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Pilot wastewater surveillance program for COVID-19

Queensland Health has partnered with researchers from the University of Queensland and CSIRO to commence a pilot wastewater surveillance program for SARS-CoV-2, the virus that causes COVID-19. Samples of wastewater will be taken from wastewater treatment plants across Queensland and analysed for fragments of the virus. The results from this pilot program will add to the information obtained through clinical testing and enhance Queensland Health’s already comprehensive response to the COVID-19 pandemic. In delivering this program, Queensland joins other Australian states that are monitoring their wastewater for SARS-CoV-2.

Questions about the program

What is Queensland Health’s pilot wastewater surveillance program?

Queensland Health has joined forces with researchers from the University of Queensland and CSIRO to analyse samples of wastewater (sewage) for fragments of SARS-CoV-2, the virus that causes COVID-19. The pilot program is designed to take and analyse samples from wastewater treatment plants across Queensland and is intended to help inform Queensland Health’s response to the COVID-19 pandemic.

What is wastewater surveillance?

Wastewater surveillance involves taking samples of wastewater and analysing those samples for traces of genetic material from disease causing organisms. Wastewater surveillance can be used to monitor the health of whole communities, adding to the information obtained from clinical testing (e.g. swabs). Wastewater surveillance is being employed as part of the overall response to the COVID-19 pandemic as COVID-19 patients may shed viral fragments in their faeces, and from used tissues. Viral fragments can also enter the wastewater network when washed off hands and bodies via basins, sinks and showers.

Wastewater surveillance has made a significant contribution to the World Health Organisation’s Global Polio Eradication Initiative and has also been used by researchers in Australia to monitor licit and illicit drug consumption, pharmaceutical use, dietary and nutrient data and other community health parameters.

How are the sampling sites chosen?

Queensland Health has established a steering group – made up of environmental health professionals, epidemiologists and researchers - to identify sampling sites. Sampling sites are chosen based on a number of factors but the ultimate aim is to sample from sites that will provide the most useful data in the context of Queensland Health’s response to the COVID-19 pandemic.

What is the significance of a positive result?

The results from wastewater surveillance need to be considered carefully alongside other information available to Queensland Health. Detections can provide an indication there are people in a particular wastewater catchment who have a current infection with COVID-19, or who have been infected in the recent past. In addition to those who have a known infection, there may also be infected individuals who are asymptomatic (i.e. infected but with no symptoms) or pre-symptomatic (i.e. infected but without having developed any symptoms). In some instances, a positive result has the potential to provide an early warning that the virus has been introduced into an area where cases haven’t been identified previously via clinical testing.

What will Queensland Health do if SARS-CoV-2 is detected in a wastewater sample?

The response to detections will depend on the particular circumstances of the location and the population contributing to the wastewater catchment. A detection from a small sewerage catchment, particularly one with a vulnerable population (e.g. a residential aged care facility), may prompt a very rapid response from public health officers to protect the health of residents. On the other hand, an occasional detection in wastewater from an area with a large population, where there are known to be active cases or recovering cases, may not require any immediate response, but just continued monitoring.

Is wastewater surveillance practised in other areas?

Wastewater surveillance for SARS-CoV-2 is being practised in other Australian states and in many other countries around the world. Some differences exist in methods of sampling and testing but all programs aim to provide data that can help inform their respective responses to the COVID-19 pandemic.

How long will the program run for?

This Queensland Health pilot program is expected to conclude in late October 2020. Following the conclusion of the program a report will be produced with a recommendation as to whether wastewater surveillance should continue or be extended to include other disease-causing organisms or other targets of health interest or concern.

Does the presence of viral fragments in wastewater mean that the use of recycled water, or discharge of treated wastewater to receiving waters, can pose a risk to the health of the public?

The presence of fragments of SARS-CoV-2 does not mean there is ‘live’ virus, capable of causing infection, present in the wastewater. SARS-CoV-2 is easily inactivated by conventional wastewater treatment processes. There is no evidence that COVID-19 can be spread via recycled water nor via treated wastewater released to waterways.

Can councils and water utilities participate in the program?

When potential sampling sites are identified, the council or water utility that operates the wastewater treatment plant is invited to participate in the pilot program. In addition to providing access, councils and utilities assist with the deployment of samplers and collection and despatch of samples. This is a significant and appreciated contribution to the project. Testing for SARS-CoV-2 fragments in sewage is highly specialised and is not routinely available. It is not yet viable for councils or utilities to undertake their own sampling programs, and sampling of on-site wastewater treatment plants is not appropriate.

Last updated: 21 August 2020