ‘FLiRT’ spin-off of the once-dominant Omicron variant.

The latest projections from the Centers for Disease Control and Prevention show KP.3, a sublineage of the JN.1 lineage of the Omicron variant, may comprise 25% of the COVID tests sequenced in the country. Close behind is KP.2, which may make up about 22% of COVID cases.

CDC estimates for late May, the most recent available, show KP.3 may be most prevalent across states in the West and South. KP.2 is most common across the Midwest and Northeast. 

This comes after the CDC reported last week that COVID infections are believed to be “growing or likely growing in 30 states and territories.” In 18 others, cases are estimated to be “stable or uncertain,” while only one state — Oklahoma — is believed to be seeing a decline in cases.

While previous FLiRT variants KP.1.1 and KP.2 appear relatively similar to JN.1, experts have warned KP.3 may be better at evading immunity. However, KP.2 and KP.3 are still relatively similar, Dr. Natalie Thornburg, the chief lab official for the CDC’s Coronavirus and Other Respiratory Viruses Division explained last week.

When it comes to the symptoms the variants are sparking, officials say it’s too soon to tell if they’re causing anything unusual, like the increase in pink eye symptoms associated with XBB.1.16 reported last spring.

Speaking with TODAY, Dr. William Schaffner, a professor of infectious disease at Vanderbilt University Medical Center, said these FLiRT variants will likely not cause “very distinctive symptoms.” He added that these variants also don’t seem to cause severe cases.

The CDC lists the main symptoms of COVID as: 

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

However, the CDC notes these are not all of the possible symptoms of COVID as they can vary based on the person and the variant. 

A spokesperson for the agency tells USA Today that brain fog, or feeling less wakeful and aware, and upset stomach may also occur in patients with KP.3.

If you experience any COVID symptoms “that aren’t better explained by another cause,” the CDC recommends staying home and away from others. If you have risk factors for severe illness, experts recommend seeking medical care for testing and/or treatment.

Will COVID vaccines still protect you against the new variants?

Ultimately, it depends on when you got your last dose.

Previously, health officials have said the COVID vaccines would provide protection from the virus for “several months.” In a February update on the newest vaccine booster made available in September, the CDC said that while it had (from September to January) been effective, they expected that protection would “decline over time” as had been seen with previous doses. 

However, because the FLiRT variants are relatively new, there isn’t enough data to show whether the vaccine or immunity from a recent case of COVID will provide effective protection against them. 

Schaffner previously explained that lab studies have suggested that the vaccines will at least provide partial protection.

The newest COVID vaccine, expected to be released in fall, is set to target JN.1, an FDA panel determined last week. While it is not the most dominant variant in the U.S. anymore, annual vaccines are typically created based on a strain that closely relates to the most common variant at the time doses are being given.