Dr Ron Daniels is one of Britain’s leading intensive care doctors. A consultant at University Hospitals Birmingham NHS Foundation Trust he was on the frontline when Britain’s Covid-19 epidemic first peaked and, with colleagues, saved many lives. Like many doctors, Dr Daniels himself came down with the virus. He suffered only a mild bought of the disease but even now, several months later, he can feel its impact. “The cough has gone but I’m I'm still a bit breathless,” he says. “For example, I routinely go up five or six flights of stairs at the hospital instead of taking the lift and I'm more breathless now than I normally would be. It's not stopping me doing anything. It’s just noticeable”. With the initial Covid emergency now ebbing in several countries, doctors and scientists are turning their attention to the longer-term health impacts of Covid-19. The virus was only discovered six months ago and the evidence remains thin but it is already clear that doctors and health systems will be dealing with the fallout for decades to come. How long can symptoms last, mental and physical? The majority of people which catch Covid-19 suffer only very mild disease and it passes like a common cold or sore throat, causing no lasting damage. But for those, like Dr Daniels, who are harder hit but for whom the disease remains relatively mild, breathlessness, fatigue and muscle ache can last for some considerable time. Early on in the crisis, researchers at King’s College London developed a Covid-19 app for people to record their symptoms daily. They report that one in ten people have symptoms lasting for between eight to 10 weeks and say symptoms can fade away only to come bouncing back. Perhaps as many as 30,000 in the UK have experienced this form of the disease, informally dubbed “long-term Covid”. Professor Paul Garner, an expert in global health at the Liverpool School of Tropical Medicine, suffered weeks of exhaustion after contacting what he suspects was Covid-19. “Sometimes I felt better and became optimistic,” he wrote in the British Medical Journal, “but then the next day I felt as though someone had hit me around the head with a cricket bat.” Are there mental health impacts? The World Health Organisation (WHO) says the psychological impact of Covid-19 to date is best seen in “elevated rates of stress or anxiety”. “But as new measures and impacts are introduced – especially quarantine and its effects on many people’s usual activities, routines or livelihoods – levels of loneliness, depression, harmful alcohol and drug use, and self-harm or suicidal behaviour are also expected to rise”. Again, even the most experienced are effected. “The virus disappears, but its consequences linger for weeks”, reported the virologist Prof Peter Piot, director of the London School of Hygiene & Tropical Medicine, who fell ill with COVID-19 in mid-March and whose diary of his own illness has done much to raise awareness of the virus’s long term effects. Prof Poit, who has devoted much of his life to fighting viruses including HIV and Ebola, was hospitalised and remained breathless many weeks later. But the virus also impacted his psyche. “Now that I have felt the compelling presence of a virus in my body myself, I look at viruses differently. I realise this one will change my life, despite the confrontational experiences I’ve had with viruses before. I feel more vulnerable,” he writes. What about those with severe disease? The more severe the disease, the stronger its impact, and for those who require mechanical ventilation to survive, Covid-19 is likely to be with them the rest of their lives. Doctors report a wide array of complications in such patients ranging from permanent scarring of the lungs, to kidney, heart and even brain damage. Many suffer septic shock. In others, the virus prompts an immune response which makes the blood more viscous and likely to clot. This can lead to heart attack and stroke. To assess the likely long term impact in these cases, doctors have turned to studies of patients who were hit by Severe acute respiratory syndrome (Sars) in 2003 and others hit with Acute Respiratory Distress Syndrome (ARDS). A Hong Kong study of SARS survivors showed one in two had much poorer exercise capacity and health status after two years. Only 78% of were able to return to full‐time work 1 year after infection. Another study revealed that 40% of people recovering from SARS still had chronic fatigue symptoms 3.5 years after being diagnosed. The biggest study of ARDS survivors shows a similar pattern. It tracked 109 survivors of ARDS over 5 years after discharge from intensive care. “Exercise limitation, physical and psychological sequelae, decreased physical quality of life, and increased costs and use of health care services are important legacies of severe lung injury,” it concluded. Precise estimates for the long term health impacts of Covid-19 will not be known for many years to come but that they will be significant there can be little doubt. As Prof Poit puts it: “Many people think COVID-19 kills one per cent of patients, and the rest get away with some flulike symptoms. But the story gets more complicated…. there will be hundreds of thousands of people worldwide, possibly more, who will need treatments such as renal dialysis for the rest of their lives. The more we learn about the coronavirus, the more questions arise. We are learning while we are sailing”.