The failure by the US to bring Covid-19 cases under control is scrambling business expectations of a rapid economic revival, forcing companies to reset plans and revise forecasts as they also grapple with a new federal vaccine mandate. Revenues have fallen at a quarter of US small businesses in each of the past three weeks while just 8 per cent saw revenue growth, according to an Economic Innovation Group study. A growing minority now expects a full economic recovery to take more than six months.