Monitoring COVID‐19 through SARS‐CoV‐2 quantification in wastewater: progress, challenges and prospects

Abstract

SummaryWastewater‐Based Epidemiology (WBE) is widely used to monitor the progression of the current SARS‐CoV‐2 pandemic at local levels. In this review, we address the different approaches to the steps needed for this surveillance: sampling wastewaters (WWs), concentrating the virus from the samples and quantifying them by qPCR, focusing on the main limitations of the methodologies used. Factors that can influence SARS‐CoV‐2 monitoring in WWs include: (i) physical parameters as temperature that can hamper the detection in warm seasons and tropical regions, (ii) sampling methodologies and timetables, being composite samples and Moore swabs the less variable and more sensitive approaches, (iii) virus concentration methodologies that need to be feasible and practicable in simpler laboratories and (iv) detection methodologies that should tend to use faster and cost‐effective procedures. The efficiency of WW treatments and the use of WWs for SARS‐CoV‐2 variants detection are also addressed. Furthermore, we discuss the need for the development of common standardized protocols, although these must be versatile enough to comprise variations among target communities. WBE screening of risk populations will allow for the prediction of future outbreaks, thus alerting authorities to implement early action measurements.

Monitoring of Enterovirus D68 Outbreak in Israel by a Parallel Clinical and Wastewater Based Surveillance

“…However, recently developed pre-extraction procedures significantly reduce the presence of inhibitors while concentrating the target RNA, thereby improving the WW-based test sensitivity [ 28 , 29 ]. This approach has been used successfully since the onset of the COVID-19 pandemic for surveillance and epidemiological studies of SARS-CoV-2 [ 6 ]. It should be noted that this approach might be biased by rain effects in wastewater systems that collect runoff water.…”

“…Wastewater-based epidemiology (WBE) is a useful tool to monitor the circulation of enteric viruses and their variants, such as Poliovirus [ 5 ]. Since the beginning of the COVID-19 pandemic, the WBE approach has been applied to study SARS-CoV-2 epidemiology and gradually has become more widely used worldwide [ 6 ].…”

Sewage surveillance for SARS-CoV-2: Molecular detection, quantification, and normalization factors

“…To get detectable levels of viral nucleic acid, a large volume sampling of more than 1 L is required for the concentration step [ 18 ]. The sample technique and time of sampling are critical elements for using WBE, since they can affect data interpretation and possible cross-study comparisons [ 19 ]. Majority of research have concentrated on water samples, both small and large grab samples [ 20 , 21 , 22 ] as well as time or flow proportional composite samples [ 22 , 23 , 24 ].…”

SARS-CoV-2 Variability in Patients and Wastewaters—Potential Immuno-Modulation during the Shift from Delta to Omicron

“…Thus, due to the co-circulation of various SARS-CoV-2 strains within populations and in infected individual subjects, new variants with advantageous mutations and/or composite mutations can emerge. Subsequent new viral variants might carry new biological properties, such as viral escape from host-related immune response [ 6 ], specific human tissue or animal tropism [ 7 ], and possible modulations in SARS-CoV-2 properties in the environment through the Spike protein influencing viral behavior in samples, such as wastewaters [ 8 ].…”

“…In this context, additionally to the detection and sequencing of SARS-CoV-2 strains in patients, a promising approach to monitor the viral spreading is wastewater-based epidemiology (WBE) because of viral fecal shedding from infected patients. The exploration of viral genetic variability in human samples has been considered as a key tool by health workers, while WBE could allow us to take into account not only the symptomatic patients but also the asymptomatic infected people for a global survey of SARS-CoV-2 genomic evolution [ 8 ].…”