What is the prevention paradox?

• A. Many people must participate to achieve a large population-level benefit, yet individuals may gain little.
• B. Prevention benefits are evenly distributed to all individuals.
• C. Prevention yields large benefits to most individuals.
• D. Prevention is always cost-effective.

Answer: (A)

The prevention paradox is about how a prevention measure can produce a large benefit for a whole population only if a lot of people actually use it, even though the benefit to any given person is small. In other words, widespread participation drives big population-level effects, but an individual’s personal risk reduction—or felt benefit—tends to be modest. That’s why the correct statement describes that many people must participate to achieve a large population-level benefit, yet individuals may gain little.

In contrast, benefits aren’t typically evenly distributed, so some people may see more personal benefit than others. It’s also not true that prevention always yields large benefits for most individuals, or that prevention is always cost-effective; cost-effectiveness depends on costs, the size of the effect, and how many people participate.