Update: Influenza Activity - United States and Worldwide, May 20-September 22, 2012

MMWR Morb Mortal Wkly Rep. 2012 Oct 5;61(39):785-9.


During May 20-September 22, 2012, the United States experienced low levels of seasonal influenza activity overall; however, more seasonal influenza viruses were detected than in the summer months of previous years. Influenza A (H1N1)pdm09 (pH1N1), influenza A (H3N2), and influenza B viruses were detected worldwide and were identified sporadically in the United States. In July, influenza A (H3N2) variant viruses (H3N2v) were first detected in Indiana, and since July 12, a total of 306 cases have been reported from 10 states. This report summarizes influenza activity in the United States and worldwide since May 20, 2012.

MeSH terms

  • Adolescent
  • Aged
  • Child
  • Child, Preschool
  • Drug Resistance, Viral
  • Female
  • Global Health
  • Humans
  • Infant
  • Influenza A Virus, H1N1 Subtype* / genetics
  • Influenza A Virus, H1N1 Subtype* / isolation & purification
  • Influenza A Virus, H3N2 Subtype* / genetics
  • Influenza A Virus, H3N2 Subtype* / isolation & purification
  • Influenza, Human / epidemiology*
  • Male
  • Population Surveillance*
  • Seasons
  • United States / epidemiology