Donald Trump will spend a “few days” at a military hospital after contracting Covid-19, the White House said on Friday, a move set to fuel concerns that his condition is more serious than previously thought. At 6.20pm on a day of turbulence even by the standards of the Trump White House, the US president departed by helicopter for Walter Reed national military medical center. Wearing a face mask and suit and walking normally, Trump gave reporters a thumbs-up and a short wave but did not stop to talk. He saluted a marine officer and patted a rail with his right hand on the walkway up to Marine One. He was followed by his chief of staff, Mark Meadows, and other staff – sharing the confined space of the helicopter despite Trump’s infection. Ten minutes later, the president disembarked at the grounds of Walter Reed, saluted and climbed into a vehicle. Even as Trump was travelling, a video was posted to his Twitter account in which the president made his first public remarks since testing positive. Standing before a fireplace in a suit, white shirt and blue tie, the president addressed the camera directly, saying: “I want to thank everybody for the tremendous support. I’m going to Walter Reed hospital. I think I’m doing very well but we’re going to make sure that things work out.“The first lady is doing very well. So thank you very much, I appreciate it, I will never forget, thank you.”It was the most dramatic hospitalisation of a US president since Ronald Reagan survived a would-be assassin’s bullet outside a Washington hotel in 1981. Officials insisted it was a precautionary step and that Trump would work from the hospital’s presidential suite, which is equipped to allow him to continue his official duties. Alyssa Farah, the administration’s communications director, sought to calm fears over Trump’s condition, tweeted that he “is in good spirts, has mild symptoms, and has been working throughout the day”. But she added: “Out of an abundance of caution, and at the recommendation of his physician and medical experts, he will be working from the presidential offices at Walter Reed for the next few days.”Sean Conley, his physician, said in a letter that Trump has been given the experimental antibody drug Regeneron, and he has been taking zinc, vitamin D, an antacid, melatonin and a daily aspirin. Conley said Trump is “fatigued but remains in good spirits”, and is being “evaluated by a team of experts”. Media reports suggested that Trump has a low-grade fever. Conley added that the first lady, Melania Trump, who also tested positive, “remains well” with “only a mild cough and headache”. The rest of the Trump family has tested negative. But critics demanded greater transparency and suggested that the administration’s record offers cause for scepticism. In 2018, doctor Ronny Jackson claimed that Trump has “great genes” and, with a healthier diet, “might live to be 200 years old”.