Americans brace for Covid 'surge upon a surge'

America should prepare for a "surge upon a surge" in coronavirus cases as millions of travelers return home after the Thanksgiving holiday, top US scientist Anthony Fauci warned Sunday. ​​The United States is the world's worst-affected country, with 266,831 Covid-19 deaths, and President Donald Trump's administration has issued conflicting messages on mask-wearing, travel and the danger posed by the virus.