50 years of influenza surveillance: much still to do to stop a common killer.
D003153:Community Health Services / Q000458:organization & administration*; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control; D011159:Population Surveillance; D016019:Survival Analysis; D014944:World Health Organization