President Donald Trump's physician has said he is no longer at risk of transmitting the coronavirus - but did not say explicitly whether Trump had tested negative for it. In a memo released on Saturday night, White House physician Dr. Sean Conley said Trump met the CDC criteria for safely discontinuing isolation and that by 'currently recognized standards' he was no longer considered a transmission risk.The diagnosis came as the president prepared to resume campaign rallies and other activities. The memo did not declare Trump had tested negative for the virus. But sensitive lab tests - like the PCR test - detect virus in swab samples taken from the nose and throat, and can detected even a minuscule viral load. Share this article Share Dr. William Morice, who oversees laboratories at the Mayo Clinic, said earlier this week that using the PCR tests, the president´s medical team could hypothetically measure and track the amount of virus in samples over time and watch the viral load go down.Some medical experts had been skeptical that Trump could be declared free of the risk of transmitting the virus so early in the course of his illness. Just 10 days since an initial diagnosis of infection, there was no way to know for certain that someone was no longer contagious, they said.The memo followed Trump´s first public appearance since returning to the White House after being treated for the coronavirus. Hundreds of people gathered Saturday afternoon on the South Lawn for a Trump address on his support for law enforcement from a White House balcony.Trump took off a mask moments after he emerged on the balcony to address the crowd on the lawn below, his first step back onto the public stage with just more than three weeks to go until Election Day. He flouted, once more, the safety recommendations of his own government just days after acknowledging that he was on the brink of 'bad things' from the virus and claiming that his bout with the illness brought him a better understanding of it.His return was a brief one. With bandages visible on his hands, likely from an intravenous injection, Trump spoke for 18 minutes, far less than at his normal hour-plus rallies. He appeared healthy, if perhaps a little hoarse, as he delivered what was, for all intents and purposes, a short version of his campaign speech despite the executive mansion setting. Though billed as an official event, Trump offered no policy proposals and instead delivered the usual attacks on Democrat Joe Biden while praising law enforcement to a crowd of several hundred, most of whom wore masks while few adhered to social distancing guidelines.'I´m feeling great,' said Trump, who said he was thankful for their g