China health authorities told WHO that known pathogens are causing respiratory diseases in children, with an earlier-than-usual uptick due to Covid curbs being lifted. Reports of undiagnosed pneumonia in children's hospitals sparked concerns of a novel virus. Mycoplasma is the main culprit, causing mild colds in adults but pneumonia in younger kids. NHC is boosting local clinics to ease pressure on hospitals, while resistance to antibiotics is high.