A growing number of China's doctors and nurses are catching COVID-19 and some have been asked to keep working, as people showing mostly moderate symptoms throng hospitals and clinics, according to medical staff and dozens of posts on social media. China's health authority did not immediately respond to a request for comment on infections among medical staff. Health experts say China's sudden loosening of strict COVID rules is likely to trigger a surge in severe cases in coming months, and hospitals in big cities are already showing signs of strain. Reuters was unable to immediately get verification from hospitals on...