More than 15.7 million doses of COVID-19 vaccines have been administered in the United States to date, according to data published on the Centers for Disease Control and Prevention's website.

Over 13.5 million people have received one or more doses of the vaccine, while more than 2 million have received two doses, according to the CDC data, which was updated Tuesday.

There were 168,058 new cases of COVID-19 confirmed in the United States on Tuesday, according to a real-time count kept by Johns Hopkins University.

The latest daily case count is far less than the country's all-time high of 298,031 newly confirmed infections on Jan. 2, Johns Hopkins data shows.

An additional 2,550 fatalities from COVID-19 were registered nationwide on Tuesday, down from a peak of 4,462 new deaths on Jan. 12, according to Johns Hopkins data.

COVID-19 data may be skewed due to possible lags in reporting over the holiday weekend and earlier holidays.

A total of 24,253,368 people in the U.S. have been diagnosed with COVID-19 since the pandemic began, and at least 401,730 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 nearing 300,000 on Jan. 2.

In a continued encouraging sign, the number of people currently hospitalized with COVID-19 in the United States decreased on 13 days in January, according to The COVID Tracking Project, a volunteer-run effort to track the U.S. outbreak.

That metric, which is "more resilient" than others to holiday reporting disruptions, increased six times this month, most recently on Jan. 12, The COVID Tracking Project said.

There are 123,820 people currently hospitalized with COVID-19 nationwide.

The U.S. also recorded 144,047 new cases of COVID-19 and 2,141 additional deaths from the disease on Tuesday, though national data was incomplete due to the holiday weekend, according to The COVID Tracking Project.

U.S. President-elect Joe Biden and Vice President-elect Kamala Harris honored the 400,000 Americans who have died from COVID-19 with a tribute in front of the Lincoln Memorial Reflecting Pool in Washington, D.C. on Tuesday evening.

The 400 lights along the pool were lit to symbolize the lives lost to the virus.

At the ceremony, part of the incoming administration's inaugural festivities, Harris called on Americans to "grieve and begin healing together."

"Though we may be physically separated, we, the American people, are united in spirit," she said.

Shortly after U.S. President Donald Trump announced his administration would be lifting COVID-19 travel restrictions for the United Kingdom, Brazil and much of Europe, President-elect Joe Biden's team said that would not be the case.

Biden's incoming White House press secretary, Jen Psaki, said the new administration doesn't intend to lift the travel restrictions next week.

"With the pandemic worsening, and more contagious variants emerging around the world, this is not the time to be lifting restrictions on international travel," Psaki wrote on Twitter late Monday. "On the advice of our medical team, the Administration does not intend to lift these restrictions on 1/26. In fact, we plan to strengthen public health measures around international travel in order to further mitigate the spread of COVID-19."

Trump issued a proclamation earlier Monday night, announcing he will rescind entry bans imposed because of the coronavirus pandemic on most non-U.S. citizens arriving from Brazil, the United Kingdom and much of Europe.

The travel restrictions were put in place last year toward the beginning of the pandemic, following calls from health officials who urged the president to stop the spread of the novel coronavirus.

The proclamation said the entry bans will be removed starting Jan. 26, the same day that all travelers must present a negative COVID-19 test or proof of recovery from the disease in order to enter the United States. Biden and his administration will be sworn in Wednesday.

"Public health officials in the jurisdictions have a proven record of working with the United States to share accurate and timely COVID-19 testing and trend data, and the United States has active collaborations with the jurisdictions regarding how to make travel safe between our respective countries," the proclamation states.

ABC News' Elizabeth Thomas contributed to this report.