US Democratic presidential candidate Joe Biden has bluntly contradicted President Donald Trump's suggestion that a coronavirus vaccine may be only weeks away, warning Americans they cannot trust the president's word. "The idea that there's going to be a vaccine and everything's gonna be fine tomorrow - it's just not rational, not reasonable," Mr Biden said during a CNN town hall in Moosic, Pennsylvania.
Mr Trump again said on Wednesday that a vaccine for Covid-19, the disease caused by the virus, could be ready for distribution ahead of the election on 3 November.
Most health experts, including Robert Redfield, the director of the Centers for Disease Control and Prevention, have said a vaccine will not be widely available until mid-2021.