Effectiveness of influenza vaccination in the elderly in South Africa.
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D013019:South Africa / Q000453:epidemiology; D014611:Vaccination
D007252:Influenza Vaccines