Health Highlights: Dec. 23, 2020

Below are newsworthy items compiled by the HealthDay staff:

First COVID-19 Cases Reported in Antarctica

A COVID-19 outbreak in Antarctica means that the new coronavirus is now spreading on every continent.

Thirty-six people on a research base on Antarctica's northernmost Trinity Peninsula tested positive for COVID-19, the Chilean Army said Sunday. Until then, Antarctica had been the only continent that was free of the virus, CNN reported.

The affected personnel have been isolated and are being closely monitored, officials said.

COVID-19 was found in at least three people on a military vessel that had been supporting the base between late November and early December, CNN reported.

White House Pandemic Expert Dr. Deborah Birx Plans to Retire

White House coronavirus response coordinator Dr. Deborah Birx says she plans to retire, but didn't specify when that would happen.

In an interview Tuesday with the news site Newsy, Birx said she is willing to help President-elect Joe Biden's team with its coronavirus response, the Associated Press reported.

Birx recently became embroiled in controversy. A few days ago, the AP reported that she traveled out of state for Thanksgiving weekend to Delaware and was accompanied by family members -- even as the U.S. Centers for Disease Control and Prevention told Americans not to travel.

Birx said she went to winterize her property there, and that even though her family shared a meal while there, she "did not go to Delaware for the purpose of celebrating Thanksgiving," the AP reported.

U.S. Justice Department Sues Walmart Over Role in Opioid Crisis

Walmart is being sued by the U.S. Justice Department for its alleged role in the nation's opioid crisis.

A civil complaint filed Tuesday says Walmart unlawfully distributed controlled substances to its pharmacies at the height of the crisis, the Associated Press reported.

The company violated federal law by selling prescriptions for controlled substances that its pharmacists "knew were invalid," according to Jeffrey Clark, the acting assistant attorney general in charge of the Justice Department's civil division.

"Walmart knew that its distribution centers were using an inadequate system for detecting and reporting suspicious orders," Jason Dunn, the U.S. attorney in Colorado, claimed.

"As a result of this inadequate system, for years Walmart reported virtually no suspicious orders at all. In other words, Walmart's pharmacies ordered opioids in a way that went essentially unmonitored and unregulated," Dunn said.

Nearly two months ago, Walmart filed a lawsuit against the Justice Department and Drug Enforcement Administration. The company claims it's being blamed for the federal government's regulatory and enforcement failures in the opioid crisis, the AP reported.

In the lawsuit, Walmart wants a federal judge to rule that the federal government has no basis to seek civil damages.

Gators Forward Keyontae Johnson Leaves Hospital

Ten days after collapsing during a game, Florida Gators forward Keyontae Johnson was released from the hospital Tuesday, according to a family statement.

The 21-year-old collapsed on the court during a Dec. 12 game against the Florida Seminoles. After brief medical attention courtside, he was transported to a nearby hospital, CBS News reported.

"We continue to be amazed at the pace of his recovery and look forward to spending Christmas together as a family," the statement said.

The reason for Johnson's collapse isn't clear. He tested positive in the summer for COVID-19, which can cause an infection of the heart muscle, but players must undergo heart testing and physical exams before they can return to the court, CBS News reported.