New COVID ‘FLiRT’ variants are spreading nationwide

A new family of COVID variants nicknamed “FLiRT” is spreading across the country, as vaccination rates nationwide remain worryingly low for some public health experts.

While symptoms and severity seem to be about the same as previous COVID strains, the new FLiRT variants appear to be more transmissible, said infectious-disease expert Dr. Robert Murphy.

“A new, more contagious variant is out there,” said Murphy, the executive director of Northwestern

University’s Institute for Global Health and a professor of infectious diseases at the Feinberg School of Medicine. “COVID-19 is still with us, and compared to flu and RSV, COVID-19 can cause significant problems off-season.”

The name “FLiRT” is an acronym using the technical names for the mutations that caused the family of variants.

Murphy urged the public, particularly individuals who are at higher risk for severe complications from the virus, to get up to date on COVID shots. While much of the population has some immunity from vaccination or previous COVID infections, Murphy noted that “with COVID-19, immunity wanes over time.”

One FLiRT variant, KP.2, is estimated to account for roughly a quarter of recent COVID cases, according to Centers for Disease Control and Prevention data from late April.

That means it has outpaced the previously most common strain, JN.1, which spurred much of the winter respiratory season’s spike in COVID cases and hospitalizations nationwide, coinciding with a spate of flu and RSV infections around the same time.

The JN.1 variant is estimated to account for about 22% of recent COVID cases across the country, according to CDC data from late April.

Another FLiRT variant, KP.1.1, comprises over 7% of COVID cases nationwide, the CDC data shows.

Nationwide, about 23% of adults and 14% of children were reported to be up to date on COVID vaccines as of late April, according to the CDC, based on data from the National Immunization Survey.

“For people who have fragile immune systems, they should take precautions around large crowds and places where they can be exposed,” said Dr. Elizabeth McNally, the director of the Northwestern University Feinberg School of Medicine Center for Genetic Medicine. “For older people, it’s generally a good idea to stay up to date on vaccinations since immunity does wane with age.”

While vaccination rates have tapered off, McNally noted that this “is on the backdrop of a great deal more immunity from repeated exposures from natural infection and vaccination,” compared with the early stages of the COVID pandemic.

“This translates to quicker recoveries and less prolonged illness when people do get COVID,” she said. “In 2020, we were dealing with a virus for which humanity had little immunity. That is, thankfully, very different now.”