XBB, BQ.1.1, BA.2.75.2 -- a variant swarm could fuel a winter surge

[Celerity]

Instead of a single new Greek letter variant, a group of immune-evading omicron spinoffs are popping up all over the world

https://www.washingtonpost.com/health/2022/10/18/covid-variants-xbb-bq1-bq11/

https://archive.ph/KMTqT

For two years, coronavirus variants emerged, one by one, sweeping the globe. But this fall and winter are expected to be different: Instead of a single ominous variant lurking on the horizon, experts are nervously eyeing a swarm of viruses — and a new evolutionary phase in the pandemic.

This time, it’s unlikely we will be barraged with a new collection of Greek alphabet variants. Instead, one or more of the multiple versions of the omicron variant that keep popping up could drive the next wave. They are different flavors of omicron, but eerily alike — adorned with a similar combination of mutations. Each new subvariant seems to outdo the last in its ability to dodge immune defenses. “It is this constant evolutionary arms race we’re having with this virus,” said Jonathan Abraham, an assistant professor of microbiology at Harvard Medical School.

The pace of evolution is so fast that many scientists depend on Twitter to keep up. A month ago, scientists were worried about BA.2.75, a variant that took off in South Asia and spawned a cloud of other concerning sublineages. In the United States, BA.4.6 and BF.7 have been slowly picking up steam. A few weeks ago, BQ.1.1 started to steal the spotlight — and still looks like a contender to take over this fall in Europe and North America. A lineage called XBB looms on the sidelines, and threatens to scramble the forecast.

Link to tweet

Link to tweet

To focus too much on any one possible variant is, many experts argue, missing the point. What matters is that all these new threats are accumulating mutations in similar spots in what’s called the receptor binding domain — a key spot in the spike protein where virus-blocking antibodies dock. If those antibodies can’t dock, they can’t block. Each new mutation gives the virus a leg up in avoiding this primary line of immune defense.

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The XBB family of Omicron has landed in the U.S. Here’s what it means for this fall’s COVID wave

https://fortune.com/well/2022/10/18/is-xbb-in-us-united-states-omicron-fall-covid-wave-bq1-bq11-new-york/



XBB—a new, extremely immune-evasive Omicron variant surging in Singapore—hasn’t yet been detected in the U.S. But its child has. XBB.1 was first detected in the U.S. on Sept. 15 and made up 0.26% of cases that were genetically sequenced over the past 15 days, Raj Rajnarayanan, assistant dean of research and associate professor at the New York Institute of Technology campus in Jonesboro, Ark., told Fortune. He cited data from GISAID, an international research organization that tracks changes in COVID and the flu virus.

Only 16 XBB.1 cases have been detected in the U.S. so far, and most have been found in New York—considered a bellwether state because of its volume of incoming international travelers and robust genetic sequencing capabilities, Rajnarayanan said. XBB is a combination of two different Omicron spawns. It, along with BQ.1.1, is considered to be the most immune-evasive COVID variant so far, surpassing the immune-evasiveness of shared ancestor BA.5, which was dominant around the globe this summer.

Scientists, including top U.S. infectious disease expert Dr. Anthony Fauci, expect a fall and winter wave of cases in the U.S. that begins to surge in October and peaks in January. It’s still unclear which COVID variant may fuel that wave. On Friday the U.S. Centers for Disease Control and Prevention announced that heavyweight Omicron spawn BQ.1 and BQ.1.1 are in the U.S., and quickly rising. With XBB present as well, the scene has been set for a potential battle royal between two formidable variants.

Compared to XBB, XBB.1 features just “one small change” to the spike protein, which the virus uses to attach to and infect cells. The impact of the alteration is unknown, according to Rajnarayanan. It’s one of multiple XBB offspring being eyed by variant trackers globally that are helping fuel Singapore’s wave—despite a significantly vaccinated and boostered population.

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