For the past several months, Omicron subvariants BA.4 and BA.5 have dominated COVID-19 cases in the U.S. But now, there’s a class of new COVID subvariants on the rise and one in particular is getting plenty of attention. It’s called XBB—or Gryphon—and there’s a chance it could overtake everything else out there.
XBB is getting a lot of buzz because it spreads fast—and seems to be able to evade immunity that people have built up from having a previous COVID-19 infection or getting the vaccine, says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine. Still, Dr. Schaffner says, “it’s early days and we have a lot to learn.”
Here’s what we know about XBB so far, and why doctors are keeping a close eye on it.
What is the XBB COVID variant?
XBB is one of the “new class” of Omicron variants that are spreading fast right now, says Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York. That includes BQ.1.1, BQ.1, BQ.1.3, BA.2.3.20, and XBB, he says.
“XBB is a hybrid version of two strains of the BA.2 form of Omicron,” explains Amesh A. Adalja, M.D., a senior scholar at the Johns Hopkins Center for Health Security. It’s currently “spreading efficiently in Singapore,” he adds.
The variant was first detected in August 2022 in India, and has been detected in more than 17 countries since then, including Australia, Bangladesh, Denmark, India, Japan and the U.S., per Singapore’s Ministry of Health.
XBB is thought to have the best ability to evade antibody protections of these newly emerged COVID variants, according to a pre-print study from researchers in China. That study said that the new strains of Omicron, and XBB in particular, “are the most antibody-evasive strain tested, far exceeding BA.5 and approaching SARS-CoV-1 level.” (SARS-CoV-1, in case you’re not familiar with it, is the strain of coronavirus that causes SARS, a respiratory virus that can cause severe illness.)
Meaning, the vaccine and having previously had COVID-19 are not thought to offer the same level of protection against XBB as they have with previous strains of COVID-19. Antibody drugs like Evusheld and bebtelovimab may also not be very effective against XBB, the pre-print study says.
“These variants are evolving to evade protection,” Dr. Russo says. The bivalent booster is “likely going to be protective against severe disease” with XBB, but will be “imperfect against preventing infection,” Dr. Russo says.
Don’t panic, though. “When it comes to evasion of vaccine protection, it’s important to recognize that vaccine protection is not all or none,” Dr. Adalja says. “Even with immune-evasive variants, vaccine protection against what matters most—severe disease—remains intact.”
XBB variant symptoms
So far, symptoms of XBB seem to be similar to what they’ve been with COVID-19 in general. According to the Centers for Disease Control and Prevention (CDC), those can include:
· Fever or chills
· Cough
· Shortness of breath or difficulty breathing
· Fatigue
· Muscle or body aches
· Headache
· New loss of taste or smell
· Sore throat
· Congestion or runny nose
· Nausea or vomiting
· Diarrhea
How contagious is the XBB subvariant?
Like other strains of Omicron, XBB is thought to be very contagious. Singapore’s Ministry of Health notes that the variant now makes up 54% of COVID-19 cases in the country, up from 22% the week before.
Singapore’s Ministry of health says that XBB is “at least as transmissible as currently circulating variants” but adds that “there is no evidence that XBB causes more severe illness.”
When will the XBB subvariant peak?
There are a lot of unknowns about XBB right now. While it’s been detected in the U.S., BA.5 and BA.4.6 continue to be the dominant variants in this country, per CDC data.
Other variants are also started to spread at the same time, Dr. Adalja says, and it’s unclear which will displace BA.4.6 and BA.5 in the U.S., if they will at all. “It’s likely to spread to some degree in the U.S. but unclear if it—or some other related variant such as BQ.1.1—will become dominant,” he says.
Dr. Schaffner says there is “some concern” about XBB and fellow variants on the rise. “Watching what happens over the next several weeks is important,” he says.
News
Scientists study lipids cell by cell, making new cancer research possible
Imagine being able to look inside a single cancer cell and see how it communicates with its neighbors. Scientists are celebrating a new technique that lets them study the fatty contents of cancer cells, [...]
