There is a new coronavirus variant in town. KP.2, a member of the so-called FliRT variants, nicknamed after their mutations, has become the dominant coronavirus strain in the United States, according to the US Centers for Disease Control and Prevention. These FliRT variants have certain mutations in common but are still part of the Omicron family of the coronavirus.

For the period from April 28 to May 11, nearly 30% of new cases were caused by KP.2, up from less than 16% in the two-week period before that.

What should people know about this new variant? What are the symptoms of infection? Do vaccines still work against the new strain? Is a home test still reliable? How long should people isolate if they contract KP.2? Who should take antiviral treatments if they contract this type of Covid-19? And what is the guidance for immunocompromised individuals — should they start masking again?

To guide us through these questions, I spoke with CNN wellness expert Dr. Leana Wen. Wen is an emergency physician and clinical associate professor at the George Washington University. She previously served as Baltimore’s health commissioner.

Home tests will likely still detect KP.2, the new coronavirus variant. Grace Cary/Moment RF/Getty Images

CNN: What should people know about this new variant, KP.2?

Dr. Leana Wen: Since the start of Covid-19, we have been discussing new variants. The original strain of the virus was displaced by the Alpha variant. Then we had Beta, then Delta and then Omicron.

KP.2 is part of the Omicron family. It appears to be displacing JN.1 and similar subvariants, which previously were the dominant variants in the United States.

Whenever there is a new variant, there are three key questions to ask: Is it more contagious? Does it cause more severe disease? And do existing vaccines and treatments work on it?

One reason a new strain displaces the previously dominant ones is that it is as contagious or more so. That means KP.2 could spread very easily, which is something we have seen throughout Covid-19: that the coronavirus is extremely contagious and thus difficult to avoid.

The good news is that KP.2 does not appear to cause more severe disease. Indeed, hospitalizations associated with Covid-19 are at record lows. And there is no reason to believe that existing vaccines and treatments would stop working against it.

CNN: What are the symptoms of infection with KP.2?

Wen: Most people who contract the coronavirus will never know what variant is causing their symptoms. Symptoms of Covid-19 infection include runny nose, sore throat, headache, fevers, cough and body aches. Some people may experience more severe symptoms such as shortness of breath. Covid-19 could also exacerbate underlying conditions such as heart failure.

None of these symptoms are specific to KP.2, which so far has not been reported to be associated with unique symptoms that distinguish it from other coronavirus infections. It’s important to remember that in many individuals, Covid-19 symptoms may be difficult to differentiate from other viral infections, such as the flu or common cold.