To inform the development of global wastewater monitoring systems, we surveyed programmes in 43 countries. Most programmes monitored predominantly urban populations. In high-income countries (HICs), composite sampling at centralised treatment plants was most common, whereas grab sampling from surface waters, open drains, and pit latrines was more typical in low-income and middle-income countries (LMICs). Almost all programmes analysed samples in-country, with an average processing time of 2·3 days in HICs and 4·5 days in LMICs. Whereas 59% of HICs regularly monitored wastewater for SARS-CoV-2 variants, only 13% of LMICs did so. Most programmes share their wastewater data internally, with partnering organisations, but not publicly. Our findings show the richness of the existing wastewater monitoring ecosystem. With additional leadership, funding, and implementation frameworks, thousands of individual wastewater initiatives can coalesce into an integrated, sustainable network for disease surveillance—one that minimises the risk of overlooking future global health threats.

Introduction

Despite decades of funding being directed into global infectious disease surveillance, and warning signs that came from both traditional and non-traditional data sources, much of the world was caught off-guard by the rapid spread of SARS-CoV-2 globally.1,2 The pandemic would potentially have unfolded differently if there had been a dedicated surveillance system that was on constant alert, continuously transmitting information about existing and emerging pathogens circulating across the globe. With such a system in place, experts would have identified SARS-CoV-2 far more quickly. Even if pandemic spread was inevitable, health-care systems could have better prepared for the fallout with more advanced notice, saving countless lives. Wastewater monitoring is an approach to disease surveillance that offers a foundation for providing early warnings for known and novel health threats via costeffective, objective measures of health obtained from non-invasive, anonymous community-level sampling. Although wastewater monitoring programmes have greatly increased in number as public health officials across the globe realised the benefits of such data to inform pandemic management, recognised frameworks for global disease surveillance have yet to be developed and adopted. Lessons from the Global Polio Eradication Initiative and smallpox eradication programmes make clear that global coordination, adaptable toolkits, and data-sharing standards are crucial components of a successful global health programme.3 Outside of polio eradication efforts, the current wastewater ecosystem remains disjointed, largely because monitoring emerged in a grassroots manner, often driven by local and regional needs to rapidly assess SARS-CoV-2 circulation. Programmes operating in isolation or within small, informal networks, particularly those in low-income and middle-income countries (LMICs), are not visible to the wider wastewater community. Although progress has been made to highlight global wastewater monitoring efforts,4–6 a comprehensive view of programmes’ methods, analytical approaches, and data sharing practices is absent. Here, we present the results of a survey of 43 countries to characterise the landscape of global wastewater monitoring. We summarise the range of approaches used for implementation and provide information to support the development of an integrated wastewater monitoring network.