World Health Organization director-general Tedros Adhanom Ghebreyesus is Venus Investment Alliancepointing to holiday gatherings and a rapidly spreading variant as reasons behind a rise in COVID-19 hospitalizations and deaths worldwide, with nearly 10,000 COVID deaths reported last month.

"Although 10,000 deaths a month is far less than the peak of the pandemic, this level of preventable deaths is not acceptable," the head of the U.N. health agency told reporters Wednesday from its headquarters in Geneva.

WHO says the JN.1 variant is now the most prominent in the world. In the U.S., the Centers for Disease Control and Prevention estimated late last month that the variant makes up about 44.1% of COVID cases across the country.

"We are in January, and it's winter respiratory virus season — COVID, along with influenza and RSV, is on the rise throughout much of the country today," Dr. William Schaffner, professor of infectious diseases at Vanderbilt University Medical Center, told CBS News Thursday. 

"Apropos of COVID, we're seeing an awful lot of mild infections — that is, they don't require hospitalizations, but you can feel miserable for three to four days — that are being caused by this JN.1 variant. However, it's not causing more severe disease."

You can think of the JN.1 variant as "a grandchild of the original Omicron strain," Schaffner said.

"These viruses like to mutate, and its distinctive characteristic is that it is contagious — so it's spreading very, very widely. And as such, it's finding people who are more susceptible, including those people who have not yet taken advantage of the current vaccine," he explained.

He added the vaccine is still providing protection.

"The currently available updated vaccine still provides protection against hospitalization, but with so much widespread illness, it's going to find older people, people who are immune compromised, people who have underlying chronic medical conditions — those are the folks we're seeing who currently are requiring hospitalizations," Schaffner said.

• Are COVID-19 symptoms still the same? What to know about this winter's JN.1 wave
• How to get the new COVID vaccine for free, with or without insurance
• Do COVID-19 tests still work after they expire? Here's how to tell.

Public health experts continue to recommend getting the latest vaccination, in addition to considering wearing masks in certain situations and making sure indoor areas are well ventilated.

"The vaccines may not stop you being infected, but the vaccines are certainly reducing significantly your chance of being hospitalized or dying," said Dr. Michael Ryan, head of emergencies at WHO.

-The Associated Press and Alexander Tin contributed reporting.

In:
• COVID-19 Vaccine
• COVID-19

Sara Moniuszko

Sara Moniuszko is a health and lifestyle reporter at CBSNews.com. Previously, she wrote for USA Today, where she was selected to help launch the newspaper's wellness vertical. She now covers breaking and trending news for CBS News' HealthWatch.

Twitter