Update: Influenza Activity--United States, October 3--December11, 2010.

The article discusses influenza activity in the U.S. from October 3 to December 11, 2010. A total of 2,807 respiratory specimens were found to be positive for influenza viruses. Most of the cases have been reported from Region 4, the region where influenza B viruses have been reported more frequently. During the 2010-2011 season, the Centers for Disease Control and Prevention (CDC) has antigenically characterized 89 influenza viruses collected by laboratories. For 6.9% of all deaths reported to the Cities Mortality Reporting System, pneumonia and influenza was blamed as an underlying cause of death.