XBB.1.16 ‘Arcturus’ Is New Covid-19 Variant Under Monitoring By The WHO

Guess what? There’s yet another Covid-19 coronavirus variant spreading around the world and in the U.S. This one has the oh-so-easy-to-remember name XBB.1.16 because when has the name of another Omicron subvariant started with the letters XBB, right? On March 22, the World Health Organization (WHO) classified the XBB.1.16 as a new variant under monitoring (VUM), which isn’t as serious as a variant of interest (VOI) which isn’t as serious as a variant of concern (VOC). But the spread of the XBB.1.16 seems to have fueled what’s been called by the India-based media publication Business Today a “massive surge” of Covid-19 cases in India and sparked the return of face mask mandates there. These days the term “massive surge” isn’t great to hear unless you are talking about chocolate or sex. So the big question is how concerned should you be about this new subvariant that some have unofficially dubbed the “Arcturus” subvariant?

Well, “Acturus-lly,” the XBB.1.16 has gone from being about 0.21 percent of all Covid-19 cases worldwide in late February to an estimated 3.96% a month later. In the U.S,, the XBB.1.16 accounted for an estimated 7.2% of all Covid-19 samples from April 9 to April 15, according to the Centers for Disease Control and Prevention (CDC). That’s up from 3.9% the week before and 2.1% the week prior to that.

So it does look like the XBB.1.16 has a “growth advantage” over other existing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants. A growth advantage may sound like a good thing when you are using the term to describe yourself or parts of you. But it a more ominous term when being used to describe a pathogen like the SARS-CoV-2. In this case, it’s when a given variant or subvariant has characteristics that makes it better able to spread than others.

During a March 29 press conference, Maria Van Kerkhove, PhD, the WHO’s Technical Lead on Covid-19, did indicated that the XBB.1.16 is “actually very similar in profile to XBB.1.5. It has one additional mutational mutation in the spike protein which in lab studies shows increase infectivity, as well as potential increased pathogenicity.” Increased infectivity means that the XBB.1.16 may be more likely to infect you than other variants and subvariants. Potential increased pathogenicity suggests that the XBB.1.16 could potentially, maybe, perhaps, possibly cause more severe Covid-19 than other existing variants and subvariants. But the jury is still out on this latter issue. Van Kerkhove added, “This is one to watch. It has been in circulation for a few months.”

This is why the WHO has categorized the XBB.1.16 as a VUM three months after it was first detected on January 23. The WHO’s formal working definition of a VUM is one “with genetic changes that are suspected to affect virus characteristics and early signals of growth advantage relative to other circulating variants (e.g. growth advantage which can occur globally or in only one WHO region), but for which evidence of phenotypic or epidemiological impact remains unclear, requiring enhanced monitoring and reassessment pending new evidence.” It would become a VOI if it’s already demonstrated a clear “growth advantage over other circulating variants in more than one WHO region with increasing relative prevalence alongside increasing number of cases over time, or other apparent epidemiological impacts to suggest an emerging risk to global public health.” It would become a VOC if it either showed that it causes more severe disease, significantly affects the ability of health systems to provide care to patients, or is able to evade protection against severe Covid-19 from vaccination.

The XBB.1.16 has already appeared in at least 29 countries, according to the WHO. As mentioned earlier, it’s been making its mark on India. The April 14 Business Today article indicated that India had reported “11,109 cases in the last 24 hours, as per the health ministry data on Friday.” It also mentioned that India has 49,622 active Covid-19 cases and a fatality rate of 1.19%. This was the fifth consecutive day that India had reported a rise in Covid-19 cases. Mike Honey, who is the Technical Lead for Manga Solutions based in Melbourne, Australia, provided on Twitter this animated map showing the spread of the “Acturus” variant around the world:

Now, the name “Arcturus” ain’t official, just like “Kraken” and “Orthus” names of earlier emerging subvariants weren’t official either. The continued use of letter and number combos that sound more like Star Wars droids has made it more difficult to know what Omicron subvariants people are referring to, which has probably prompted the emergence and use of these unofficial nicknames. “Arcturus” is a Latinized version of the ancient Greek name Arktouros, which means “Guardian of the Bear,” because who wouldn’t want a bear to be guarded, right?

Speaking of bear, has this new subvariant brought to bear another Covid-19 surge in the U.S. yet? Well, it may be that one can “bearly” tell these days because so many folks seem to have abandoned getting officially tested for Covid-19. When people are home testing or not getting tested at all, the reported Covid-19 cases probably don’t really reflect what’s really going on with the pandemic. The CDC numbers still show a downward trend in cases since mid-January with 101,437 reported Covid-19 cases for the week ending April 12. But as they say, who the bleep knows. Plus, reported cases always lag what’s happening right now since it takes time for people to get tested and public health officials to learn of these cases.

All of this is a reminder that although many political leaders seem to want to shove Covid-19 under the metaphorical rug and act as if its not a problem anymore, the virus certainly hasn’t agreed to simply go away. It is still important to keep track of what variants and subvariants continue to emerge and what problems they may bring.

There have been anecdotes of more people reporting conjunctivitis symptoms with XBB.1.16 infections. Conjunctivitis, which is popularly (or maybe unpopularly) known as pink eye, is when your conjunctiva gets inflamed and swollen. The conjunctiva is the thin layer of tissue that covers the white part of your eye and the inside of your eyelids. Tatiana Prowell, MD, an Associate Professor of Oncology at Johns Hopkins School of Medicine, warned on Twitter that the red, itchy, or sticky eye symptoms associated with such a viral conjunctivitis could be mistaken for allergies:

Keep in mind, though, that anecdotes are not the same as official data and well constructed medical studies. So, it’s not clear yet how common conjunctivitis may be for those who get infected with the XBB.1.16 and what other symptoms and problems may emerge. In other words, it’s not clear yet what “Arcturus” may actually bring to bear, so to speak. What’s clear, though, is that this new subvariant does indeed bear close watching.