Epidemic (Epi) Curves for Coronavirus COVID-19
Updated: Wednesday, August 18, 2021 14:06 ET
On this site
On this page
Cases and Deaths for Selected Countries
Projected Deaths from COVID-19 in the U.S.
Global Epidemic Curve for COVID-19
What is an Epidemic (Epi) Curve?
- An epidemic curve, also known as an epi curve or epidemiological curve, is a statistical chart used to visualize the onset and progression of a disease outbreak.
- Epi curves typically display a graph of the onset of illness among cases in an outbreak.
- Horizontal x-axis shows the date of illness onset among cases.
- Vertical y-axis shows the number of cases.
- For the COVID-19 outbreak, major agencies display cases differently:
Flattening the COVID-19 Epidemic Curve
- Without speedy and coordinated public health actions such as rapid testing, isolation of cases, "social distancing" and stay-at -home policies, the number of COVID-19 cases could rise beyond the capacity of the healthcare system to handle severe cases (see red curve in relation to healthcare system capacity line in figure above). This occurred in Wuhan, China and is happening now in parts of Italy.
- The goal is to "flatten" the curve (green curve above) – reduce the daily rate of new cases so that the number of severe cases can be handled effectively by the healthcare system.
- Note that public health actions taken to "flatten the curve" do not guarantee the reduction in total number of cases during a pandemic. That will be determined by additional factors such the speed by which other effective prevention measures (e.g., vaccines) are developed.
- Interactive tutorial on epidemic curves – from the CDC
Share this Page
- Total confirmed cases of COVID-19. Our World in Data. [https://ourworldindata.org/grapher/covid-confirmed-cases-since-100th-case]
- Coronavirus Disease 2019 (COVID-19) in the U.S. United States Centers for Disease Control and Prevention. [https://www.cdc.gov/coronavirus/2019-ncov/cases-in-us.html]
- COVID-19 Forecasts. U.S. Centers for Disease Control and Prevention. [https://www.cdc.gov/coronavirus/2019-ncov/covid-data/forecasting-us.html]
- United States COVID-19 Hospital Needs and Death Projections. Institute for Health Metrics and Evaluation (IHME), University of Washington, Seattle. 2020. [https://covid19.healthdata.org/projections]
- Coronavirus Disease 2019 (COVID-19) Situation Reports. World Health Organization. [https://www.who.int/emergencies/diseases/novel-coronavirus-2019/situation-...]
- Interpretation of Epidemic (Epi) Curves during Ongoing Outbreak Investigations. US Centers for Disease Control and Prevention. [https://www.cdc.gov/foodsafety/outbreaks/investigating-outbreaks/epi-curve...]
- Qualls N, Levitt A, Kanade N, et al. Community Mitigation Guidelines to Prevent Pandemic Influenza - United States, 2017. MMWR Recomm Rep. 2017;66(1):1-34. [PMID:28426646]
- Coronavirus Locations: COVID-19 Map by County and State. USAFacts.org. [https://usafacts.org/visualizations/coronavirus-covid-19-spread-map/]
- Key Metrics for COVID Suppression. Harvard Global Health Institute. [https://globalepidemics.org/key-metrics-for-covid-suppression/]
- Nationwide COVID-19 Metrics Since April 1. The COVID Tracking Project. [https://covidtracking.com/data/charts/us-all-key-metrics]
- Quick-Learn Lesson: Create an Epi Curve. US Centers for Disease Control and Prevention. [https://www.cdc.gov/training/quicklearns/createepi/]