Update: Influenza activity--United States, 2001-02 season.
Although influenza activity in the United States remained low from October through mid-January, the number and percentage of specimens testing positive for influenza viruses have increased in recent weeks. Laboratory-confirmed influenza infections have been reported from 45 states. The predominant influenza viruses isolated this season have been type A (H3N2) viruses that are well matched by this season's influenza vaccine. This report summarizes U.S. influenza activity from September 30, 2001 through January 19, 2002 and updates the previous summary.
D006801:Humans; D009980:Influenza A virus; D009981:Influenza B virus; D007251:Influenza, Human / Q000453:epidemiology*; D012621:Seasons; D014481:United States / Q000453:epidemiology