The latest version of COVID-19 to raise concern is XBB.1.5 — an omicron subvariant that has spread rapidly in the US and accounts for a growing number of COVID-19 cases. Scientists are keeping a close eye on it because they believe it may be the most transmissible variant to date.
It hasn’t grown quite as fast as the US Centers for Disease Control had previously reported, however. On Friday, the agency revised downward its estimate of the subvariant’s share of share of cases in the US, moving it down from 40% to 18% of COVID-19 cases in the week ending Dec. 31.
The most current data — for the week ending Jan. 7 — estimates that XBB.1.5 now makes up about 28% of cases. The CDC notes in its data collection that variant proportions are “model projections” and might differ from weighted estimates that come later.
Even with that update, XBB.1.5’s growth in the US is rapid and on track to outcompete BQ.1 and BQ.1.1, also subvariants of the “original” omicron variant. Together, BQ.1 and BQ.1.1 accounted for 56% of cases in the week ending Jan. 7.
As with all new versions of COVID-19, we’ll need more time to see how XBB.1.5 plays out in the US population. Hospitalization rates and deaths from COVID-19 have risen in recent days and weeks, though in much lower numbers compared with earlier spikes of the disease.
The antiviral Paxlovid remains available for people at higher risk of getting severely ill, and adults in their 50s or up and people with chronic health conditions should talk to a health care provider if they test positive or think they have COVID-19.
Here’s what we know about XBB.1.5.
What is XBB.1.5?
XBB.1.5 is part of the same family as the “original” omicron variant, which keeps mutating into more contagious versions of itself. XBB.1.5 comes from the XBB family, more specifically, and has mutations that may make it more able to evade immunity, according to a Jan. 6 post from the Johns Hopkins Bloomberg School of Public Health.
For roughly a year, the omicron variant has been dominant. Omicron, delta, alpha and earlier strains of COVID-19 were given their own Greek alphabet label and separate distinction as variants of concern because they proved troublesome enough to scientists in the way they evade vaccine immunity, cause more severe illness or create more serious problems. By contrast, although BA.5 was extremely contagious and caused more reinfections in people who already had COVID-19, it didn’t necessitate a big enough change in our public health response to get its own name from the WHO, according to classification logic.
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Will vaccines and treatments work against new subvariants?
More time is needed to assess XBB.1.5 and how well the vaccines neutralize the newer version of the virus. However, White House COVID-19 response coordinator Dr. Ashish Jha warned on Twitter earlier this month that if you were last infected with COVID-19 before July or if you never got the new bivalent booster that became available in September, you have a good chance of getting infected with this new strain of the virus.
According to the Jan. 6 post from the Johns Hopkins Bloomberg School of Public Health, which referenced information from virologist Andy Pekosz, someone who was infected with another version of omicron may be susceptible to reinfection with XXB.1.5 because it’s more immune evasive.
Vaccines continue to be protective against severe disease as the virus mutates, which includes the bivalent boosters currently available. In August, unvaccinated adults of all ages were over five times more likely to die from COVID-19 compared to adults aged 18 and up who were up to date on their shots.
BQ.1 and BQ.1.1 have outflanked COVID-19 monoclonal antibody treatments
Monoclonal antibody treatments, including Evusheld for immunocompromised patients, will likely no longer work against BQ.1 or BQ.1.1, according to a Dec. 28 update from the National Institutes of Health. Bebtelovimab, which is the monoclonal antibody made by Eli Lilly, also doesn’t work against the more recent dominant subvariants of COVID-19, and the FDA revoked its authorization in the US on Nov. 30. Other monoclonal antibody treatments were removed from the US market earlier in the pandemic as the virus rendered them ineffective.
There’s no indication that Paxlovid, an antiviral that higher risk patients can take in the first few days of their illness, won’t work against the newer forms of omicron. If you believe you’re at higher risk of getting severely ill from COVID-19, reach out to your doctor or pharmacist right away after testing positive for COVID-19 or experiencing symptoms to determine your treatment options.
The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.
