Advancing health equity in wastewater-based epidemiology: A global critical review and conceptual framework

Abstract

Population health data from wastewater-based epidemiology (WBE) are being used at unprecedented scales worldwide, yet there is limited focus on how to advance health equity in the field. Addressing this gap, we conducted a critical review of published literature in PubMed, targeting studies at the intersection of WBE and health equity. Of 145 articles assessed in full-text screening, we identified 68 studies with health equity considerations. These studies spanned various spatial scales and biochemical targets, addressing domains such as study design and methodologies, ethical and social considerations, and the feasibility and implementation of WBE monitoring. We summarize and synthesize health equity-oriented considerations across the identified domains. We further propose five key considerations to advance health equity in WBE research and practice, and integrate these considerations into a conceptual framework to illustrate how they apply to major steps in the process of conducting WBE. These considerations include global inequities in WBE access, the need to prevent potential harms and stigma via data misuse (inappropriate reporting of data and potential use of WBE for criminal surveillance), and the importance of regulation and community engagement, particularly amidst the growing privatization of WBE, especially in the United States.

Fig. 1

Global distribution of studies collected in review. All 145 studies included for full text extraction are represented in this map. Legend represents a heatmap of the number of studies included in each country. Map was generated using the ggplot, geom_map function in R version 4.2.2.

Fig. 2

Heatmap depicting cross cutting nature of health equity domains identified. All 68 studies classified with health equity considerations are shown on the left axis grouped by primary domain. Country/location, the year of publication (2012–2019 vs 2020–2023), empirical nature of the study (yes vs no), whether the study was health equity motivated (yes vs no), presence of multiple targets of monitoring (yes vs no), type of targets (SARS-CoV-2, illicit drugs, prescription drugs, biomarkers/metabolites, other), multiple scales of monitoring (yes vs no), spatial scale resolution (at the wastewater treatment plant level (WWTP), neighborhood sewer hole, building level, upstream location) is indicated for each study. A secondary theme was classified for each study (if present), by having two authors identify a potential secondary theme (RB, SM) and having a third author adjudicate this decision (TC). In total, 14 studies had a primary motivation to look at health inequities between groups or countries, 39 were motivated by another health equity issue, and 7 were not motivated by health equity but had a health equity consideration elsewhere in the manuscript (see Table S3).

Fig. 3

Overview of the conceptual framework for incorporating health equity into wastewater-based epidemiology research and practice. Key avenues for intervention along the cycle of WBE monitoring, data production and use include during site selection and sampling, establishing of laboratory techniques, data analysis and modeling, public health reporting, and public health action. We also introduce cross-cutting recommendations for ethics equity and social considerations to be considered across all stages, and highlight that these considerations should depend on/interact with the spatial scale, target, and setting in which WBE is implemented.