A medical worker collects a swab sample from a girl at a community in Qiaoxi District of Shijiazhuang, capital of north China's Hebei Province, Jan. 6, 2021. Chinese cities are tightening control measures to tackle the resurgence of the novel coronavirus through the winter months following recent sporadic spikes in confirmed cases. Anti-epidemic workers stand fast at their positions regardless of the heavy wind and cold weather to support those in need. (Xinhua/Mu Yu)