A new, stealthy coronavirus variant is spreading fast, spooking scientists and Wall Street analysts, but experts say there is cause for optimism
- XBB is a new version of Omicron that is evading existing treatments and immunity.
- It is spreading quickly in Singapore, and virus-watchers are worried it could spread in the US.
As Halloween approaches, murmurs of another "nightmare" COVID variant on the way are spooking reporters and Wall Street analysts alike.
The new variant is called XBB, and it's already triggering a new wave of infections and hospitalizations in some south Asian countries, including India and Singapore.
XBB is just one of "multiple more-immune evasive Omicron subvariants on the rise around the world," infectious disease expert Dr. Celine Gounder, a Senior Fellow at the Kaiser Family Foundation, told Insider.
But "among the new variants, XBB has the most significant immune evasion properties," market forecasters at Morgan Stanley said Thursday in a memo.
Given that we've now seen nearly three full years of COVID variants — and nearly a year of different Omicrons before XBB emerged from them — how worried, really, should we be about this new version of the virus?
Experts say we should expect many more infections this fall and winter, including infections in vaccinated, boosted Americans. But there are some simple things you can do to prepare to battle XBB and other evasive COVID variants on the horizon.
What is XBB?
XBB is a recombinant variant – meaning that it's a combination of two other BA.2 Omicron subvariants (specifically, BA.2.10.1 + BA.2.75).
Like other Omicrons we've seen before, XBB is "finding ways to evade the way we get immunity from vaccines and previous infection, with changes on the spike protein," UC Berkeley infectious disease expert John Swartzberg told the San Francisco Chronicle.
It remains to be seen whether XBB will actually dominate the landscape of US COVID infections this winter, or whether it'll just be one option among the wide buffet of Omicron subvariants.
So far, it's not even making a dent on the radar of US virus watchers, compared to other Omicrons. It's possible that the BA.5 subvariant, BQ.1.1., which is already on the rise in Europe, may turn out to be more of a concern for Americans than XBB ever will.
Professor Moritz Gerstung, a computational biologist in Germany, said recently on Twitter that we might be in for a "tight race" between BQ.1.1 and XBB for the next few months. Both have a slight growth advantage over BA.5, which is the dominant version of COVID right now in the US.
Why is everyone freaking out about XBB?
In Singapore, reinfections and hospitalizations are both up, driven by XBB — though local trends suggest that this version of the virus may also be somewhat milder than BA.5, with a 30% lower risk of hospitalization.
Both XBB and BQ.1.1 are also showing resistance to monoclonal antibodies, a treatment used for COVID patients.
That is why Gounder insists that, whatever happens next, "it's really important for those at the highest risk, including people 50 and over, and people who are immunocompromised, to get boosted right away if they haven't already been this fall."
The new bivalent booster shots should hold up against XBB
Remember: this is still Omicron, and the new boosts from Pfizer and Moderna target BA.4 and BA.5, which are related to XBB.
That means existing vaccines should still "protect against severe disease, hospitalization, and death," Gounder said. "But I expect a lot of breakthrough infections despite vaccination" in the coming winter months, she added, whether that's with XBB, or some other evasive new variant.
According to CDC data, fewer than 15 million Americans have gotten an updated booster so far this fall – that's less than 5% of the country, so there is room for improvement both with:
Gounder said she knows Americans are tired of mitigation measures, but says "high-quality masks will be important for reducing transmission, especially in indoor public spaces" this winter.