Update: influenza activity - United States, 2011-12 season and composition of the 2012-13 influenza vaccine.
During the 2011-12 influenza season in the United States, influenza activity* occurred at low levels during October through December and increased in January and February before peaking in mid-March. Influenza A (H3N2) viruses predominated overall, but influenza A (H1N1)pdm09 (pH1N1) and influenza B viruses also circulated widely. This influenza season was mild compared with recent years, with a lower percentage of outpatient visits for influenza-like illness (ILI),† lower rates of hospitalizations, and fewer deaths attributed to pneumonia and influenza. This report summarizes influenza activity in the United States during the 2011-12 influenza season (October 2, 2011-May 19, 2012) and reports the recommendations for the components of the 2012-13 Northern Hemisphere influenza vaccine.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000956:Antigens, Viral / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D024882:Drug Resistance, Viral; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D053122:Influenza A Virus, H3N2 Subtype / Q000302:isolation & purification*; D009981:Influenza B virus / Q000302:isolation & purification*; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000401:mortality* / Q000517:prevention & control*; D008875:Middle Aged; D010045:Outpatients; D011159:Population Surveillance; D012621:Seasons; D014481:United States / Q000453:epidemiology; D055815:Young Adult
D000956:Antigens, Viral; D007252:Influenza Vaccines