COVID-19 variant trackers are now closely monitoring the emergence of a new virus variant called XEC, which has now been found around the world and in half of the U.S. states.
Unlike previous, more highly mutated strains that have worried experts, health officials have so far not expressed concern about this variant.
XEC's emergence comes as trends in coronavirus infections remain at “high levels” but have now slowed significantly following a summer wave of infections that peaked last month. Modelers at the Centers for Disease Control and Prevention estimate that virus cases will likely rise again during the winter and peak in mid-January.
Here's the latest information we know about the new XEC variant:
Which states are reporting XEC cases?
At least 25 states have already reported at least one case with the strain's characteristic mutations, according to preliminary data from more than 100 cases in the United States from the global virus database GISAID.
New Jersey labs have reported the most XEC infections (at least 15) of any state. Only California and Virginia have reported at least 10 cases so far. New Jersey's detections primarily come from samples collected through the CDC's testing program for arriving travelers who clear customs at Newark Liberty International Airport.
Some of the earliest cases in the United States were reported by scientists at Virginia Tech's Fralin Biomedical Research Institute lab, where samples were taken from patients in July.
“We are not seeing any specific trends,” Carla Finkielstein, head of the institute's molecular diagnostics laboratory, said in an email. “We are not seeing any specific trends. We need to continue to monitor the arrival of samples and continue broader genomic screening.” said.
Finkielstein said most of the samples came from hospitals in southwest Virginia, but it's unclear why exactly they were tested.
“Unfortunately, we don't have demographic data on these patients, so we don't know if they were hospitalized or if the samples were collected during, for example, an emergency room visit,” Finkielstein said. .
Dr. Celine Gounder, medical contributor for CBS News and general public health editor for KFF Health News, says the emergence of new variants is not surprising.
“Viruses mutate as they pass from person to person. This is normal and new variants will emerge,” she explained. “XEC is just the latest, but there will be more to come.”
Why is the XEC variant in the news?
Variant trackers first proposed labeling the new strain as XEC in early August, after labs in Europe and Virginia reported infections around the same time.
The rise of the variant has attracted recent attention online, with the growth of XEC across Germany in recent weeks drawing the attention of variant trackers like Australian X consultant Mike Honey. There is.
But others in the variant-tracking community are worried that this strain could lead to other strains on the rise, especially since a closely related strain called KP.3.1.1 has already reached dominance in many countries. Skeptical of defeat.
According to CDC estimates released last Friday, KP.3.1.1 now accounts for more than half of the cases in the United States and has been dominant for several weeks.
If XEC grows in dominance, it could represent the latest in several months of variants that have led to relatively small changes in the threat posed by circulating variants.
This is in contrast to the discovery of the highly mutated BA.2.86 variant that worried health officials this time last year. That's because the mutant strain had accumulated a worrying number of genetic changes compared to the initial strain.
A descendant of last year's BA.2.86 strain eventually became known as JN.1 and went on to dominate last winter's wave of infections.
The “X” in the name of XEC comes from the fact that this strain appears to be a “recombinant” of two other closely related parent variants called KS.1.1 and KP.3.3 . KS.1.1 and KP.3.3 are both descendants of the JN.1 strain.
Does XEC result in different symptoms and vaccine effectiveness?
“CDC is not aware of any specific symptoms associated with XEC or other co-circulating SARS-CoV-2 strains,” an agency spokesperson said in a statement.
A CDC spokesperson said Americans are still recommended to get the latest coronavirus vaccine this fall and winter. Those shots were given the green light last month with an update targeting the KP.2 strain of the virus.
“At this time, we expect that treatments and vaccines for COVID-19 will continue to be effective against all circulating variants,” a CDC spokesperson said. “We will continue to monitor the effectiveness of treatments and vaccines against the emerging variants.”
Gouder said public health officials are trying to make vaccines “as close as possible to the variants that are currently circulating. Viruses move faster than we do, so it's never going to be perfect, but the vaccines are going to match pretty well.” We are doing so,” he explained. . ”
The Food and Drug Administration has in recent weeks defended its selection of KP.2 for this year's revised vaccine, ignoring recommendations from a panel of outside advisers to the World Health Organization and the Food and Drug Administration and recommending instead. The parent vaccine, JN.1, was targeted.
Asked about XEC, an FDA spokesperson said Thursday that the latest vaccine “offers better protection against the variants currently in circulation, particularly against the most severe outcomes, including hospitalization and death.”
“We will continue to monitor the safety and effectiveness of the vaccine against emerging variants,” FDA spokeswoman Shelley Duvall Jones said in a statement.
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