The weekly reported new cases of confirmed H1N1 infection in different geographic regions of mainland China during May 7 th to August 12 th , 2009 are presented in Figure 2 . A total of 26 provinces or cities had confirmed cases of infection, among which Beijing city had the highest number of infection (670 cases), followed by Guangdong province(628 cases), Shanghai city(318 cases), Zhejiang province (214 cases), and Fujian province(195 cases).