Los Angeles Mayor Eric Garcetti said Thursday he is quarantining after his 9-year-old daughter tested positive for COVID-19.

During a COVID-19 update, the mayor said that he and his wife have tested negative for the virus, and his daughter has mild symptoms.

Garcetti, who gave his update live from his home instead of his usual podium at City Hall, said he has no idea how his daughter contracted the virus.

"We follow very strict protocols in our household," he said. "We haven't mixed households. There's no behavior that she has engaged in that doesn't adhere strictly to the protocols of our health officials."

The numbers in LA right now are alarming, Garcetti said, as city test sites are seeing a seven-day positivity rate of 19.6%; some have a positivity rate higher than 30%.

Intensive care unit capacity in the region is at 0%. Beds can be added, he said, but there's also a staffing shortage. There are currently 5,100 people hospitalized in Los Angeles County, 1,035 of them in ICUs.

"There are more people in the ICU today than all COVID-19 hospitalizations about a month ago," Garcetti said.

-ABC News' Lauren Botchan contributed to this report.

A panel of independent experts voted 20 to 0 to recommend Moderna's COVID-19 vaccine for emergency use authorization. One person abstained in Thursday's vote.

The U.S. Food and Drug Administration advisory committee voted yes on the following question: "Based on the totality of scientific evidence available, do the benefits of the Moderna COVID-19 Vaccine outweigh its risks for use in individuals 18 years of age and older?"

The committee's recommendation now goes back to the FDA, which will discuss any issues raised in the meeting and finalize a decision about emergency authorization.

If an EUA is issued, a Centers for Disease Control and Prevention advisory committee will meet Friday to discuss recommendations for who should take the Moderna vaccine.

The FDA authorized the first COVID-19 vaccine, from Pfizer-BioNTech, last Friday.

-ABC News' Stephanie Ebbs

An Alaska health care worker was hospitalized Wednesday, shortly after receiving the Pfizer/BioNTech COVID-19 vaccine.

The unnamed staff member at Bartlett Regional Hospital in Juneau, Alaska, "showed signs of an anaphylactic reaction" 10 minutes after inoculation, "with increased heartbeat, shortness of breath and skin rash and redness," according to a press release.

"She was given epinephrine and Benadryl, admitted to the hospital, and put on an intravenous epinephrine drip," Bartlett Regional Hospital said in a statement Wednesday night. "Her reaction was serious but not life threatening."

The staff member, who had no known previous allergies or adverse reactions to vaccines, "is recovering and will remain another night in the hospital under observation," according to the press release. She was released from the hospital Thursday morning.

"She is still encouraging her colleagues to get the vaccine," the hospital said.

It's the first known adverse allergic reaction to the COVID-19 vaccine developed by U.S. pharmaceutical giant Pfizer and its German partner BioNTech, which was granted emergency-use authorization in the United States last Friday.

A second staff member at Bartlett Regional Hospital "experienced eye puffiness, light headedness, and scratchy throat" 10 minutes after being injected with the Pfizer/BioNTech vaccine on Wednesday, according to the press release.

"His reaction was not considered anaphylaxis," Bartlett Regional Hospital said in the statement Wednesday night. "He was taken to the Emergency Department and administered epinephrine, Pepcid and Benadryl. He felt completely back to normal within an hour and was released."

"He too does not want his experience to have a negative impact on his colleagues lining up for the vaccine," the hospital added.

Both incidents were reported to the U.S. Centers for Disease Control and Prevention, which Bartlett Regional Hospital said "is providing guidance and support." The symptoms in each case were discovered during the 15-minute observation period after inoculation recommended by the CDC.

“We were expecting these things and we had all the right systems in place,” Charlee Gribbon, an infection control practitioner at Bartlett Regional Hospital, who is overseeing a mass operation to vaccinate as many staff as possible, said in a statement Wednesday night.

Alaska’s Chief Medical Officer Anne Zink said there are "no plans to change our vaccine schedule, dosing or regimen."

Southern California's intensive care unit capacity fell to 0% on Thursday.

The state’s San Joaquin Valley region, which spent many days at 0.0%, is now reporting 0.7% ICU capacity.

California Gov. Gavin Newsom has ordered regions to issue a stay-at-home order for at least three weeks if their ICU capacity falls below 15%. The Bay Area’s ICU capacity has fallen to 13.1% and will begin its stay-at-home order Thursday. The Greater Sacramento area, where ICU capacity is at 11.3%, is also under a stay-at-home order. Northern California is the state’s only region not under the order.

California reported 52,281 new daily cases on Thursday, close to the record high set one day ago.

If California were a country, it would have more daily COVID-19 cases than the U.K., India, France, Italy, and Mexico.

On Wednesday, the Golden State reported a record 53,711 new cases.

ABC News' Bonnie Mclean and Matt Fuhrman contributed to this report.