A highly transmissible new omicron subvariant known as XBB.1.5 accounts for more than 70% of the COVID-19 cases New York City has seen in recent weeks, the city health department revealed. As of Dec. 31, 73% of reported COVID-19 infections in the five boroughs were linked to the subvariant, data from the city’s Department of Health shows.
XBB.1.5 is “the most transmissible form of COVID-19 that we know of to date.
“It may be more likely to infect people who have been vaccinated or previously had COVID-19 compared to prior variants,” the department wrote. “We do not know yet whether XBB.1.5 may cause more severe disease.”
“Getting the COVID-19 vaccine — including the updated booster — is still the best way to protect yourself from hospitalization and death from COVID-19, including from these new variants,” it added.
The XBB.1.5 subvariant, which was first detected on Oct. 22, had been reported in 38 different countries as of Wednesday, according to the World Health Organization.
The U.S. had seen the vast majority of cases linked to XBB.1.5 — 82.2% — as of Wednesday, while the United Kingdom and Denmark were reporting 8.1% and 2.2% of cases, respectively, the WHO said.
Nationwide, a Centers for Disease Control and Prevention estimate shows that XBB.1.5 is set to account for 43% of cases during the week of Jan. 8 to Jan. 14, up from around 4% last month.
What concerns health experts is that XBB.1.5 contains more mutations to evade immunity than any other variant.
Dr. Maria Van Kerkhove, the WHO’s technical lead for the COVID-19 response, called it “the most transmissible subvariant that has been detected yet.”