XIAN, CHINA - NOVEMBER 9: A medical worker injects an A/H1N1 flu vaccine for a student in a middle school on November 9, 2009 in Xian of Shaanxi Province, China. China's State Council said on October 28 that the country faces 'severe challenges' in the prevention and control of A/H1N1 flu, following a student from Beijing University of Aeronautics and Astronautics died of the virus, the fourth victim in Chinese mainland. A nationwide H1N1 flu vaccination campaign has been started in many regions across the country.