COVID-19 live updates: City sees fourfold increase in pediatric hospitalizations

New studies are offering additional reassurance that AstraZeneca's monoclonal antibody drug works against omicron.

The company's EVUSHELD retains neutralization activity against omicron, according to "live" virus neutralization data from both University College Oxford and Washington University School of Medicine.

AstraZeneca announced last week that its antibody drug would likely retain protection against omicron. These studies add to that growing evidence.

AstraZeneca's monoclonal antibody was authorized on Dec. 8, but for a narrow group of people. It is authorized as a way to prevent COVID-19 among people who are immune compromised, or people who are allergic to vaccine components. It is not authorized as a way to treat COVID-19 among people who have already tested positive.

There are three monoclonal antibody treatments currently authorized to treat people who already have COVID-19. Two of those treatments -- those made by Eli Lilly and Regeneron -- appear to have very little activity against omicron. A third treatment, made by Vir and GlaxoSmithKline, appears to work against omicron but is currently in short supply. The companies are working to scale up production.

-ABC News' Sony Salzman

A Royal Caribbean ship has been blocked from entering Curacao and Aruba after 55 crew members and guests tested positive for COVID-19.

The ship, named Odyssey of the Sea, set sail from Florida on Dec. 18 and had planned to visit the Caribbean  for eight nights.

According to the cruise line, 95% of all people onboard were fully vaccinated. The crew and guests who tested positive were all “fully vaccinated and mildly symptomatic or asymptomatic.”

Close contacts of the positive patients have been placed in quarantine and will be monitored for 24 hours prior to testing.

The ship will remain at sea and is scheduled to return to Florida on Dec. 26.

-ABC News’ Mina Kaji

The Food and Drug Administration authorized Merck's COVID-19 pill Thursday for certain patients.

The authorization is specifically for adults who are at high-risk for severe illness and don’t have access to other FDA-authorized treatments. 

This is the second COVID-19 therapy available in pill form after Pfizer’s pill was authorized in patients aged 12 and older on Wednesday.

Children and teenagers are not eligible for Merck’s pill due to fears that the medication could negatively impact bone and cartilage growth. 

COVID-19 patients seeking the pills must obtain a doctor’s prescription first.

-ABC News’ Sony Salzman

Rep. Jan Schakowsky, D-Ill., has tested positive for COVID-19.  

Schakowsky said her husband, Bob, had tested positive last week. After several negative tests, the lawmaker also tested positive on Tuesday night, she said on Twitter.

Both Schakowskys were vaccinated and received boosters. They're now quarantining, she said.

"We got tested when we felt something was off, and now we can prevent exposure to our family and loved ones," Schakowsky said. "I implore you to do the same before holiday gatherings this week and next. Get tested if you feel sick or have been around someone who tests positive."

-ABC News's Ben Siegel