Antibiotic Breakthrough: Revolutionary Chinese Study Paves Way for Superbug Defeating Drugs
New research reveals that fluorous lipopetides act as highly effective antibiotics. Bacterial infections resistant to multiple drugs, which no existing antibiotics can treat, represent a significant worldwide challenge. A research group from China has [...]
Signs of Multiple Sclerosis Show Up in Blood Years Before Symptoms Appear
UCSF scientists clear a potential path toward earlier treatment for a disease that affects nearly 1,000,000 people in the United States. By Levi Gadye In a discovery that could hasten treatment for patients with multiple [...]
Advanced RNA Sequencing Reveals the Drivers of New COVID Variants
A study reveals that a new sequencing technique, tARC-seq, can accurately track mutations in SARS-CoV-2, providing insights into the rapid evolution and variant development of the virus. The SARS-CoV-2 virus that causes COVID has the unsettling [...]
No More Endless Boosters? Scientists Develop One-for-All Virus Vaccine
End of the line for endless boosters? Researchers at UC Riverside have developed a new vaccine approach using RNA that is effective against any strain of a virus and can be used safely even by babies or the immunocompromised. Every [...]
How Are Hydrogels Shaping the Future of Biomedicine?
Hydrogels have gained widespread recognition and utilization in biomedical engineering, with their applications dating back to the 1960s when they were first used in contact lens production. Hydrogels are distinguished from other biomaterials in [...]
Nanovials method for immune cell screening uncovers receptors that target prostate cancer
A recent UCLA study demonstrates a new process for screening T cells, part of the body's natural defenses, for characteristics vital to the success of cell-based treatments. The method filters T cells based on [...]
New Research Reveals That Your Sense of Smell May Be Smarter Than You Think
A new study published in the Journal of Neuroscience indicates that the sense of smell is significantly influenced by cues from other senses, whereas the senses of sight and hearing are much less affected. A popular [...]
Deadly bacteria show thirst for human blood: the phenomenon of bacterial vampirism
Some of the world's deadliest bacteria seek out and feed on human blood, a newly-discovered phenomenon researchers are calling "bacterial vampirism." A team led by Washington State University researchers has found the bacteria are [...]
Organ Architects: The Remarkable Cells Shaping Our Development
Finding your way through the winding streets of certain cities can be a real challenge without a map. To orient ourselves, we rely on a variety of information, including digital maps on our phones, [...]
Novel hydrogel removes microplastics from water
Microplastics pose a great threat to human health. These tiny plastic debris can enter our bodies through the water we drink and increase the risk of illnesses. They are also an environmental hazard; found [...]
Researchers Discover New Origin of Deep Brain Waves
Understanding hippocampal activity could improve sleep and cognition therapies. Researchers from the University of California, Irvine’s biomedical engineering department have discovered a new origin for two essential brain waves—slow waves and sleep spindles—that are critical for [...]
The Lifelong Cost of Surviving COVID: Scientists Uncover Long-Term Effects
Many of the individuals released to long-term acute care facilities suffered from conditions that lasted for over a year. Researchers at UC San Francisco studied COVID-19 patients in the United States who survived some of the longest and [...]
Previously Unknown Rogue Immune Key to Chronic Viral Infections Discovered
Scientists discovered a previously unidentified rogue immune cell linked to poor antibody responses in chronic viral infections. Australian researchers have discovered a previously unknown rogue immune cell that can cause poor antibody responses in [...]
Nature’s Betrayal: Unmasking Lead Lurking in Herbal Medicine
A case of lead poisoning due to Ayurvedic medicine use demonstrates the importance of patient history in diagnosis and the need for public health collaboration to prevent similar risks. An article in CMAJ (Canadian Medical Association [...]
Frozen in Time: How a DNA Anomaly Misled Scientists for Centuries
An enormous meteor spelled doom for most dinosaurs 65 million years ago. But not all. In the aftermath of the extinction event, birds — technically dinosaurs themselves — flourished. Scientists have spent centuries trying [...]