Joe Biden has warned “people may die” if his incoming presidential administration continues to be impeded by Donald Trump.
Speaking in Delaware, the president-elect said co-ordination was needed to tackle the coronavirus outbreak.
He called President Trump’s refusal to acknowledge he lost the vote, despite calls to do so from both sides, “totally irresponsible”.
The Trump campaign launched a flurry of legal challenges in the wake of the 3 November vote to contest ballot counts.
The General Services Administration (GSA), the government agency tasked with beginning the transition process for a new president, has yet to recognise Mr Biden and his running mate Kamala Harris as winners, leaving them without access to sensitive government briefings that are normally provided to an incoming administration.
Aides to the Democratic president-elect have said that Mr Trump’s refusal to engage in a transition also means Mr Biden’s team has been excluded from planning around a vaccination distribution strategy.
Calling nationwide vaccine distribution a “huge undertaking”, Mr Biden said that if his team had to wait until 20 January – his presidential inauguration – until they could begin work on the distribution programme, they would be behind by “over a month and a half”.