The U.S. Food and Drug Administration authorized booster shots of Pfizer-BioNTech's COVID-19 vaccine in children between ages 12 and 15 on Monday.

Booster shots have been touted as a key tool in fighting the surge in COVID cases linked to the omicron variant, which has shown an ability to -- at least partially -- evade protection offered by two doses.

The FDA also shortened the wait period for adults and adolescents to receive boosters from six months down to five months.

In addition, the agency authorized COVID booster shots for children aged five to 11 who are immunocompromised.

"Mrs. Doubtfire the Musical" has becomes the latest Broadway show to announce it is pausing performances amid the rapidly rising number of COVID-19 cases in New York City.

In a post shared on Twitter, producers announced the musical will "be taking a hiatus" between Jan. 10 and March 14.

Anyone with tickets for performances during the hiatus can either exchange for performances after March 15 or request a refund.

Puerto Rico's COVID-19 positivity rate spiked to 33% on Monday, according to the island’s health department COVID dashboard.

This is a 16-fold jump from the 2% positivity rate reported just two weeks ago, which was a record low.

Scientist Mónica Feliú-Mójer from Ciencia PR, an organization that focuses on scientific education in Puerto Rico, said the rapid increase is due to many factors, including people's behavior.

She said people gathering over the holidays, while a highly transmissible variant continued to spread, led to the spike in the positivity rate.

“The holidays are culturally very, very important and everyone thought this would be a different Christmas. People were eager to get together,” Feliú-Mójer told ABC News.

Read more here.

-ABC News' Cristina Corujo

South Korea on Monday reported the deaths of two patients in their 90s who tested positive for omicron.

Both were receiving treatment in Gwangju, about 200 miles south of Seoul, the semi-official Yonhap News Agency said.

South Korean health officials reported 111 new omicron cases on Monday, bringing its total to 1,318 omicron cases.

About 83% of South Korea's population has been fully vaccinated, according to the Korea Disease Control and Prevention Agency. About 36% received a booster.

The state of New York has told 40 hospitals they must turn away nonessential, nonurgent elective surgeries for the next two weeks in response to low bed capacity. Most of the hospitals are located in upstate New York.

The determination was made after the hospital locations were added to the list of "high risk regions" by the state department of health due to 90% of beds being occupied according to the seven-day average.

"We will use every available tool to help ensure that hospitals can manage the COVID-19 winter surge," acting State Health Commissioner Dr. Mary Bassett said in a statement Saturday. "I want to remind New Yorkers that getting vaccinated and boosted remain the best way to protect against serious illness and hospitalization from COVID-19. Vaccination also protects our hospital system. We cannot return to the early months of the pandemic when hospitals were overwhelmed."

All of the hospitals in three regions -- Mohawk Valley, Finger Lakes and Central New York -- are included in those 40 facilities.