How wastewater analysis helped stop the spread of COVID-19

Analysis of Queensland's wastewater became a valuable tool during the peak of the COVID-19 pandemic.

While a grim thought for many, the ability to assess people's waste created an early warning system for Queenslanders.

By having access to wastewater, authorities were able to predict where clusters of COVID-19 might emerge and become a threat to the wider population.

Professor Kevin Thomas is the Director of the Queensland Alliance for Environmental Health Science.

He credits his team at UQ, along with its many research partners, for their surveillance work, which was instrumental in identifying COVID-19 risks in wastewater over the last two years.

Professor Thomas spoke to Research News about the success of the team's work.

What role has QAEHS's wastewater program played in the fight against COVID-19?

When talking about COVID-19, the QAEHS wastewater-program can be split into three phases.

Phase one involved initial research with CSIRO and support from the Australian Criminal Intelligence Commission (ACIC) to establish whether wastewater surveillance of SARS-CoV-2 was even feasible.

We produced the first peer-reviewed publication on the analysis of SARS-CoV-2 in wastewater and collaborated with colleagues globally to push for the approach to be developed as an early warning system.

Phase two saw us run a pilot funded by Queensland Health to establish applicability in Queensland.

Phase three involved routine surveillance of SARS-CoV-2 in catchments and sub-catchments across the state.

We have provided data to Queensland Health and its public health units on the situation within the state over the past 18 months or so.

Fortunately, Queensland has seen very few cases but the surveillance has provided early warning on a number of occasions, most notably the Indooroopilly cluster.

More broadly the CSIRO-UQ team has published a number of highly cited papers that have contributed to improving the technique and how it is applied globally.

What is the process of detecting the COVID-19 virus and illicit substances in wastewater? How is it done?

Wastewater-based epidemiology (WBE) is a monitoring approach increasingly being used to assess trends in population chemical consumption, use and exposure as well as a surveillance tool from SARS-CoV-2 during the current COVID-19 pandemic.

Toilet flushes from the community served by a catchment or sub-catchment are captured over a 24-hour period. These samples are analysed for biomarkers of interest (e.g. SARS-CoV-2 RNA or an illicit drug metabolite) depending on the type of investigation. It is possible to calculate the amount of a biomarker excreted by the catchment population and knowing the catchment’s population allows this to be normalised to the number of people in each catchment. For some exogenous biomarkers it is possible to calculate the amount of the substance consumed.

For SARS-CoV-2 we also use passive sampling devices (3D printed torpedoes that contain a membrane that captures virus RNA) which are placed up-sewer to be able to split sewer catchments.

Once detected, how is this information used? Who is it given to and what benefit does it have to the public?

Data provided on SARS-CoV-2 is given to Queensland Health and published on their dashboard.

The data informs the general public as to whether there are individuals shedding SARS-CoV-2 in their (sub-)catchments. This then allows the general public to make an informed decision as to the COVID-19 situation in their area. It will be interesting when restrictions ease to see how the data will evolve.

For illicit drugs the data is reported by the ACIC and media. The ACIC reports provide the public with relatively recent metric on drug consumption across all states and territories. It shows trends both spatially and temporally within Australia, as well as allowing comparisons with other jurisdictions.

What does the future hold for the program?

We have lots of interesting studies coming up. We have students and researchers working on many aspects of wastewater-based epidemiology for various markers of health. These include new markers of what is being used in society, how samples are collected, as well as studies that assess changes based on various factors – for example, how COVID-19 has affected illicit drug consumption, as well as other drugs.