Covid-19 wastewater surveillance is promising tool, but critical challenges remain

Covid-19 surveillance is at a crossroads in the United States. With at-home tests now outnumbering those done in laboratories, official case counts are more incomplete than ever as the nation -- and world -- faces down increasingly transmissible coronavirus variants. Wastewater surveillance is poised to fill in the gaps and help avoid the threats that an invisible wave of the virus could bring. This surveillance can help identify trends in transmission a week or two earlier than clinical testing, giving public health leaders the chance to focus messaging and resources. It can be used as a tool to sequence the virus and find new variants sooner, too. But eagerness to use this tool is stifled by uncertainty about exactly how to do so, along with a lack of resources and support to learn. Testing sewage for virus particles can provide early warning signs of increased transmission in a community, capturing even those who have asymptomatic infections or aren't being tested.