XIAN, CHINA - NOVEMBER 9:  Medical workers inject A/H1N1 flu vaccines for kindergarten teachers 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. Getty Images logo Getty Images 27 months ago

XIAN, CHINA - NOVEMBER 9: Medical workers inject A/H1N1 flu vaccines for kindergarten teachers 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.