Which statement about prevalence is true?

• A. It only counts new cases
• B. Is a measure of death rate
• C. It represents the total number of existing cases at a given time
• D. It is unaffected by duration of disease

Answer: (C)

Prevalence captures the burden of a disease by counting everyone who is currently living with it at a given time. It reflects the total number of existing cases, or the proportion of the population with the disease at that moment. This differs from incidence, which counts new cases that develop over a specific period. A statement that prevalence is a measure of death rate is incorrect because mortality tracks deaths from the disease, not how many people are currently diseased. The idea that prevalence is unaffected by the duration of disease is also incorrect: longer-lasting diseases keep people in the prevalence pool longer, increasing prevalence, while shorter durations reduce it as people recover or die. So the true description is that prevalence represents the total number of existing cases at a given time.