title: The measurement by serological means of the impact of the Hong Kong/68 influenza virus on a population.
mesh_terms: D000293:Adolescent; D000328:Adult; D001938:Brazil; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007251:Influenza, Human / Q000453:epidemiology*; D008297:Male; D009975:Orthomyxoviridae / Q000276:immunology