IE 11 is not supported. For an optimal experience visit our site on another browser.

Nov. 23 Coronavirus updates: Positive cases spread in sports, Ohio reports 11,000 new cases

November 23 news about the coronavirus pandemic. Ohio reported 11,000 more cases as multiple members of the Baltimore Ravens tested positive.
Image: Outbreak of the coronavirus disease (COVID-19), in Brazil
Medical workers take care of a patient at the intensive care unit in a hospital in Porto Alegre, Brazil, on Nov. 19. Diego Vara / Reuters

This live blog has ended, click here for NBC News' continuing coverage of Covid-19.

Pharmaceutical company AstraZeneca said Monday late-stage trials of its Covid-19 vaccine, developed in conjunction with U.K.'s University of Oxford, have shown it to be “highly effective.”

The results are the third promising vaccine breakthrough in the fight against the coronavirus. Earlier this month, Pfizer and Moderna reported preliminary results from late-stage trials, showing that their vaccine candidates were almost 95 percent effective.

The latest Covid-19 data and coverage:

Pandemic's toll on mental health accentuated in cities

Covid-19 hasn't been the only catastrophe sweeping the country this year.

Health experts say Americans are experiencing symptoms of anxiety and depression made worse by pandemic-related stressors, including job loss, evictions, remote learning, travel restrictions and limits on gathering.

The contentious presidential election, increased racial tensions and natural disasters, in addition to Covid-19, added to Americans' stressors, said Dr. Joshua Gordon, director of the National Institute of Mental Health.

Click here to read the full story.

TSA screened 2 million people Friday and Saturday, despite CDC warning against travel

The Transportation Security Administration screened more than 2 million passengers on Friday and Saturday, despite a warning from the Centers for Disease Control and Prevention to avoid holiday travel.

While the TSA has screened an average of 1 million people a day since March, Friday was just the second day over 1 million.

The CDC's announcement last week was a "recommendation for the American public to consider," said Dr. Henry Walke, the CDC's Covid-19 incident manager. "We're seeing ... exponential growth in cases, and the opportunity to translocate disease or infection from one part of the country to another, it leads to our recommendation to avoid travel at this time."

When multiple households gather, cases of Covid-19 rise dramatically, studies have shown. Spikes occurred after Memorial Day, the 4th of July and Labor Day.

Thanksgiving — the most heavily traveled holiday in the U.S. — is a particular challenge, and colder weather across much of the country means family gatherings will likely be held indoors. The holiday also comes as average daily cases are higher than at any point in the pandemic.

Russia sets new daily Covid record

A medical worker wearing protective gear enters the treatment hall of a temporary hospital for coronavirus patients in the Krylatskoye Ice Palace in Moscow on Nov. 18. Pavel Golovkin / AP

MOSCOW — Daily new coronavirus infections in Russia hit a new high on Monday, with authorities reporting a record 25,173 new cases. The latest figure brings the country’s total to over 2.1 million. The government coronavirus task force also reported 361 deaths on Monday, raising the total since the start of the pandemic to 36,500.

Russia, which currently has the world's fifth-largest number of confirmed cases, has been swept by a rapid coronavirus resurgence since September. Despite this, authorities insist there are no plans to impose a second lockdown or to shut businesses nationwide.

Hong Kong warns situation 'worsening rapidly'

People wait outside a Covid testing center Sunday in Hong Kong. Peter Parks / AFP - Getty Images

HONG KONG — Hong Kong reported 73 new coronavirus cases on Monday as the government warned the epidemic in the densely populated city is rapidly getting worse with silent transmission chains feared amid a rise in asymptomatic infections.

The Chinese-ruled city has so far managed to avoid the widespread outbreak of the disease seen in many major cities across the world, with numbers on a daily basis mostly in single digits or low double digits in recent weeks.

Many of the latest cases are linked to dance clubs and the government has appealed to residents in affected areas to take a Covid-19 test to help contain the outbreak. Mobile testing stations have been set up in several districts.

"The local epidemic situation is worsening rapidly," the government said in a statement. "Some of the confirmed cases are asymptomatic and this has indicated the existence of many silent transmission chains in the community."

UK regulator will make vaccine decision in 'shortest time possible'

LONDON - Britain medicine regulator said on Monday it would aim to make a decision on Pfizer and BioNTech's Covid-19 vaccine candidate "in the shortest time possible" after receiving additional data about the shot.

"It is our job now to rigorously assess these data and the evidence submitted on the vaccine’s safety, quality and effectiveness," said June Raine, chief executive of Britain's Medicines and Healthcare products Regulatory Agency.

"As we have received this data through a rolling review, we have already started our analysis and will aim to make a decision in the shortest time possible, without compromising the thoroughness of our review."

California governor in quarantine with family after kids exposed to Covid-19

California Gov. Gavin Newsom is quarantining with his family after three of his four children were exposed to a patrol officer who tested positive for Covid-19, he said in a tweet late Sunday.

Newsom said that he and his wife, Jennifer Siebel Newsom, learned on Friday evening of his children’s exposure to the officer from the California Highway Patrol. He and his wife were not exposed, he said.

The family tested negative on Sunday and they will be quarantined for 14 days.

California has seen a rise in Covid-19 cases and enacted a curfew on Saturday for the vast majority of its counties. The stay at home order requires nonessential work, movement and gatherings to stop from 10 p.m. to 5 a.m.

China tests millions after coronavirus flare-ups in 3 cities

BEIJING — Chinese authorities are testing millions of people, imposing lockdowns and shutting down schools after multiple locally transmitted coronavirus cases were discovered in three cities across the country last week.

As temperatures drop, large-scale measures are being enacted in the cities of Tianjin, Shanghai and Manzhouli, despite the low number of new cases compared to the United States and other countries that are seeing new waves of infections.

Many experts and government officials have warned that the chance of the virus spreading will be greater during the cold weather. Recent flare-ups have shown that there is still a risk of the virus returning, despite being largely controlled within China.

On Monday, the National Health Commission reported two new locally transmitted cases in Shanghai over the last 24 hours, bringing the total to seven since Friday. China has recorded 86,442 total cases and 4,634 deaths since the virus was first detected in the central Chinese city of Wuhan late last year.

AstraZeneca says its coronavirus vaccine can be around 90 percent effective

LONDON — British pharmaceutical giant AstraZeneca said on Monday that its vaccine for Covid-19 could be up to 90 percent effective in preventing the disease — the third promising breakthrough in the fight against a pandemic that has killed nearly 1.4 million people worldwide.

“This vaccine’s efficacy and safety confirm that it will be highly effective against Covid-19 and will have an immediate impact on this public health emergency," Pascal Soriot, Chief Executive Officer, said in a statement.

Analysis of data from a phase 3 trial of the vaccine developed by Oxford University showed that it was 90 percent effective at stopping the disease when half a dose was administered followed by a full dose. In another dosing regiment, when two full doses were administered, the vaccine was 62 percent effective, researchers said, resulting in combined average efficacy of 70 percent.

Click here for full story.