Willingness to pay for nationwide wastewater surveillance system for infectious diseases in Japan

COVID-19 motivated the US and the European Union to establish a regular pathogen surveillance system at wastewater treatment plants, but other countries, including Japan, have been reluctant to adopt such a system. To determine whether a continuous pathogen surveillance system at wastewater treatment plants is economically justifiable in Japan, we conducted a contingent valuation experiment to estimate a hypothetical willingness to pay (WTP) for such a surveillance system. To collect primary data, an online WTP experiment was administered to a nationally representative sample in Japan in spring 2023 (N = 2,457). Results indicated that mean WTP was US $23.47 (Median $8.83) per household per year, and that around 97% of individuals had a non-zero WTP. The monetary valuation aggregated to the national level ($497 million based on the median value) exceeds the likely costs of maintaining the system in Japan ($33 million). Based on the population’s valuation of the nationwide wastewater surveillance system, its establishment would be economically justifiable in Japan. Our results are expected to inform stakeholders in Japan, the US, the European Union, and other countries considering expanding or maintaining wastewater surveillance systems that are applicable for diverse infectious diseases including COVID-19. For a future epidemic with uncertain risks, the surveillance systems’ economic efficiency (e.g., cost-effectiveness and return-on-investment) is difficult to assess. Eliciting taxpayers’ WTP can be informative for that purpose.