Keeping pace with an infectious disease outbreak is like solving a complex puzzle in a race against time. The good news is that there can be vital clues lying right beneath our feet—sewage systems can provide early warnings by providing critical epidemiological information to help keep communities safe.
Xian Jun Loh, Executive Director at A*STAR’s Institute of Materials Research and Engineering (IMRE), listed some advantages of wastewater-based epidemiology, or WBE: “Firstly, it provides a holistic view of infection rates within a community, including asymptomatic cases.”
“Secondly, it is cost-effective and can detect outbreaks early. Moreover, it complements clinical testing by monitoring a larger population,” added Loh.
Together, Loh explained, those two aspects of WBE can be used to prompt swift public health actions, like focused testing, contact tracing and isolation protocols. This proactive strategy can effectively reduce a virus' spread and avert large-scale community outbreaks.
Using the COVID-19 pandemic as a framework, Loh teamed up with Ady Suwardi and other IMRE colleagues to provide insights on the latest knowledge about detecting and measuring SARS-CoV-2 in wastewater.
SARS-CoV-2 is shed by both symptomatic and asymptomatic COVID-19 patients. In certain instances, the virus was still found in faecal samples for up to 10 weeks after it was no longer detectable in throat swabs or urine samples.
They reported that despite its potential, however, community-level surveillance using WBE can be challenging—factors like temperature, pH levels, initial virus concentration and chemical pollutants in wastewater can affect the accuracy of readings.
“Statistical analysis and normalisation techniques were applied to account for these variables, ensuring consistency in the findings,” explained Loh.
Also, because wastewater environments are in a state of constant flux, viral loads in wastewater samples tended to vary significantly, said Loh. “Different researchers addressed them by using multiple detection methods, spiking control samples and cross-referencing results with clinical data to validate their findings.”
In their review, the team also provided the field with guidance for using wastewater surveillance in epidemiological studies to better understand and control COVID-19 outbreaks. They proposed establishing standardised procedures and guidelines for data reporting.
“Collaboration among research communities and regulatory bodies can facilitate harmonisation, enabling effective use of this tool in the fight against COVID-19,” commented Loh.
The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering (IMRE).