Positivity Rate vs. Prevalence

The positivity rate—also referred to as “percent positive rate” or “percent positive” is the percentage of all coronavirus tests performed that are actually positive. Positivity rate is usually expressed as a percentage. It is an indicator of whether enough testing is occurring if enough asymptomatic and mild cases are being tested.

Prevalence, on the other hand, is a specific number of people who have (or had) COVID-19 during a specific time period. This would be the number of truly positive individuals out of the entire population—not just those who is tested. Prevalence can help researchers and decision-makers understand the larger picture of COVID-19 spread in a specific area or population.

SOURCES: Johns Hopkins Bloomberg School of Public HealthNIH