Health officials in a Colorado county reported a second local case of a coronavirus variant from the United Kingdom -- one that experts have said maybe especially contagious.

And this a day after the first known case of the variant in the US was announced in Elbert County.First reported US case of the highly-infectious Covid-19 variant that emerged in the UK has been confirmed in the state of Colorado. The patient, a man in his 20s with no recent travel history, is currently in isolation.

State health officials said they were working to identify contacts and other potential cases of the new variant.

US President-elect Joe Biden criticised the Trump administration's distribution of vaccines. He said the programme was falling behind schedule. The US has recorded more than 19 million infections and more than 337,000 deaths from coronavirus, the highest figures in the world.

Experts say that new variant is considerably more transmissible than previous strains but not necessarily any more dangerous for those infected.