The effect of vaccine on a closed epidemic of Hong Kong influenza.
D000293:Adolescent; D000328:Adult; D001741:Black or African American; D044383:Black People; D001991:Bronchitis / Q000517:prevention & control; D002986:Clinical Trials as Topic; D004196:Disease Outbreaks; D006723:Hong Kong; D006801:Humans; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009787:Occupational Medicine; D010919:Placebos; D013019:South Africa; D014611:Vaccination
D007252:Influenza Vaccines; D010919:Placebos