Figure. . Number of estimated influenza cases and filled prescriptions for influenza antiviral drugs during pandemic (H1N1) 2009 in the United States, September 2009–March 2010. The estimates of cases for April–August 2009 are not available on a weekly basis. During April 12–July 23, 2009, there were 3.1 million cases and 1.3 million prescriptions filled for influenza antiviral drugs. For the month of August 2009, there were 1.6 million cases and 354,000 prescriptions filled for influenza antiviral drugs. Estimates of cases from Shrestha et al. (1); number of prescriptions filled from the IMS Health Xponent database (3).