Figure 1. . Confirmed cases of influenza A(H1N1)pdm09 virus infection, People’s Republic of China, 2009. A) Number and proportion of confirmed A(H1N1)pdm09 cases by type (international travel–related cases, nonoutbreak cases, outbreak cases). B) Age distribution of patients with confirmed cases of A(H1N1)pdm09 infection gathered from different data sets. C, D) Number of confirmed A(H1N1)pdm09 cases by date of illness onset during May–August 2009 (C) and May–November 2009 (D) from case-based surveillance and outbreak investigations.