A record 325,000 children tested positive for COVID-19 last week amid the nation's most significant COVID-19 infection surge yet, according to the American Academy of Pediatrics and the Children’s Hospital Association.

Children accounted for about 17.4% of last week's reported COVID-19 cases, down from previous weeks, when children accounted for more than a quarter of all new cases.

A total of nearly 7.9 million children have tested positive for the virus, since the onset of the pandemic.

ABC News' Arielle Mitropoulos

New York's hospitals will be required to report a breakdown of how many COVID-19 patients were admitted due to the coronavirus and how many were admitted for other needs and only discovered they were infected during their stays.

During a COVID-19 briefing on Monday, Gov. Kathy Hochul cited anecdotal reports of as many as 50% of patients at some hospitals testing positive for the virus who were actually admitted for other reasons, such as car accidents.

"I just want to always be honest with New Yorkers about how bad this is," Hochul said. "Yes, the sheer number of people infected are high, but I want to see whether or not the hospitalizations correlate with that."

She continued, "And I'm anticipating to see that at least a certain percentage overall are not being treated for COVID."

Hospitals will begin reporting their breakdowns Tuesday, but it's unclear how soon the data will be publicly available.

-ABC News' Joshua Hoyos and Will McDuffie

U.S. Surgeon General Dr. Vivek Murthy warned that COVID-19 cases and hospitalizations will continue to increase as the omicron variant rapidly spreads across the country.

"The next few weeks are going to be tough for us," he told ABC's "The View" on Monday. "We’re already seeing record levels of cases, and we're seeing hospitalizations starting to tick up. We're seeing some of our hospital systems getting strained at this point."

Information from South Africa and the United Kingdom indicates omicron could be less severe than previous COVID-19 variants, Murthy said.

"We’re still going to see a lot of people get sick and a lot of hospitalizations, but the overall severity may end up being significantly lower," he said.

Murthy said both South Africa and the U.K. "had a very rapid rise, but then they had a very steep fall" in cases

"I'm hoping that that’s what happens here too," he added.

-ABC News' Joanne Rosa

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.

COVID-19 vaccines can cause temporary changes to menstrual cycles, a new study from Oregon Health and Science University suggests.

Researchers looked at nearly 4,000 women who use Natural Cycles, a Food and Drug Administration-approved birth control app.

They found that some women who received COVID-19 vaccines experienced changes, with the most common being periods starting late by about one day.

However, the effects were temporary with a normal menstrual cycle returning within one or two months after getting the shot.

The team emphasized the findings do not mean COVID-19 vaccines have an impact on current or future fertility.

-ABC News' Katie Kindelan