After a slowdown in reporting and testing over the Thanksgiving holiday, week-over-week data shows dramatic increases in new cases and new deaths in the U.S., according to an internal memo from the United States Department of Health and Human Services that was obtained by ABC News.

From Dec. 1 to Dec. 7, the country recorded 1,341,309 new cases, which was an 18.8% jump from the previous seven-day period, according to the memo.

During that same period, the U.S. saw 15,202 new coronavirus related deaths, which was a 50.6% increase compared with the previous week, HHS said.

About 29% of the nation's hospitals have more than 80% of their ICU beds filled, the memo said.

-ABC News' Josh Margolin

The Trump administration declined additional doses of the Pfizer coronavirus vaccine late this summer when the pharmaceutical company offered them to the U.S. government, a senior Trump administration official familiar with the matter confirmed to ABC News.

Pfizer may be unable to produce more of the vaccine for United States citizens until June 2021 because it has committed those doses to other countries.

"The U.S. government placed an initial order of 100 million doses for Pfizer-BioNTech’s COVID-19 vaccine, and Pfizer is ready to begin shipping initial doses soon after receiving an Emergency Use Authorization from the FDA," Pfizer told ABC News in a statement.

"Any additional doses beyond the 100 million are subject to a separate and mutually-acceptable agreement. The company is not able to comment on any confidential discussions that may be taking place with the U.S. government."

The development was first reported by New York Times.

-ABC News' Josh Margolin and Eric Strauss contributed to this report.

On Friday, hospitals in Massachusetts will stop offering elective surgeries that can be safely postponed, Gov. Charlie Baker said at a press conference Monday afternoon.

"This action will free up unnecessary staffing and beds," Baker said. "We all know we're in the midst of a second surge. We're seeing a higher number of new cases each day. And in turn, an increase in hospitalizations statewide."

On Sunday, Massachusetts reported 4,747 new infections and a seven-day average testing positivity rate of 5.3%. There are 1,416 people currently hospitalized with COVID-19.

Despite the worsening statistics, the state is better prepared this time around, Baker insisted. In addition to reallocating hospitals resources, the state is ramping up and winterizing testing sites, stockpiling PPE and preparing two field hospitals in Worcester and Lowell.

-ABC News' Kelsey Walsh contributed to this report.

Navajo Nation begins a three-week emergency lockdown on Monday, during which residents are required to remain at home 24 hours a day, seven days a week.

Essential businesses, including grocery stores, gas stations, laundromats, hay vendors and restaurants providing drive-thru or curbside service, may remain open on weekdays between 7 a.m. and 7 p.m. Off-reservation travel is not permitted and on weekends, a full lockdown will be in place.

"The Navajo Nation’s health care system is in a state of major crisis," Myron Lizer, vice president of Navajo Nation, said in a statement. "We cannot be careless and we have to stay the course."

The rules include exceptions for essential workers and emergency situations. Residents are permitted to leave their homes for essential food, medicine and supplies, as well as outside exercise within the vicinity of their homes and wood gathering.

The lockdown rules will be in effect until Dec. 28.

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.