Influenza.
D000328:Adult; D000368:Aged; D000914:Antibodies, Viral; D000956:Antigens, Viral; D004196:Disease Outbreaks / Q000453:epidemiology*; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology*; D009975:Orthomyxoviridae / Q000276:immunology
D000914:Antibodies, Viral; D000956:Antigens, Viral