A staggering 5,078 fatalities from COVID-19 were registered in the United States on Thursday, marking a new single-day record, according to a real-time count kept by Johns Hopkins University.

It's the first time since the start of the coronavirus pandemic that the U.S. has recorded more than 5,000 deaths from the disease in a single day. Thursday's tally far exceeds the country's previous all-time high of 4,466 new deaths registered on Jan. 12, Johns Hopkins data shows.

There were also 122,473 new cases of COVID-19 confirmed nationwide on Thursday, down from a peak of 300,282 newly confirmed infections on Jan. 2, according to Johns Hopkins data.

COVID-19 data may be skewed due to possible lags in reporting over the Martin Luther King Jr. Day holiday weekend last month as well as during storm-related closures in some northeastern states earlier this week.

A total of 26,679,554 people in the U.S. have been diagnosed with COVID-19 since the pandemic began and at least 455,869 have died, according to Johns Hopkins data. The cases include people from all 50 U.S. states, Washington, D.C., and other U.S. territories as well as repatriated citizens.

Much of the country was under lockdown by the end of March as the first wave of pandemic hit. By May 20, all U.S. states had begun lifting stay-at-home orders and other restrictions put in place to curb the spread of the novel coronavirus. The day-to-day increase in the country's cases then hovered around 20,000 for a couple of weeks before shooting back up over the summer.

The numbers lingered around 40,000 to 50,000 from mid-August through early October before surging again to record levels, crossing 100,000 for the first time on Nov. 4, then reaching 200,000 on Nov. 27 before topping 300,000 on Jan. 2.

So far, the U.S. Food and Drug Administration has authorized two COVID-19 vaccines for emergency use -- one developed by U.S. pharmaceutical giant Pfizer and its German partner BioNTech, and another developed by American biotechnology company Moderna and the National Institute of Allergy and Infectious Diseases. More than 35 million vaccine doses have been administered nationwide, according to the latest data from the Centers for Disease Control and Prevention.

Pharmaceutical giant Johnson & Johnson has submitted its application for emergency use authorization of its COVID-19 vaccine to the U.S. Food and Drug Administration, the company announced Thursday evening.

The single-shot vaccine is 66% effective at preventing symptomatic COVID-19, 85% effective at preventing severe illness and 100% protective from hospitalization and deaths, according to Johnson & Johnson.

Johnson & Johnson said it expects to have product available to ship immediately following authorization and to supply 100 million doses to the United States in the first half of 2021.

"Today’s submission for emergency use authorization of our investigational single-shot COVID-19 vaccine is a pivotal step toward reducing the burden of disease for people globally and putting an end to the pandemic," Dr. Paul Stoffels, vice chairman of the executive committee and chief scientific officer at Johnson & Johnson, said in a statement Thursday, adding that the company is "working with great urgency to make our investigational vaccine available to the public as quickly as possible."

The FDA said it will meet on Feb. 26 to review Johnson & Johnson's COVID-19 vaccine. An emergency-use authorization could be issued any time after the meeting concludes.

In addition to potentially offering a convenient, single-dose vaccine against the novel coronavirus, the Johnson & Johnson shot doesn't need to be frozen for shipping and long-term storage, like the COVID-19 vaccines developed by Pfizer and Moderna.

ABC News' Sony Salzman contributed to this report.

Beginning Feb. 15, anyone coming to the United Kingdom from a country on its travel ban list of COVID-19 hotspots must quarantine in a government-approved hotel for 10 nights, the U.K. government announced Thursday.

Most foreign nationals from high-risk nations already face U.K. travel restrictions due to the coronavirus pandemic. But this new rule will apply to U.K. citizens and residents arriving from one of the 33 "red list" countries: Angola, Argentina, Bolivia, Botswana, Brazil, Burundi, Cape Verde, Chile, Colombia, Democratic Republic of the Congo, Ecuador, Eswatini, French Guiana, Guyana, Lesotho, Malawi, Mauritius, Mozambique, Namibia, Panama, Paraguay, Peru, Portugal (including Madeira and the Azores), Rwanda, Seychelles, South Africa, Suriname, Tanzania, United Arab Emirates, Uruguay, Venezuela, Zambia and Zimbabwe.

Security will escort guests to their quarantine rooms when they arrive and must accompany them if they wish to access outside space for fresh air or a smoke. Three meals per day and laundry service will also be provided during their stay.

Those in quarantine will be required to take a COVID-19 test on both Day 2 and Day 8.

ABC News’ Zoe Magee contributed to this report.

Denmark, the Netherlands and Norway have joined the growing list of European countries that have said they won't recommend older age groups receive the COVID-19 vaccine developed by England's University of Oxford and British-Swedish pharmaceutical giant AstraZeneca until more data from clinical trials becomes available.

The Danish Health Authority said Thursday that it will recommend the Oxford/AstraZeneca vaccine to people under the age of 65 who are not at risk of serious illness from COVID-19. The drugs regulator citied a lack of documentation as to the vaccine's efficacy in older age groups.

The Norwegian Institute of Public Health said it will also limit use of the Oxford/AstraZeneca vaccine to those under 65 because there had been few participants older than that in the trial conducted by AstraZeneca.

Meanwhile, the Dutch Health Council said the efficacy of the Oxford/AstraZeneca vaccine in those over 55 "cannot yet be calculated because they participated only to a limited extent in the vaccine studies."

Belgium, France and Germany have made similar moves recently, while Switzerland went a step further and declined to authorize the Oxford/AstraZeneca vaccine for any age group, citing insufficient data.

An accommodation facility for refugees in the German city of Cologne has been hit by new, more contagious variants of the novel coronavirus, city officials said.

At least 41 residents of the Herkulesstrasse facility have tested positive for COVID-19. Variants first identified in South Africa or Brazil have been detected in 31 of them so far, according to a statement from the city government on Sunday.

At least 16 staff members at the facility have also tested positive for COVID-19, with the South Africa variant detected in 11 of them so far. Variant analysis is still pending on the other five, according to the statement.

All residents of the facility have been under quarantine since Friday, while the site has been under surveillance since Sunday. Entry into the refugee accommodation center, which can house up to 600 people, is currently banned, according to the statement.

The first known COVID-19 cases were confirmed among two employees at the facility about 10 days ago, while the first case of a variant was confirmed last week, according to the statement.

Dr. Harald Rau, head of Cologne's public health department, said the detection of variants at the refugee accommodation center "is a clear alarm signal for all of us."

"I ask all people in Cologne to avoid contact even more consistently than before and to follow the distance and hygiene rules of infection protection," Rau said in a statement Sunday.