More children and teens are being hospitalized for COVID-19 in New York City and the surrounding area than at any other time this year, data from the state health department shows. The vast majority of those hospitalized are unvaccinated, according to a health advisory issued by the department on December 24th.

In the week leading up to Christmas, hospitals in and around New York City had an average of about 73 pediatric COVID patients each day — up from just 18 per day at the start of the month. On December 23rd alone, 115 COVID-positive young people spent the day in the hospital.

Half of the children hospitalized in the last week were too young to be vaccinated, state officials said. None of the hospitalized 5- to 11-year olds were fully vaccinated, and just a quarter of the hospitalized 12- to 17-year-olds had received a full course of vaccines.

Citywide, 15% of 5- to 11-year-olds and 71% of 12- to 17-year olds are fully vaccinated, according to state data. Older teens are also eligible to receive a booster shot, although it’s not clear how many in NYC have opted for the additional dose.

Completing a course of vaccinations dramatically reduces a person’s odds of being hospitalized with COVID-19, and a booster offers additional protection, studies show.

The state health department did not return a request for comment, and the city health department declined to comment.

COVID cases have spiked for all age groups this month, thanks in part to the highly transmissible omicron variant. On December 23rd — the most recent day for which data was made available — more than 27,000 New Yorkers tested positive for the virus. That’s the highest single-day case count reported for the city since the pandemic began.

Widespread COVID transmission shut down a dozen schools and completely or partially closed thousands of classrooms in the weeks leading up to the holiday break.

On Wednesday, the United Federation of Teachers criticized the education department’s onsite COVID testing program, which samples only a small percentage of students and makes it difficult for staff to participate.

All education department staff are required to be fully vaccinated—but more than a month after the deadline, the city has not yet called on workers to provide proof of their second dose, the New York Post reported.

In a written response to WNYC, the Department of Education said only a “fraction” of staff members had yet to upload verification of their second dose to the department’s vaccination portal. It said a failure to do so did not necessarily mean a member of staff hadn’t received their second dose.

However, the department did not respond to repeated questions asking for exact figures on how many teachers and other staff had yet to show proof that they are considered fully vaccinated.