What are the FLiRT COVID variants and how do they differ from previous strains?

So-called FLiRT variants of the SARS-CoV-2 coronavirus that causes COVID-19 were the predominant forms of the virus circulating globally this year, according to the World Health Organization

The FLiRT alias is an acronym for the mutation sites shared by the variants in the viral spike protein. One of them, called KP.2, has become the most commonly circulated variant in the United States in the past month, according to the US Centers for Disease Control and Prevention.

Here’s what you need to know about FLiRT.

How do FLiRT variants differ from previous variants?

The FLiRT variants, which also include the “parental” JN.1 lineage of KP.2, have three key mutations in the spike protein that could help them evade antibodies, according to Johns Hopkins University.

Are FLiRT variants more transmissible or are they likely to cause more severe disease?

Dr. Aaron Glatt, chief of infectious diseases at Mount Sinai South Nassau Hospital in Oceanside, New York, and a spokesman for the Infectious Diseases Society of America, said he has seen no evidence of an increase in illness or hospitalizations, based on the data he has collected and experience with the his own patients.

“There have been some significant changes in the variants, but I think lately it hasn’t been as significant, probably because of the immunity that many, many people already have” from previous illness and vaccination.

CDC data suggests that COVID-related hospitalizations have trended downward in recent weeks, and the number of emergency department patients testing positive for COVID has been nearly flat over the past month.

The data suggests that the rates of COVID are also decreasing year over year. The rate of hospitalizations for COVID-19 is less than half what it was a year ago, and the amount of the antiviral Paxlovid currently being prescribed for COVID-19 is down about 60% from last year, according to analyst notes .

Do current vaccines against flirting variants work?

Current vaccines should still have some benefit over the new variants, Glatt said.

Starting in 2022, health regulators asked vaccine makers to design new versions of the COVID-19 vaccines to better target circulating variants. Last month, Europe’s regulator said vaccine makers should target the JN.1 variant. US experts and regulators will meet to discuss vaccine design on June 5, after postponing the meeting from May 16 in order to have more time to “obtain surveillance data and other information.”

The makers of vaccines based on messenger RNA (mRNA) technology – Pfizer, with partner BioNTech and Moderna – say they are waiting for the June 5 meeting before finalizing the design of their next vaccines.

Novavax, which produces a more traditional protein-based vaccine that takes longer to make, has begun producing a vaccine targeting JN.1 in line with recommendations from European regulators.