Fig. 1.

Epidemic curve of confirmed pandemic (H1N1) 2009 cases in China, May 2009–21 March 2010. (1) 11 May 2009: first imported case; (2) 18 June 2009: first school outbreak; (3) 8 July 2009: adjustment of the measures for prevention and control. Close contacts: medical observation in the home; mild cases: isolation and treatment in the home; (4) 10 July–31 August 2009: school summer holidays; (5) 1–8 October 2009: National Day holidays; (6) 11–17 January 2010: influenza B virus became the predominant strain. (7) 14 February 2010: Chinese New Year.