Four Things You Should Know about COVID FLiRT

Author

Dr. Todd Ellerin

Todd Ellerin, MD, Director of Infectious Disease

A graphic showing the spike protein of the COVID FLiRT variant
The COVID FLiRT variants are driving this summer's wave of infections.

After five summers with us, COVID-19 has settled in.

And it’s become a bit of a FLiRT.

FLiRT is the name given to the latest variants, which now account for more than 75% of the new COVID cases in the U.S. 

Called FLiRT due to the technical names for its spike protein mutations, which include the letters F, L, R and T, FLiRT is a subvariant of last winter’s dominant strain Omicron, and is driving this summer’s COVID wave.  

Centers for Disease Control and Prevention (CDC) data for mid-July shows that COVID test positivity rates have reached 12.6% nationally and 10.9% in Massachusetts.  

COVID-related emergency room visits have been increasing across the U.S. and wastewater viral activity has reached high or very high levels in 35 states – another indicator that infections are on the rise.

To learn the latest about COVID FLiRT and what we can expect heading into fall, we caught up with South Shore Health’s Director of Infectious Disease, Todd Ellerin, MD.  

Here are four things to know about COVID FLiRT.

COVID FLiRT is more contagious but does not cause more severe illness

As we have seen before with COVID, each progeny or offspring variant is more contagious, but the good news is that they also tend to be less severe.  That’s because after years of living with COVID, through vaccinations and infections we have greater population immunity. 

That being said, the COVID FLiRT variants KP.1, KP.2, KP.3 and a newer strain called LB.1 – all of them spinoffs of Omicron’s JN.1 – have spike protein mutations that make them better at evading prior immunity. 

The fact that most Americans are not up to date with their COVID vaccinations and already have waning immunity is also contributing to this summer’s uptick in cases.  

Only about 14% of eligible children and 22% of adults (1 in 5) received the 2023/24 COVID-19 vaccine last fall. In comparison, 42% got a flu shot last season.

The CDC strongly recommends that everyone over 6 months of age get the updated COVID-19 vaccine when it is available. 

COVID FLiRT Symptoms, treatment, and recovery  

Symptoms and the duration of illness from COVID FLiRT infection are similar to earlier strains of the virus. Common symptoms include fatigue, fever, body aches, chills, congestion, cough, runny nose, sore throat, headache, loss of taste and/or smell. Some people may also experience gastrointestinal symptoms.

Fortunately, Paxlovid and other antiviral medications recommended for high-risk individuals, are just as effective in treating these new variants.

A test vial for the COVID FLiRT variant strain KP.2
FDA vaccine regulators have instructed manufacturers of the updated shot to target COVID FLiRT's KP.2 strain which is now dominant.

People who become ill with any respiratory virus should follow the updated CDC guidance, by staying home and away from others until their symptoms have improved and they have been fever free without the use of fever-reducing medication for at least 24 hours. 

After returning to normal activities, the CDC recommends following infection prevention steps like frequent handwashing and wearing a mask. 

Constantly changing COVID challenges vaccine regulators

One of the surprising and challenging things about COVID is its continual and rapid evolution; it just keeps throwing new mutations, like COVID FLiRT at us.  

The virus mutates so quickly, it’s difficult for even the vaccine regulators to figure out which variant strains to include in this year’s COVID shot.

In early June, the Federal Drug Administration’s (FDA) Vaccine and Related Biological Products Advisory Committee unanimously voted to update the COVID-19 vaccine composition to target the JN.1 subvariant. 

Within weeks, after seeing the increasing dominance of the COVID FLiRT variants, the FDA instructed vaccine manufacturers to use the KP.2 strain to match the virus strains now widely circulating.

Despite the change, Moderna, Novavax, and Pfizer still expect to have the 2024/25 COVID-19 vaccine available by September.

Vaccine is still our best defense against severe COVID illness

A photo of several vials of COVID-19 vaccine
COVID-19 vaccines continue to be the best defense against the virus. The updated 2024/25 shot is expected to be available by September.

COVID-19 isn’t going away. We’ve seen it continue to mutate and persist.

And it has become bi-seasonal – we’re seeing summer and winter peaks each year.

But as we head into our 5th fall season living with the virus, we are well equipped to reduce the risk of infection and prevent severe illness by getting the updated COVID-19 vaccine.

Because immunity wanes and COVID keeps finding ways to change, infect and spread, staying up to date on the vaccine is important.

For most people, as with the flu shot, one COVID-19 vaccine annually in the fall is enough. Higher risk groups, including people who are over age 65 or immunocompromised, should get two shots per year – one in the fall and another in the spring.

We’ve come so far and made tremendous progress since COVID arrived four years and four months ago. 

During these interpandemic times, we need to dig in and keep the scientific “full court press” on COVID and other viruses, by developing even better vaccines, antivirals and game plans, so when the next pandemic hits, we’re prepared.

 

Todd B. Ellerin, MD is Director of Infectious Disease at South Shore Health.