Making waves: Moving beyond the 1 in 10,000 benchmark in quantitative microbial risk assessment (QMRA) through evidence-informed risk approaches and systems decision-making

Abstract

Public health decision-making for the management of infectious diseases quantifies human risks, typically segmented by vulnerability groupings to evaluate risk management interventions. While many paradigms are available for evaluating risks and their tradeoffs, relatively few are used in practice. Many sectors such as water reuse rely on benchmark approaches for risk, such as 1 in 10,000 infections per person per year. As risk-risk tradeoffs are increasingly considered in quantitative microbial risk assessments (QMRA), there is a need to broaden acceptability criteria beyond such approaches to consider holistic aspects of decision-making such as broader sustainability and cost impacts, and fairness. Evidence-based benchmarks can be incorporated into a systems approach to risk management by providing a more integrated alternative to strict policy-recommended one-size-fits-all targets. Potential research gaps for both existing and forward-looking metrics of acceptable microbial risk and alternative approaches are identified, with water reuse as a focus area.