Update: influenza activity--worldwide and recommendations for influenza vaccine composition for the 1990-91 influenza season.
D000293:Adolescent; D000328:Adult; D000368:Aged; D000956:Antigens, Viral / Q000032:analysis; D001208:Asia / Q000453:epidemiology; D001315:Australia / Q000453:epidemiology; D004196:Disease Outbreaks / Q000517:prevention & control; D005060:Europe / Q000453:epidemiology; D006801:Humans; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control; D008875:Middle Aged; D009656:North America / Q000453:epidemiology; D009975:Orthomyxoviridae / Q000276:immunology
D000956:Antigens, Viral; D007252:Influenza Vaccines