The Parliament of Ghana will reduce its sessions to twice a week after dozens of lawmakers and legislative staff tested positive for COVID-19.

Addressing lawmakers on the floor Thursday, Speaker of Parliament Alban Bagbin said at least 15 members of Parliament and 56 staffers have tested positive for COVID-19 so far. They have been asked to self-isolate while steps are being taken to have members of their household tested as well.

There are still 48 members of Parliament who have yet to be tested, according to Bagbin.

Starting next week, Ghana's Parliament will only sit on Tuesdays and Thursdays in an effort to control the spread of the virus. Only the lawmakers and staffers who are needed on those days will be allowed inside the building, Bagbin said.

Schools reopened across the West African nation in January, following a 10-month closure due to the coronavirus pandemic. But as COVID-19 infections rise again, Ghanaian President Nana Akufo-Addo on Sunday reimposed a ban on social gatherings.

Ghana has confirmed at least 63,883 cases of COVID-19 since the start of the pandemic, including 390 deaths, according to the latest data from the Africa Centers for Disease Control and Prevention.

The Allegheny County Health Department in Pennsylvania said 750 residents made appointments to be vaccinated against COVID-19 on Thursday through a new phone registration offered by the United Way of Southwestern Pennsylvania's 211 helpline.

The call center began receiving calls well before the official start time at noon on Thursday. In the first five minutes following the announcement of the phone registration, there were 653 calls into the helpline. More than 15,000 calls were coming in per second throughout the day, attempting to reach the center, according to a press release from the Allegheny County Health Department.

"We have known for a while that the demand for vaccines far outweighs the supply, and today’s phone registration only underscores that," Dr. Debra Bogen, director of the Allegheny County Health Department, said in a statement Thursday. "While we realize that there were many, many people who were frustrated because they did not receive an appointment, we also were able to serve 750 individuals who may not have had the opportunity to schedule otherwise."

The 211 helpline is for only scheduling vaccination appointments for Allegheny County residents who are 65 and older. Appointments are for the Allegheny County Health Department's Point of Dispensing inside the DoubleTree by Hilton Hotel in Monroevile, about 10 miles east of Pittsburgh. Other vaccine providers in the county have separate registration systems, the health department said.

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.

Cases of the more contagious U.K. variant of the COVID-19 virus is spreading rapidly through the U.S., as much as doubling every 10 days, a new study suggests.

The study has not peer reviewed, so it has not been scrutinized for inaccuracies or context by specialists.

It is still not known whether the U.K. variant is more virulent or deadly, but it is more transmissible. The Centers for Disease Control and Prevention warned last month that the U.K. variant could become predominant in the U.S. by March if spread the way it did in the U.K.

Vaccines don’t seem to be strongly impacted by the U.K. variant, but scientists are concerned about the efficacy of the vaccines against the South African variant.

-ABC News’ Eric Strauss