Outbreak Attack Rates: By Exposure, Overall and Secondary
Outbreak attack rates as CDC's Principles of Epidemiology defines them.
Open the tool → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Exposures, one per line
- Potato salad, 30, 99, 5, 100 Ham, 10, 50, 10, 50
Result: Potato salad: 30.3% of those exposed (30 of 99) and 5.0% of those not exposed (5 of 100); risk ratio 6.06 (95% CI 2.45 to 14.98).
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Exposures, one per line: name, ill exposed, total exposed, optionally ill unexposed, total unexposed
- Total ill
- Total persons at risk
- Household or contact group members
- Primary cases
- Secondary cases among contacts
How this is calculated
Citation
CDC. Principles of Epidemiology in Public Health Practice, 3rd ed. Lesson 3, Measures of Risk: section 2 (attack rate, food-specific and secondary attack rates) and section 5 (risk ratio). Risk ratio interval: Deeks JJ, Higgins JPT, Statistical algorithms in Review Manager (Cochrane, May 2022). Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.