Confirming Measles Outbreaks By Wastewater Testing in 2024

Throughout January 2024, twenty-three measles cases have been detected in various United States cities, as the Centers for Disease Control and Prevention (CDC) reported last week.

In Philadelphia's outbreak, public health leaders used multiple tactics to identify nine measles cases.

Since the City of Philadelphia is already participating in a U.S. CDC poliovirus surveillance program, they could have leveraged that innovative system to identify measles virus hot spots.

In September 2020, the CDC launched the National Wastewater Surveillance System to coordinate the nation's capacity to track the presence of viruses in wastewater samples collected across the country.

Measles wastewater surveillance relies on tests to find genetic evidence of DNA or RNA. When people are infected, their stools include pathogens that show up in sewage systems.

According to previous research studies, wastewater testing can identify the measles virus.

In September 2023, researchers concluded multiplex analysis using wastewater provides a fast and cost-effective way to monitor viral diseases in a population or environment.

In 2017, researchers detected measles virus RNA in wastewater where measles cases were identified.

The practical question was raised by an article written by Cassandra Willyardarchive in MIT Technical Review on January 26, 2024 .... about whether detecting measles in wastewater would have any public health value.

Cases tend to get noticed because measles is rarely asymptomatic, and the rash is distinctive.

"I actually think you could make the argument that measles is even more important to [detect] than covid or influenza or any of the other pathogens that we're looking for," says Samuel Scarpino, an epidemiologist at Northeastern University in Boston, MA.

With nearly 80% of U.S. households already connected to municipal wastewater collection systems, wastewater testing for measles is a logical use-case.

On November 30, 2022, the CDC announced it was expanding wastewater testing.

Dr. José R. Romero, Director of CDC.'s National Center for Immunization and Respiratory Diseases, indicated that poliovirus wastewater testing would continue into 2024 in cities like New York. 

Because the U.S. has a very high measles vaccination rate, most cases are related to international travelers. This indicates airports and airplane wastewater systems are prime targets to integrate into the U.S. wastewater testing network.