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.

The chief science adviser to Operation Warp Speed, the U.S. government's initiative to expedite vaccine development, said he doesn't know what vaccine-related executive order President Donald Trump is expected to sign on Tuesday.

"Frankly, I don't know and, frankly, I'm staying out of this. I can't comment," Dr. Moncef Slaoui told ABC News chief anchor George Stephanopoulos in an interview Tuesday on "Good Morning America."

When pressed on the matter, Slaoui added: "Our work is, you know, rolling. We have plans. We feel that we can deliver the vaccines as needed, so I don't exactly [know] what this order is about."

Trump is expected to discuss the order at a COVID-19 vaccine summit to be held at the White House later Tuesday, multiple White House officials told reporters during a background briefing on Monday evening. While it's not entirely clear on how exactly the order would work, the move is designed to prevent the U.S. government from shipping any vaccine doses it has purchased to aid foreign countries until all the needs within the United States are met.

White House officials also denied reports that the Trump administration turned down an offer last summer to purchase an additional 400 million doses of a COVID-19 vaccine developed by U.S. pharmaceutical giant Pfizer and its German partner BioNTech, and that the companies now may not be able to provide more of their vaccine to the United States until June 2021 because they have committed those doses to other countries.

When asked about the matter, Slaoui explained Operation Warp Speed's strategy in securing vaccine doses.

"We selected six different vaccines to build a portfolio to manage the risk that some may work and some may not work, but also to ensure that as more than one would work that we would accumulate vaccine doses from this portfolio of vaccines," he said. "If somebody came to us and said, let's buy more of this vaccine or that vaccine, no one reasonably would buy more from any one of those vaccines because we didn't know which one would work and which one may be better than the other. Once the vaccine's performance becomes known is the right time, given the strategy we've taken, to go and order more vaccine doses, which we may be doing. And frankly, the constructive thing to do if one of the suppliers has challenges producing enough vaccine doses is to roll our sleeves and help ensure that capacity can be increased."

Slaoui said he's confident the U.S. government will be getting vaccines to Americans who need them "as soon as possible" and that plans are "still on track."

"We will work with Pfizer to try and increase capacity and have those vaccines available," he said. "We have two more vaccines from J&J and AstraZeneca that will be completing their Phase 3 trials in January and most likely, I hope, be approved for use in February. We have tens of millions of doses from those vaccines, you know, participating to the volume of vaccines we need to immunize the U.S. population as we promised, all of it by the middle of the year 2021 and that's still on track."

Slaoui said Operation Warp Speed has a meeting with President-elect Joe Biden's transition team scheduled for Thursday.

"We look forward to, you know, sharing all the information and working together," he said. "Our objective has always been outside of politics and making sure we make available these vaccines for the U.S. people, and that's what we're doing."

ABC News' Ben Gittleson, John Parkinson and Eric Strauss contributed to this report.