The CDC has confirmed that KP.3, a new variant of the SARS-CoV-2 coronavirus descendant of JN.1, is now dominant in the United States. It is a virus from the “FLiRT” family. What it means and what are the symptoms of COVID-19 caused by these pathogens.
In the United States there is a new dominant variant of the coronavirus SARS-CoV-2: KP.3. Dr. Rosa Norman of the CDC confirmed this in an interview with USA Today: “Currently, KP.3 viruses are estimated to make up between 16 and 37 percent of all SARS-CoV-2 viruses in the United States,” explained the scientist. To understand the leap forward made, it is enough to know that it went from an estimate of 9.4 percent to May 11th at one of the 25 percent on June 8th. If the name KP.3 sounds familiar to you, it is not surprising: until today, in fact, the dominant variant scepter in the USA was held by KP.2, which was also detected in Italy for the first time at the beginning of May. In turn he had ousted JN.1, of which KP.2 and KP.3 are direct descendants.
Based on current data, it is likely that in the coming weeks KP.3 will be able to take root and grow further both in the USA and elsewhere, being able to count on a (presumed) better ability to transmission and therefore of evading immune defenses such as KP.2, both those “trained” by anti-Covid vaccines – which however remain extremely effective in preventing the form serious of the disease – and natural ones linked to previous infections. For updated vaccines against the descendants of JN.1 we will have to wait until the autumn, as Professor Adrian Esterman, epidemiologist and professor of Biostatistics at the University of South Australia, told Newsweek. But there is no information yet on the effectiveness against this specific variant.
Variant under monitoring from May 2024
KP.3 was first isolated in biological samples on 11 February this year, but only at the beginning of May was it classified as variant under monitoring (VUM) by the World Health Organization (WHO) and included in the “Tracking SARS-CoV-2 variants” surveillance system. As indicated, it is a direct descendant of JN.1, from which it diverges in three specifications mutations on the S protein or Spike, the “biological pick” that the SARS-CoV-2 coronavirus uses to attach itself to the receptor of human cells, infect them and trigger the disease called COVID-19. The mutations are S:F456L, S:Q493E and S:V1104L. Of these KP.2 presents only the last one. Definitive data on the infectious capabilities of the new variant are not yet available, but having become dominant it is easy to think that they are superior to those of the variant that preceded it.
Covid-19 changes again: what we know about the new KP.2 variant that arrived in Italy
What are FLiRT variants
Interestingly, JN.1 and the two descendant variants are part of a group that scientists call “FLiRT”. The name is linked to the peculiar way in which mutations occur in amino acids on the S or Spike protein; those classified as F interchange with L, while those classified as R with T. All of these viruses derive from the original variant of concern Omicron, discovered in South Africa at the end of 2021 and has since spread throughout the world through multiple daughter lineages, including recombinant ones. The positive aspect is that compared to those that preceded it, it has proven to be a lot less deadlyalso thanks to the protection offered by vaccines and widespread immunization.
What are the symptoms of KP.3
As regards i symptoms, the CDC points out that they can vary from person to person and based on the type of variant involved, although there is a generic list you can refer to. Those indicated include fever; chills; cough; breathing difficulties; muscle pain (myalgia); cephalea (headache); loss or alteration of taste and/or smell; runny nose (rhinorrhea); and gastrointestinal problems such as nausea, vomiting, and diarrhea. Despite KP.3’s ride, experts do not currently expect it to have a significant impact on the number of infections and the severity of the disease. Professor William Schaffner of Vanderbilt University told USA Today that it is unlikely to expect “peculiar symptoms” from the new FLiRT variants.
