Scientists have achieved a breakthrough in sampling wastewater to detect changes in COVID-19 infections within large communities.

The new method is capable of identifying the coronavirus within wastewater samples and tracking whether infection rates are growing or shrinking.

Wastewater is a "robust source" of COVID-19, according to researchers, because infected people shed the virus in their stool, meaning large amounts of virus particles are flushed down the toilet.

"This work confirms that trends in concentrations of SARS-CoV-2 RNA in wastewater tracks with trends of new COVID-19 infections in the community," said Professor Alexandria Boehm, of Stanford University.

"Wastewater data complements the data from clinical testing and may provide additional insight into COVID-19 infections within communities," added the professor, who is co-senior author of the research.

The breakthrough comes as the US faces record levels of daily transmissions, posing a significant challenge for public health authorities attempting to manage the virus.