A medical worker helps a student put on a facial mask in this file photo. Liao Yuxue, an official with the Shenzhen Center for Disease Control (CDC) and Prevention, has warned students about flu and diarrhea caused by Norovirus and hand-foot-and-mouth diseases after the new term started, as it will be the high season for such diseases from now until March. The plan to provide free flu vaccinations for primary and middle school students after the new term starts in fall has been approved by the authority, according to the CDC. Xinhua