PHOTO DAVID BOILY, ARCHIVES LA PRESSE (Washington, D.C.) Nearly a quarter of people who have contracted COVID-19 face, a month later or more, health problems they had not experienced before their infection, according to a large study that analyzed the medical data of nearly two million Americans affected by the virus. The survey is the largest ever conducted to study the long-term effects of the disease, according to Fair Health, an independent organization that has collected information provided by health insurance companies. Data from some 1.960 million people diagnosed positive for COVID-19 between February and December 2020 were reviewed. "While many patients recover from COVID-19 within a few weeks, some develop persistent or new symptoms more than four weeks after being diagnosed," the study says. The two main problems experienced were pain (neuralgia, muscle pain...) for 5% of people, and difficulty breathing, in 3.5% of cases. They were followed by...