Wastewater Data for Measles

What can wastewater data for measles tell us?

Wastewater data are updated every Friday with the previous week’s data, which allows for data to be reviewed for accuracy. Data may change as more reports are received.

Measles detection category definitions:

Measles Detection: Any of the samples at a site were positive for measles virus during the week reported
No Detection: Measles virus was not detected in any of the samples at a site during the week reported
No Data: A site has not reported measles testing data for the week shown, but has reported measles testing data at least once in the past 8 reporting weeks

Measles detections in wastewater in the past week

This interactive map shows current site-level data for detections of measles virus in wastewater. Each dot on the map represents a wastewater sampling site. Click on a state to zoom in.

Measles detection in wastewater in the past six weeks

This searchable table shows site-level data for detections of measles virus in wastewater for the past six weeks. The date in the column header is the last day for that week of sample collection. The table shows if:

+ Measles was detected at the site

– Measles was not detected at a site

No Data No measles virus testing data was reported

To filter for sites with a recent measles detection, type + in the search bar. Scroll right to see more dates.

About Wastewater Monitoring: Wastewater monitoring detects viruses that can spread from one person to another within a community. It detects viruses from infected people, even if they do not have symptoms. Wastewater monitoring can detect viruses earlier than clinical testing and, in some cases, before sick people go to their healthcare provider or hospital. Wastewater monitoring can complement other data for measles. Learn more about wastewater monitoring at CDC’s Wastewater Program.

Data Display: For measles, CDC displays data from wastewater that was tested for the type of virus that spreads between people and can cause outbreaks, also called “wild-type measles virus.” A detection of wild-type measles virus in wastewater means that people who currently have or recently had measles may be present in the community. This could include people who live or work in the community, or those who traveled through the community. It is still possible for there to be measles infections present in a community despite no wastewater detection.

Measles Risk: The overall measles outbreak risk to the general population is low. However, measles cases are increasing globally, increasing the chance of importations into the United States and subsequent risk of outbreaks, particularly in communities with low vaccination rates. Learn more about measles.

Public health response to detections: When measles virus is detected in wastewater, CDC works with state and local health departments to identify whether any people in the area have developed measles symptoms or have been recently diagnosed with measles. Together, CDC and health departments decide next steps, such as whether to alert local healthcare providers of potential cases, increase public outreach and education, conduct vaccination clinics, or take additional measures, as appropriate.

Learn more about:

CDC’s wastewater surveillance data sources: About CDC’s National Wastewater Surveillance System
Public Data Display Policies: About Wastewater Data

Data for the prior six weeks are displayed, which cover several incubation periods for measles virus and align with data display timeframes on other CDC webpages.

A site is classified as having a detection when wastewater concentrations for measles exceed the laboratory’s specific limit of detection. Each laboratory calculates this limit based on its unique methodology.

For sites where multiple samples are collected, or multiple laboratories test samples from the same site in a given week, if any sample tests positive for the measles virus, the site is classified as having a detection.

Additional wastewater data are available at CDC Wastewater Data for Measles.