The XBB.1.5 omicron subvariant that became dominant in the U.S. last week has gained more ground, according to data from the nation’s main health agency, accounting for 49.1% of new cases in the latest week, up from 43% a week ago.

The subvariant is pulling further ahead of BQ.1.1 and BQ.1, the former dominant strains of the coronavirus that causes COVID, according to the data from the Centers for Disease Control and Prevention.

BQ.1.1 accounted for 26.9% of new cases, down from 28.8% a week ago, while BQ.1 accounted for 13.3%, down from 15.9% a week ago.

In the New York region, which includes New Jersey, Puerto Rico and the U.S. Virgin Islands, XBB.1.5 accounted for 86.8% of new cases, up from 82.7% a week ago.

The World Health Organization has acknowledged that XBB.1.5, which was first detected in tiny numbers in the U.S. in October, has become the most transmissible variant yet thanks to a growth advantage. The agency said that it appears to have a greater ability to evade immunity than earlier variants.

In its weekly epidemiological update, the agency said the XBB line is one of four omicron subvariants that are showing transmission advantage over other circulating variants. The other three are BF.7, BQ.1 and BA.2.75.

For now, the WHO said it has no additional data on XBB.1.5, but BA.2.75.2 is showing the most neutralization resistance to sera from vaccinated and COVID-infected patients.

In the U.S., the seven-day average of new COVID cases stood at 50,839 on Thursday, according to a New York Times tracker. That’s down 20% from two weeks ago and below the recent peak of 70,508 on Christmas Eve.

The daily average for hospitalizations was down 18% at 39,272. The average for deaths was 498, up 5% from two weeks ago. 

Cases are rising in just six states, as well as the U.S. Virgin Islands, Washington, D.C., and Puerto Rico, a significant improvement from recent trends. On a per capita basis, Illinois now has the most cases at 31 per 100,000 residents, followed by Kentucky at 30 and Rhode Island at 27.

See also: Americans are facing years of ‘tripledemic’ winters that may put patients with other ailments at risk, Jha says

Coronavirus Update: MarketWatch’s daily roundup has been curating and reporting all the latest developments every weekday since the coronavirus pandemic began

Other COVID-19 news you should know about:

• Japanese Prime Minister Fumio Kishida on Friday announced plans to downgrade the legal status of COVID-19 to the equivalent of seasonal influenza in the spring, a move that would further relax mask requirements and other preventive measures as the country seeks to return to normalcy, the Associated Press reported. Kishida said he has instructed experts and government officials to discuss the details on changing the status of COVID-19. A change would also remove self-isolation rules and other antivirus requirements and allow COVID-19 patients to seek treatment at any hospital instead of restricting them to specialized facilities.

Read also: Moderna is the latest company to produce a promising RSV vaccine

• As Chinese people crowd onto trains and buses ahead of the Lunar New Year holiday, which begins on Jan. 21, officials are playing down fears that widespread travel over the popular family holiday will lead to a spreader event, Reuters reported. In comments reported by state media late Thursday, Vice Premier Sun Chunlan said the virus was at a “relatively low” level, while health officials said the number of COVID patients in the hospital and in critical condition was on the decline. But there are doubts about China’s official account of an outbreak that has overwhelmed hospitals and funeral homes since Beijing abandoned strict COVID controls and mass testing last month.

What’s seen as the world’s largest annual human migration is under way again in China for the Lunar New Year after the country lifted pandemic restrictions. The Wall Street Journal’s Yoko Kubota reports on how it’s expected to boost the economy — and the risk of new COVID-19 outbreaks. Photo: Cfoto/Zuma Press

• CureVac’s
promising Phase 1 data for flu and COVID-19 vaccine candidates is a signal to investors that its messenger RNA technology is competitive, according to UBS Securities analysts, who upgraded the company’s stock to buy from neutral on Thursday, as MarketWatch’s Jaimy Lee reported. They also more than doubled the price target, to $18 from $8. CureVac had attempted to develop a first-generation COVID vaccine but failed. “As the first data of the 2nd-gen platform’s immunogenicity in humans, this is a major inflection point for the story, and suggests potentially competitive mRNA platform relative to mRNA peers,” the analysts wrote.

Here’s what the numbers say:

The global tally of confirmed cases of COVID-19 topped 668.3 million on Thursday, while the death toll rose above 6.73 million, according to data aggregated by Johns Hopkins University.

The U.S. leads the world with 101.9 million cases and 1,103,681 fatalities.

The Centers for Disease Control and Prevention’s tracker shows that 229.5 million people living in the U.S., equal to 69.1% of the total population, are fully vaccinated, meaning they have had their primary shots.

So far, just 50.7 million Americans, equal to 15.3% of the overall population, have had the updated COVID booster that targets both the original virus and the omicron variants.