US President-elect Joe Biden has announced he would surge federal resources into making "thousands" of vaccine sites, while also deploying mobile clinics and expanding the public health workforce to accelerate the rollout of Covid-19 shots.
Mr Biden has said he wants 100 million people in the US to receive injections during his first 100 days in office, a drastic increase from the current pace.
Five days until he is inaugurated, Mr Biden said: "This is going to be one of the most challenging operational efforts ever undertaken by our country.
"But you have my word: we will manage the hell out of this operation."
On Thursday, he announced a $1.9 trillion stimulus package for the US economy that included $20 billion for vaccines and $50bn for testing.
Official data shows some 30 million doses had been sent to states with only 11.1 million injected into arms, well below the Trump administration's target of 20 million in December.
Mr Biden's plan would drastically increase the role of the federal government in the distribution effort, mobilising the Federal Emergency Management Administration and reimbursing states that deploy their National Guard.
The president-elect has also asked Congress to fund the expansion of the nation's public health workforce to 100,000 personnel, nearly triple the current number.
More than 388,000 people in the US have lost their lives to the virus, a figure that is likely to have crossed 400,000 by the time Mr Biden is sworn into office on Wednesday.
The outlook looks likely to worsen as the B.1.1.7 variant of the coronavirus establishes itself in the US as the dominant strain in March, according to modelling by the Centres for Disease Control and Prevention.
The CDC said the strain, which first emerged in Britain where it drove a near exponential rise in cases, could further stretch American hospitals and increase the percentage of people who need to be vaccinated to achieve herd immunity.
The incoming Biden administration also said it would invoke the Defence Production Act to boost vaccine supply, pay special attention to ethnic minority communities disproportionately affected by the pandemic, and embark on an education campaign to build vaccine confidence.
Mr Biden has also announced that he is upgrading the White House science advisor position to cabinet-level - a sharp break from predecessor Donald Trump.
Eric Lander, a geneticist who helped map the human genome, will head the White House Office of Science and Technology Policy (OSTP) and advise Mr Biden.
"Science will always be at the forefront of my administration - and these world-renowned scientists will ensure everything we do is grounded in science, facts, and the truth," he said in a statement announcing the appointment of Mr Lander and other experts.
"Their trusted guidance will be essential as we come together to end this pandemic, bring our economy back, and pursue new breakthroughs to improve the quality of life of all Americans," he added.
Mr Lander is president and founding director of the Broad Institute of MIT and Harvard, a top non-profit biomedical research.
He tweeted that he was "humbled and excited" to serve, adding: "So much to be done, and it will take everyone working together."
Mr Trump is famously sceptical of science, questioning climate change and once referring to Anthony Fauci and other government pandemic advisers who called on Americans to wear masks and social distance as "idiots".