Isolation of SARS-CoV-2 in untreated wastewater in Australia

Isolation of SARS-CoV-2 in untreated wastewater in Australia. Jefferson T, Heneghan C.

https://www.cebm.net/study/isolation-of-sars-cov-2-in-untreated-wastewater-in-australia/

Published on June 29, 2020

Reference Ahmed W, Angel N, Edson J, et al. First confirmed detection of SARS-CoV-2 in untreated wastewater in Australia: A proof of concept for the wastewater surveillance of COVID-19 in the community. Science of The Total Environment. 2020;728:138764. 2020
Study type
Country Australia
Setting Sewage
Funding Details Non reported
Transmission mode Orofecal
Exposures Wastewater

Bottom Line

SARS-CoV-2 was deleted for the first time in Australia using RT-qPCR assay, confirmed by sequencing

Evidence Summary

Some 22% of samples from one sampling point were positive. The estimated  number of infections and prevalence are strongly correlated with the log10 SARS-CoV-2 RNA copies in stool, followed by the RNA copies detected in wastewater and log10/g of feces/person/day. 

The model was least sensitive to the daily per capita flow rate of wastewater (0.042).

No mention is made of the viability of the viral material recovered, however the authors believe that with further refinements the method could be used to estimate the prevalence of asymptomatic and symptomatic cases in the population. 

What did they do?

The authors studied samples taken from two treatment plants and pumping stations around Brisbane, Queensland, Eastern Australia starting on the 24th of February until 13th of April with more frequent sampling as the epidemic curve got higher. The paper describes in detail the methods for concentrating, storing and testing the samples (not reported here). Different concentration and testing methods gave different results. The authors modelled the correlation between affluent, concentration and positivity of samples and Covid 19 cases. 

Study reliability

The study is a proof of concept and requires replication and further development. It is unclear how generalisable its results are and the tests need standardisation and development.

Clearly defined setting Demographic characteristics described Follow-up length was sufficient Transmission outcomes assessed Main biases are taken into consideration
Yes No Yes No Yes

What else should I consider?

Wastewater monitoring has great potential to provide early warning signs on how broadly SARS-CoV-2 is circulating in the community, especially in those individuals showing mild symptoms or no symptoms at all. Tests need to be standardised. This is a proof concept study which required replication. More information on the ecology of Co-V in a water environment is necessary.

About the authors

Carl Heneghan

Carl Heneghan

Carl is Professor of EBM & Director of CEBM at the University of Oxford. He is also a GP and tweets @carlheneghan. He has an active interest in discovering the truth behind health research findings

Tom Jefferson

Tom Jefferson

Tom Jefferson is a senior associate tutor and honorary research fellow, Centre for Evidence-Based Medicine, University of Oxford.