York Region stands to lose reliability in its warning signs for population-wide COVID-19 and influenza cases as provincial wastewater surveillance ends, public health said.

The Ontario government announced it is ending the program, which allowed public health units to track COVID-19 in wastewater sampling sites across the province, on July 31.

York Region associate medical officer of health Dr. Sarah Erdman said the tool was very useful to help inform public health decisions.

“Given tighter testing eligibility for COVID-19 and influenza, wastewater surveillance provided helpful information about the burden of disease and community transmission among the general population,” Erdman said. “It also provided an early warning of surges ahead of an increase in cases and hospitalizations; without wastewater data, York Region will be unable to reliably obtain these estimates moving forward.”