Coronavirus tests are giving people positive results even when they had the virus 70 days ago, an Oxford University academic has warned, amid fears they are too sensitive. Prof Carl Heneghan, director of the Centre for Evidence-Based Medicine, said eight days after contracting Covid-19, the chances the infected person will pass the virus on "goes down to zero" if they have no symptoms. However, he said fragments of the virus can still remain in the body for many weeks afterwards - with some studies showing intermittent shedding up to 70 days later - leading to a positive test and skewing...