Immunization against influenza.
D002648:Child; D005060:Europe; D006801:Humans; D007109:Immunity; D007114:Immunization; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D009656:North America; D013020:South America
D007252:Influenza Vaccines