• December was the deadliest month for America during the pandemic. Yet President Donald Trump barely uttered a word about Covid-19's tragic toll.
• Instead, the president spent the month obsessing over unfounded claims of a stolen election and lashing out at members of his own party.
• And, on Thursday, the last day of the month and the year, Trump tweeted a video in which he boasted about his administration's response to the pandemic.

WASHINGTON — In the final days of 2020, the United States saw coronavirus deaths spike, cases surge to staggering levels, hospitals strained and the rollout of desperately needed vaccines fall short of expectations.

December was the deadliest month for America during the pandemic. Yet President Donald Trump barely uttered a word about Covid-19's tragic toll.

Instead, the president spent the month obsessing over unfounded claims of a stolen election, delaying relief legislation before signing it, weighing in on cable news broadcasts and lashing out at members of his own party.

And, on Thursday, the last day of the month and the year, Trump tweeted a video in which he boasted about his administration's response to the pandemic.

During December, the country plunged into what would become its toughest battle against Covid-19, even as vaccines started to go out. The nation reported more than 6.1 million new infections and more than 74,140 deaths, according to data compiled by Johns Hopkins University.

The latest totals make December the deadliest month of the Covid-19 pandemic in the United States, surpassing April, when more than 60,738 Americans lost their lives to the coronavirus.

Since the start of the coronavirus outbreak, at least 342,414 Americans have died because of the disease, which Trump has repeatedly pledged on 40 different occasions would go away.

In a recorded message released Thursday, Trump took the lion's share of the credit for the unprecedented speed in the development of vaccines calling the feat a "medical miracle."

"Thanks to Operation Warp Speed we developed a vaccine in just nine months, we've already begun a nationwide vaccination program, and we're sending the vaccine all over the world. The world will benefit we'll benefit, and everybody's calling to thank me," the president said.

Trump also took a moment to praise his work on the economy, saying that his administration "built the greatest economy in the history of the world."

"We're doing numbers now like nobody's ever seen before, including having the highest stock market in the history of the world," Trump said, adding "the best is yet to come" in his signoff.

The White House did not immediately respond to a request for comment.

Tweets and golfing

Trump, who spent the past week vacationing at his private club in Palm Beach, Florida, returned to the White House on Thursday as lawmakers debated legislation that would increase Covid relief payments to $2,000 amid historic unemployment and business closures.

The president himself pushed for these higher payments, although the Republican leader in the Senate, Mitch McConnell, has resisted holding a stand-alone vote on the bill providing for the higher payments, which passed with bipartisan support in the House.

While in Palm Beach, Trump spent several days golfing at his for-profit golf course and sent 110 tweets which were largely focused on false claims of a rigged presidential election and the upcoming Senate runoff votes in Georgia.

Trump, despite a slew of failed legal challenges, has not conceded the election to Democrat Joe Biden, who will be inaugurated Jan. 20. The president also took to Twitter to garner support for an upcoming rally in Georgia.

The president's refusal to address other aspects of the unfolding public health disaster comes as the governors of Colorado and California confirm a new and potentially more infectious strain of Covid-19 in their states.

Hospital struggles and vaccine stumbles

Officials from the Centers for Disease Control and Prevention said Wednesday that the new strain could add pressure to the nation's hospitals, which are already overwhelmed with Covid-19 patients.

Staff-strapped hospitals from coast to coast are already running out of available intensive care units and standard beds for the surge in patients, data published by the Department of Health and Human Services shows.

Earlier this month, the United States began to roll out vaccines to combat the disease. But health officials have warned that a vaccine won't give the country immediate relief from the outbreak.

The nation's health officials have previously said their goal is to vaccinate at least 20 million Americans with their first shots before the end of the year. They are set to fall well short of that goal.

Read more: Trump blames states as he faces criticism for slow Covid vaccine rollout

More than 11.4 million doses of Pfizer's and Moderna's two-dose vaccines have been distributed across the country as of Monday morning. Approximately 2.1 million of those shots have been administered to people, according to the CDC.

Trump, facing criticism for the missed vaccination goal, blamed the disorganized rollout of the vaccines on states.

"The Federal Government has distributed the vaccines to the states," the president said in a tweet. "Now it is up to the states to administer. Get moving!"

-- CNBC's Kevin Breuninger, Will Feuer and Noah Higgins-Dunn contributed to this report.