Influenza update: influenza B virus now predominates in England and Wales.
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D002648:Child; D002675:Child, Preschool; D004739:England / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D009981:Influenza B virus / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology; D008875:Middle Aged; D014852:Wales / Q000453:epidemiology