Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Attack rate
Introduction
An attack rate in epidemiology is the incidence of infection in a group of people over a period of time, usually in relation to foodborne illness.
It is defined as the number of exposed persons infected with the disease divided by the total number of exposed persons.
This ratio is measured from the beginning of an outbreak to the end of the outbreak.