Starbucks is requiring its 220,000 workers to get the COVID-19 vaccine or be tested weekly, complying with the Biden administration's vaccine mandate for private businesses.

Employees must reveal their vaccination status by Jan. 10, according to a letter sent Monday by Starbucks Chief Operating Officer John Culver, Reuters first reported.

"This is an important step we can take to help more partners get vaccinated, limit the spread of COVID-19, and create choices that partners can own based on what's best for them," Culver wrote.

Workers will have until Feb. 9 to be fully vaccinated.

Those who choose to undergo weekly testing instead will be responsible for obtaining their own tests -- which cannot be self-administered or taken at home -- and submitting results.

The seven-day positivity rate at the U.S. Capitol COVID-19 testing center has increased from 1% to 13%, according to a letter sent from the Office of the Attending Physician to congressional offices on Monday.

Most cases have been breakthroughs among people who are fully vaccinated and have not “led to hospitalizations, serious complications, or deaths, attesting to the value of coronavirus vaccinations," the letter reads.

The letter also states that about 61% of COVID-19 infections at the Capitol have been linked to the omicron variant, and 38% are linked to the delta variant.

The OAP advised congressional offices to telework as much as possible and that "blue surgical masks, cloth face masks and gaiter masks must be replaced by the more protective KN95 or N95 masks."

New York City Mayor Eric Adams insisted that schools will stay open for in-person leaning despite the rapidly rising number of COVID cases.

“We’re really excited about the opening of our schools,” he said during a speech outside Concourse Village Elementary School in the Bronx on Monday. “We want to be extremely clear: the safest place for our children is a school building.”

As part of a plan to curb rates of infection, 1.5 million rapid at-home test kits are being being distributed to schools.

Students and adults who exhibit symptoms or have been exposed to a positive case will be required to have two negative tests over the course of five days before they can return to classes.

On Sunday, Adams told ABC's "This Week" that parents should "fear not sending [kids] back" to school after the winter break.

Meanwhile, several other school districts across the country, including Atlanta, Cleveland, Newark and Milwaukee, have opted for virtual learning for at least the first week of the new semester.

More than 100,000 Americans are currently hospitalized with COVID-19, according to data from the U.S. Department of Health and Human Services.

A total of 103,329 people are receiving medical care, which is an increase of 130% from the number recorded two months ago.

Of those patients, more than 17% -- about 18,000 -- are in intensive care units.

The newly updated figure is just shy of the hospitalization peak seen during the summer wave fueled by the delta variant, when 104,000 Americans were hospitalized with COVID in early September.

-ABC News' Arielle Mitropoulos

President Joe Biden announced Tuesday afternoon that he was doubling the federal government's purchases of Pfizer's COVID-19 antiviral pill, from 10 million to 20 million treatment courses.

"They’re a gamechanger and have the potential to dramatically alter the impact of COVID-19, the impact it's had on this country and our people,” Biden said.

He also warned that those who remain unvaccinated "will die" during the ongoing omicron surge.

“So there's no excuse, no excuse, for anyone being unvaccinated,” Biden said.

-ABC News' Ben Gittleson