The U.S. government is buying 600,000 more doses of sotrovimab, the only the monoclonal antibody treatment expected to hold up against omicron, according to the drug makers, GlaxoSmithKline and Vir Biotechnology.

These doses are set to be delivered to the government over the next two months, the drug makers said.

This brings total sotrovimab doses purchased by the federal government to approximately 1 million.

Short supply of sotrovimab has been a growing concern for the White House as omicron spreads.

Until recently the government had not invested in buying bulk stock of sotrovimab, as it has with other monoclonal treatments. The government spent billions buying Regeneron and Eli Lilly's products to ensure there would be enough supply, but both of those may not hold up against omicron.

-ABC News' Sasha Pezenik

Florida reported 126,704 new COVID-19 cases this weekend, ABC Miami affiliate WPLG reported, citing CDC data.

Orlando opened a new testing site Monday at Camping World Stadium.

About 3,000 United Airlines workers currently have COVID-19, though none are in the hospital, the airline said.

On one recent day, one-third of all United Airlines employees at Newark Airport called in sick, the airline said.

United CEO Scott Kirby said the airline is cutting its near-term flight schedule to ensure they have enough staffing.

Kirby added that, prior to the vaccine requirement, United had one employee die each week from COVID-19.

-ABC News' Sam Sweeney

Some 20 million people across three Chinese cities are now under lockdown due to COVID-19 outbreaks.

Anyang, home to 5.5 million people, was the latest city to lock down its residents after discovering two cases of the fast-spreading omicron variant. Another 13 million people are under lock down in Xi'ian and 1.1 million in Yuzhou, with both cities still battling the highly contagious delta variant. Neither has reported any cases of omicron.

Meanwhile, restrictions have been imposed in the port city of Tianjin, about 80 miles southeast of Beijing, which is to host the 2022 Winter Olympics next month. The city's 14 million people are being tested for COVID-19 after two locally transmitted cases of omicron were detected over the weekend -- the first for mainland China.

-ABC News' Karson Yiu

The labs shouldering much of the nation's PCR COVID-19 testing are getting slammed with demand again during omicron's surge, and now they're grappling with a new challenge: their workforces are getting hit by the virus they've been tasked with tracking.

The American Clinical Laboratory Association, the national trade association representing some of the leading clinical labs responsible for COVID diagnostics, is warning that their members' workforce is strained as more workers call out sick.

"Labs are now facing a wave of new issues brought on by a fast-spreading variant that has not spared the laboratory care work force," an ACLA spokesperson told ABC News.

COVID-19 infections have increased laboratory staff sick leave -- a "significant factor in determining overall capacity" at an industry-wide level, the spokesperson said.

"We have been pressured to get our capacity where we believe it can be because of the labor problems we see," Quest Diagnostics CEO Steve Rusckowski said Wednesday at the JPM Healthcare Conference. "Some of this is just getting the labor to do our work, but secondly, is because of callouts because of the virus have been considerable over the last two weeks."

-ABC News' Sasha Pezenik