Anthony Fauci: 'We have got to double down' to fight Covid

Dr Anthony Fauci, the top US infectious diseases expert, says the country needs to "double down" on public health measures such as mask-wearing and social distancing.

Speaking to Chatham House on Thursday, he warned that the cold weather makes for a "challenging and ominous situation".

His comments come as the US is seeing a surge in coronavirus cases, with more than 100,000 new cases per day for the past week.