President-elect Joe Biden on Tuesday outlined his top three COVID-19 priorities for his first 100 days in office: a 100-day mask-wearing program, 100 million doses of the vaccine into Americans arms in the first 100 days, and getting schools reopened permanently.

"We didn’t get into this mess quickly. We're not going to get out of it quickly," Biden said. "But I'm absolutely convinced that, in 100 days, we can change the course of the disease and change life in America for the better."

Biden warned that distributing the vaccine would be one of the hardest and costliest challenges the country will face and will require the cooperation of Congress.

“We’re gonna need Congress to fully fund vaccine distribution to all corners of the country, to everyone," Biden said. "I'm encouraged by the bipartisan efforts in Congress around a $900 billion economic relief package which I've said is critical, but this package is only a start for more action early next year."

"We'll also need the Trump administration to act now," Biden added, "to purchase the doses it has negotiated with Pfizer and Moderna, and to work swiftly to scale manufacturing to U.S. populations and the world."

ABC News' Molly Nagle contributed to this report.

Washington Gov. Jay Inslee said the state's restriction on social gatherings, restaurants, bars, gyms and religious services will be extended to Jan. 4, 2021.

"We need to buckle down through the holidays," Inslee tweeted.

"The hospitalization projections are scary. We’re already at 80% ICU capacity," Inslee said, adding, "our hospitals are still on the brink."

Washington state has over 184,000 diagnosed COVID-19 cases and at least 2,941 fatalities.

Thirty-five juveniles and 116 adults were arrested at a "super spreader" underground party this weekend in Palmdale, California, said Los Angeles County Sheriff Alex Villanueva.

The sheriff said the party was in clear violation of the governor's stay-at-home order, adding that the party would have been targeted without the pandemic due to allegations of drugs, weapons, prostitution and underage trafficking.

ABC News' Alex Stone contributed to this report.

Massachusetts will roll back its reopening plans on Sunday as cases and hospitalizations rise in the aftermath of Thanksgiving, Gov. Charlie Baker said.

Capacity will be reduced from 50% to 40% in facilities including offices, gyms, places of worship and retail stores, Baker said.

In offices, people must wear masks when they're not alone, and at gyms, customers must wear masks at all times.

Changes are also coming to Massachusetts restaurants. Customers must wear masks at all times except when eating and drinking, and their time at tables will be capped at 90 minutes.

U.S. Surgeon General Jerome Adams urged people to take the coronavirus pandemic seriously and follow public health guidelines as infections and hospitalizations soar across the country.

"I want the American people to know this virus is incredibly unforgiving, cases are going up, hospitalizations are going up, my colleagues are dog-tired and we need you to hang on just a little bit longer because we've got vaccines coming but we want as many people to be alive to get them as possible and a lot of that is going to depend on your behavior," Adams told ABC News chief anchor George Stephanopoulos in an interview Monday on "Good Morning America."

Although "more people than ever are wearing masks," Adams said he's "very" concerned by the number of people who still "don't understand how much spread is occurring by people who don't have symptoms."

About 20 million "full doses" of COVID-19 vaccines will be available by the end of the year, according to Adams, who urged every American to be immunized against the virus as soon as a vaccine is authorized and made available.

"It's a way that we can ultimately end this pandemic, but it doesn't matter if people won't get the vaccination," the surgeon general said. "We know that vaccine levels are only about 50% for adults for flu and they go down to about 40% for African-Americans."

Adams said he is working with historically black colleges and universities as well as faith communities to bolster vaccine confidence among all populations. The White House is also hosting a vaccine summit Tuesday, he said.

"One thing you can all do right now, it's national flu immunization week, get your flu shot because half a million people were hospitalized last year with the flu," Adams said. "We simply can't afford for that to happen this year with hospitals being overwhelmed."

The surgeon general said the current surge in infections across the country "is different than earlier surges," because it's not about a lack of masks or personal protective equipment, nor is it due to a lack of testing.

"It's really about health care capacity, and certain places are just being overwhelmed," he said. "So we know that we can actually help them with their health care capacity by immunizing their health care staff. We're going to leave it up to the states, but we're going to give them guidance."

Adams noted it's also important to vaccinate those who are most likely to die from COVID-19.

"We know that 40 to 50% of the deaths are occurring in people who are in longterm care facilities who are older," he said.