Medical workers wait to board a train to Shanghai at Nanchang Railway Station in Nanchang, east China's Jiangxi Province, April 3, 2022. A team of medical workers left Jiangxi Province Sunday for Shanghai to help aid the COVID-19 control efforts there. (Xinhua/Peng Zhaozhi)

Medical workers are seen before setting out for Shanghai at Nanchang Railway Station in Nanchang, east China's Jiangxi Province, April 3, 2022. A team of medical workers left Jiangxi Province Sunday for Shanghai to help aid the COVID-19 control efforts there. (Xinhua/Peng Zhaozhi)

Medical workers from Shandong Province take part in a departure ceremony before leaving for Shanghai, in Jinan, east China's Shandong Province, April 3, 2022. A team of some 1,100 medical workers left Jinan Sunday for Shanghai to help fight COVID-19 on the front lines. (Xinhua/Xu Suhui)

Medical workers board a train to Shanghai at Nanchang Railway Station in Nanchang, east China's Jiangxi Province, April 3, 2022. A team of medical workers left Jiangxi Province Sunday for Shanghai to help aid the COVID-19 control efforts there. (Xinhua/Peng Zhaozhi)

Medical workers board a train to Shanghai at Nanchang Railway Station in Nanchang, east China's Jiangxi Province, April 3, 2022. A team of medical workers left Jiangxi Province Sunday for Shanghai to help aid the COVID-19 control efforts there. (Xinhua/Peng Zhaozhi)

Medical workers pose for a photo before setting out for Shanghai at Nanchang Railway Station in Nanchang, east China's Jiangxi Province, April 3, 2022. A team of medical workers left Jiangxi Province Sunday for Shanghai to help aid the COVID-19 control efforts there. (Xinhua/Peng Zhaozhi)

Medical workers from Shandong Province take part in a departure ceremony before leaving for Shanghai, in Jinan, east China's Shandong Province, April 3, 2022. A team of some 1,100 medical workers left Jinan Sunday for Shanghai to help fight COVID-19 on the front lines. (Xinhua/Xu Suhui)

Medical workers from Shandong Province take part in a departure ceremony before leaving for Shanghai, in Jinan, east China's Shandong Province, April 3, 2022. A team of some 1,100 medical workers left Jinan Sunday for Shanghai to help fight COVID-19 on the front lines. (Xinhua/Xu Suhui)

Medical workers from Shandong Province take part in a departure ceremony before leaving for Shanghai, in Jinan, east China's Shandong Province, April 3, 2022. A team of some 1,100 medical workers left Jinan Sunday for Shanghai to help fight COVID-19 on the front lines. (Xinhua/Xu Suhui)

Medical workers from Shandong Province take part in a departure ceremony before leaving for Shanghai, in Jinan, east China's Shandong Province, April 3, 2022. A team of some 1,100 medical workers left Jinan Sunday for Shanghai to help fight COVID-19 on the front lines. (Xinhua/Xu Suhui)