Enter the number of people who contracted a disease after a specific event and the total number of people expose to the event to determine the attack rate.

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## Attack Rate Formula

The following formula is used to calculate an attack rate.

A = #NC / #PE

- Where A is the attack rate
- #NC is the number of cases of a disease in people exposed to a specific event
- #PE is the number of people exposed to the specific event

## Attack Rate Definition

An attack rate is defined as the ratio of people that because sick after being exposed to a disease to the number of people exposed.

## Attack Rate Example

How to calculate an attack rate?

**First, determine the number of cases of a disease in people exposed.**Calculate the number of people that contracted the disease.

**Next, determine the number of people exposed.**Measure the total number of people exposed.

**Finally, calculate the attack rate.**Calculate the attack rate using the equation above.

## FAQ

**What is attack rate?**

Attack rate is a medical term used to describe the proportion of people who became sick after being exposed to a specific event.