While the season of respiratory viruses could end soon with the arrival of summer, a new family of viruses is circulating in the United States variations of Covid-19, call FliRT, which is raising concern among experts about a potential new wave of infections this summer. In particular, the variant is under the spotlight KP.2, which in recent weeks has rapidly overtaken JN.1, the omicron subvariant that caused the surge in cases last winter, to now become the dominant strain in the US. According to the latest estimates from the Centers for Disease Control and Prevention (CDC), in fact, KP.2 is spreading quickly, currently accounting for one in four infections nationwide. But what are the FLiRT variants, what symptoms do they cause and what is the effectiveness of the vaccines available today?
What are the FLiRT variants?
The so-called FliRT variants are distant descendants of the omicron variants, but being quite recent, experts are still studying its characteristics. In the case of KP.2 we know that it comes from the variant JN.1., but differs from this for some mutations that seem to give it a greater advantage in terms of contagiousness compared to the previous ones. “It’s still early days, but the initial impression is that this variant (KP.2) is quite transmissible”, comments a Today William Schaffner, professor of infectious diseases at Vanderbilt University Medical Center.
Symptoms of the KP.2 variant
The good news is that today there is no evidence to support that the new variant can cause more severe disease than the previous ones. As they remember According to CDC, the type and severity of symptoms depend on a person’s underlying health and immune system, rather than the variant that caused the infection. In general, therefore, we remember that the symptoms of the FLiRT variants are similar to those caused by JN.1, namely: sore throat, cough, tiredness, fever, muscle pain, loss of taste or smell, difficulty breathing, nausea, vomiting and diarrhea. As Pier Luigi Lopalco explained to Republic, “even in the very probable case that KP.2 arrives in Italy and it spreads, as it is doing in the United States, the symptoms should not be more severe than those typical of a seasonal flu.”
Vaccines still work
Some early investigations suggest that KP.2 has mutated to such an extent that current vaccines and immunity from previous infections may provide partial protection. The person responsible, according to a study that appeared in bioRxivit would be a change in the structure of the spike protein which would provide greater resistance. “Early laboratory studies indicate that vaccines will continue to provide protection against KP.2: slightly less protection, but not zero by any means,” adds Schaffner. In fact, as the virus mutates, it is becoming progressively different from the Omicron targeted in the latest updated recall released in the fall of 2023. “We expect that to happen and anticipate that the plan will be to have an updated vaccine available in the fall for everyone”, continues the expert. It is important to remember, however, that vaccines, even if they do not prevent infection, offer protection by limiting the risk of severe disease, hospital admissions and complications related to Covid-19.
Will there be a summer wave?
Although with the arrival of summer people will spend less time indoors, thus reducing opportunities for KP.2 to be able to spread, it is still too early to understand whether it will still be able to cause asummer wave, not only in the United States, but also globally. In the past, experts point out, the new coronavirus caused summer waves, although often smaller than the winter ones. There seasonality Covid-19, however, is something scientists are still trying to understand, but one thing is for sure: “This virus is now integrating into our population and our lifestyle,” concludes Schaffner.
