From the Centers for Disease Control. Influenza activity--worldwide, 1990-91.
D000293:Adolescent; D000368:Aged; D002648:Child; D014943:Global Health; D006801:Humans; D009980:Influenza A virus; D009981:Influenza B virus; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000453:epidemiology*; D014481:United States / Q000453:epidemiology
D007252:Influenza Vaccines