As Canada deals with its largest measles outbreak in more than a decade, health experts say a COVID-era tool could help tame the spread.

Wastewater surveillance, which involves testing sewage samples for viral pathogens, became essential during the pandemic. The data helped overwhelmed health officials map out COVID-19's path and better predict the trajectory of cases. 

At the time, it was praised as a critical public health tool that could serve as a warning system to keep Canadians safe from fu…