Surprise, surprise, there’s yet another new COVID-19 variant on the loose and spreading. It is called XFG and has already been reported in 38 countries including the U.S. And if you are wondering who believes that this variant should be closely watched, it’s the World Health Organization, that’s WHO. The WHO has recently added XFG to its “variant under monitoring” or VUM list.
Will XFG End Up Overtaking NB.1.81?
lg:min-h-[4.75rem] dropcap text-left”>It’s been less than two months since I covered in Forbes a new VUM, the NB.1.8.1, which became a VUM in May due to its rapid spread. The NB.1.8.1 has since become the dominant variant in many countries around the world. For example, according to the U.S. Centers for Disease Control and Prevention so-called “nowcasting,” from June 8 to June 21, NB.1.8.1 comprised 42% of the COVID-19 samples in the U.S. that had undergone genetic testing, making it the most common among all variants. Meanwhile, this percentage was 14% for XFG, placing it as already the third most common variant during that time period.
But—and it’s a big but—take such CDC data with a fanny pack of salt. It’s difficult to tell what’s currently really happening with COVID-19 and the severe acute respiratory syndrome coronavirus 2 variants in the U.S. Despite having, oh, five years to do so, the U.S. never really developed a comprehensive and reliable COVID-19 surveillance system. The CDC’s case estimates have long relied on those infected first getting formally tested at clinics and hospital and then those test results ultimately being reported to public health officials and the CDC. However, these days, who knows how many people infected with the SARS-CoV-2 in the U.S. will even end up getting tested.
The month of May saw fairly rapid spread of the XFG in many parts of the world. From the week of May 5 to the week of May 26, XFG went from being in 10.6% of sequenced COVID-19 samples to 16.7% of them in Europe, 7.8% to 26.5% of them in the Americas region, and 17.3% to 68.7% of them in the Southeast Asia Region. In Southeast Asia, the XFG variant has been behind a recent surge in COVID-19 cases and hospitalizations.
What The WHO Designation Of XFG As A ‘Variant Under Monitoring’ Means
These rises have led to XFG’s inclusion on its “variant under monitoring” or VUM list on June 25. As I have described in Forbes previously, a WHO VUM isn’t yet as concerning as a WHO variant of interest which isn’t yet as concerning as a WHO variant of concern. A VUM is essentially something that public health authorities should pay close attention to and monitor closely. The WHO indicates that “the main objective of this category is to investigate if this variant (and others closely related to it) may pose an additional threat to global public health as compared to other circulating variants.” In other words, stay tuned for more information.
A VUM could always become a variant of interest or VOI, which is where a SARS-CoV-2 variant has documented changes “that are known to affect how the virus behaves or its potential impact on human health.” Such changes can affect the virus’s ability to spread, cause serious disease, detectability or treatability. A VOI could, in turn, become a variant of concern or VOC. This is where the SARS-CoV-2 variant can do at least one of the following things in the words of the WHO:
- “It can cause a detrimental change in disease severity”
- “It can have a substantial impact on the ability of health systems to provide care to patients with COVID-19 or other illnesses and therefore require major public health interventions””
- “There is a significant decrease in the effectiveness of available vaccines in protecting against severe disease.”
XFG Is A Combination Of LF.7 and LP.8.1.2.
XFG’s becoming a VUM means that this variant has graduated to the big leagues, which isn’t easy. Since the SARS-CoV-2 mutates seemingly as often as celebrities change outfits, a lot of new variants will keep emerging over time. Combine these new variants with the new variants that emerge from existing variants combining with each other. These variants compete with each other to keep infecting humans and spread further and further. Most of the new variants don’t go very far or don’t make much noise because they don’t have any fitness or competitive advantages over the currently dominant variants. But every few months or so, a new variant emerges that seems to have the stuff to outcompete all other variants.
Enter the XFG variant, which is part of the oh-so-familiar Omicron family. XFG is actually a combination of the LF.7 and LP.8.1.2 variants, which were combinations of previous variants themselves. Therefore, the XFG is a combination of combinations. The XFG has nine more mutations in its spike proteins than the NB.1.8.1 variant. Although it’s not clear yet how these mutations may affect the functioning of the virus, the spike protein is what the virus uses to connect with and get into human cells.
Vaccines seem to work against it
Scientists are currently studying how well people are protected against severe disease from XFG. Researchers conducted lab studies using human cells and a “pseudovirus” stand-in for XFG, as well as animal studies, and found slightly lower immune responses to XFG.
While the data aren’t complete yet, those results are encouraging since they suggest that existing vaccines used in the U.S., which target JN.1, should continue to provide some protection against severe disease and hospitalization—even if it’s less robust than protection against the JN.1 variant specifically. WHO says the genetic analysis of XFG also shows that antiviral drugs nirmatrelvir (Paxlovid) and remdesivir (Veklury) should also be effective.
It derives from the JN.1 Omicron group, which is the target of the latest COVID-19 vaccine.
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