XBB, the new so-called "nightmare" COVID-19 variant, is spreading rapidly in parts of the world and has already made its way to the U.S., researchers say.
XBB is a variant of omicron and has been dubbed the "nightmare variant" in Singapore. It is extremely immune evasive and has also shown that it might be immune to current vaccines.
WATCH ANYTIME FOR FREE
 |
Stream NBC10 Boston news for free, 24/7, wherever you are. |
"The XBB variant wave in Singapore will soon be their 2nd worst for the pandemic," Dr. Eric Topol, founder of the Scripps Research Translational Institute, tweeted. "The reinfection rate prior to the wave was 5% and now up to 17%, which tells us about the immune escape properties of this variant (akin to BQ.1.1, very high level of immune evasion)"
Get updates on what's happening in Boston to your inbox. Sign up for our News Headlines newsletter.
According to Fortune, XBB was first detected in the U.S. on Sept. 15. It is not yet widespread, as only 16 cases have been reported here, mostly in New York.
The CDC's latest update on the prevalence of COVID variants shows no signs of XBB yet in New England, as BA.5, BA.4.6 and the new BQ.1.1 and BQ.1 variants continue to dominate. But throughout the pandemic, COVID numbers in New York have often provided an early look at what Massachusetts and the other southern New England states have in store.
Dr. Maria Van Kerkhove, an infectious disease specialist who serves as the technical lead for COVID-19 response at the World Health Organization, posted a video to Twitter on Wednesday to address growing concerns about the XBB variant. She said XBB is a "recombinant" of two BA.2 sublineages, BA.2.10.1 and BA.2.10.75.
"We do know this recombinant has a significant growth advantage. All of the subvariants of omicron are showing increased transmissibility and properties of immune escape," she said. "With this XBB recombinant we have one study based on a pseudo virus, so not a live virus, that is analyzing antibody escape and it's showing significant immune evasion. And this is of concern for us because we need to ensure that the vaccines that are in use worldwide will remain effective at preventing severe disease and death."
Van Kerkhove said there have been no signs of increased severity in XBB and BQ.1.1 and BQ.1 variants, "but it's very early and we have very little data to assess this."
"We need to be prepared for this," she said. "Countries need to be in a position to conduct surveillance, deal with increases in cases and perhaps deal with an increase in hospitalizations. We don't see a change in severity yet and our vaccines remain effective, but we have to remain vigilant."
Across New England, COVID cases have started to creep up in recent weeks. Massachusetts health officials reported 7,865 new COVID-19 cases and 60 new deaths in last week's report. The state's seven-day average positivity was listed at 8.60% last week, compared to 7.76% the week before. Updated statewide COVID data is set to be released Thursday afternoon.
The CDC's COVID risk level has also been streadily rising across southern New England of late, with all of Connecticut, Massachusetts and Rhode Island now included in the medium risk category.
While doctors interviewed by NBC10 Boston this week said they expect some level of a winter surge, they said there isn't any data yet to suggest that the new variants will cause more severe disease.
"Only time will tell," Dr. Sabrina Assoumou of Boston Medical Center said. "My big message is, unfortunately, we're seeing more variants, and the virus is actually figuring out better ways to evade our protection, but we're not hopeless and it's not a helpless situation. We have vaccines, they actually work, but the key thing is that you have to be up to date... So please get get up to date so that we are all prepared in the community before a potential winter surge."
"I think it's likely that we'll continue to see the proportion of cases that are being caused by the new variants increase because they do seem to be able to evade immunity," added Dr. Daniel Kuritzkes of Brigham and Women's Hospital. "But for the general public. I think the issue is going to be that, first of all, receiving a booster vaccine, as Dr. Assoumou said, will strengthen immunity because even if this variant can get around the antibodies and may get people infected and give them a cold, they're not going to have anything much worse than an upper respiratory infection if they've been recently boosted because there does seem to be much broader cross protection across all of these variants for severe disease and that's a really important point.
