Several hundred White House staffers have already been vaccinated against COVID-19 by the White House medical team, White House officials said, confirming a report from Axios.

The White House hopes to vaccinate all in-person staff in the next few weeks, officials said.

ABC News’ Molly Nagle contributed to this report

The United States is seeing improvements in COVID-19 infections and hospitalizations. In the last two weeks, the country's seven-day average of new COVID-19 cases has declined by 33.1%, according to ABC News' analysis of data compiled by The COVID Tracking Project, a volunteer-run effort to track the U.S. outbreak.

On Monday, Missouri reported the fewest number of new cases since September, while South Dakota reported the lowest number of new cases since July.

COVID-19 hospitalizations are also declining nationwide. The COVID Tracking Project said the number of people hospitalized with the disease in the U.S. is currently at its lowest since Dec. 14.

Hospitalizations are even trending down in California, which has more COVID-19 patients in hospitals than any other U.S. state.

ABC News’ Arielle Mitropoulous contributed to this report.

Colombian President Ivan Duque announced Tuesday that Defense Minister Carlos Holmes Trujilo died in the early morning hours from COVID-19 complications. He was 69.

"I can't express the pain that I have," Duque said in a statement while conveying his condolences to Trujilo's family.

Colombia has the third-highest number of confirmed COVID-19 cases in the Americas, behind the United States and Brazil, according to the World Health Organization.

ABC News’ Christine Theodorou contributed to this report.

Europe's longest land border, spanning more than 1,000 miles, has closed for the first time since World War II.

Sweden's temporary ban on entry from neighboring Norway went into effect Monday and will last until at least Feb. 14. The Swedish government has also extended an entry ban from the United Kingdom and Denmark until the same date.

The move comes amid concerns over a new, more contagious variant of the novel coronavirus that was first identified in the U.K. and has since spread to Norway's capital and the surrounding area.

On Saturday, shortly before Sweden announced the new travel ban, the Norwegian government imposed strict new lockdown measures for Oslo and nine neighboring municipalities due to an outbreak of the variant.

ABC News' Clark Bentson contributed to this report.

Dr. Anthony Fauci, chief medical adviser to U.S. President Joe Biden and the nation's leading infectious disease expert, said Americans can expect to see more COVID-19 vaccine doses available throughout the country in the coming weeks.

"As we get into February, March and April, we're going to see an escalation of availability of doses that we may have not had a week or two or three ago," Fauci, who is also the director of the National Institute of Allergy and Infectious Diseases, told ABC News chief anchor George Stephanopoulos Thursday on "Good Morning America."

Although COVID-19 data is starting to show some promising trends, Fauci said the U.S. outbreak is "still a very serious situation."

"If you look throughout the country, the dynamics of the outbreak are a little bit unstable," he noted, "even though for the most part we're seeing general trends, seven-day trends of cases going down and ultimately, hopefully, hospitalizations and deaths."

When asked about reopening schools safely, Fauci said COVID-19 transmission rates in schools actually appear to be less than in communities when the schools have the resources and protection they need.

"So if you have a situation where you have dynamics of a viral spread in a community, it's less likely that the children who are in the school -- if we do things right, it's less likely that they're going to get infected," he said. "Obviously we want to get the teachers vaccinated, we want to make sure they have the resources to do it correctly. But when you look at the history of how this virus is moving in schools, it seems to be less spreading there than it is in the community."

Fauci also expressed concern over the new, more contagious variant of the novel coronavirus that was first identified in South Africa and has since spread to dozens of other nations, including the United States.

"The one in South Africa, George, troubles me," he said, explaining that lab experiments show the neutralizing antibodies induced by existing COVID-19 vaccines are "diminished by multifold" when tested against the South Africa variant, called B1351.

"It's still within the range of what you would predict to be protective," he added, "but I take no great comfort in that."

However, scientists are already working on vaccines that will specifically target the South Africa strain, according to Fauci.

"May not be necessary," he said, "but if it is we'll already be on the road to be able to give people a boost that directs against the South African isolate."