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Definition of prevalence


Updated October 09, 2012


Prevalence is the number of people living with a particular disease during a specified period of time.

Whereas incidence describes the number of new cases of a disease diagnosed during a particular time, prevalence includes all cases of that disease, both new and existing, in a particular population.

The incidence (number of new cases per year) of lung cancer is higher than breast cancer, but the prevalence is lower, since the survival rate for lung cancer is lower.

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