Awarded entry of the HKIE 50th Anniversary Legacy Award - Grand Award (Innovation Category)

To combat the COVID-19 pandemic, the HKSAR Government has established an inter-departmental working team comprising over 400 staff with various specialties from the Environmental Protection Department, Drainage Services Department and Department of Health. This team launched a unique city-wide sewage surveillance programme for real-time COVID-19 monitoring and forecast.

A comprehensive surveillance network was strategically established with 154 sampling sites at sewage manholes, covering 80% of the city’s population. Sewage samples were collected under a two-day cycle for analysis of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Through the development of statistical models which accurately forecasted the number of new cases two to four days ahead, real-time analysis of spatial and temporal distribution of viral concentrations was achieved. Intervention measures could be precisely implemented on time through a tiered approach to prioritise limited resources to high-risk areas up to street-block level. In addition, models also helped assess whether and when the city would reach community immunity.

Based on the results, 306 statutory Restriction-Testing Declarations were issued and more than 26,700 asymptomatic patients were identified, who could otherwise have been left unattended. Correspondingly, Hong Kong successfully contained the disease with the number of daily new cases reduced from over 70,000 in early March 2022 to fewer than 300 within only two months, without city lockdown. This programme continues to serve the community during the post-pandemic period to enhance preparedness for possible outbreaks of any sewage-borne diseases including influenza.

This unique example from Hong Kong demonstrated how public health policy can be shaped by environmental science and engineering at any epidemic stage through an innovative and cost-effective approach. The programme’s flexibility also enables its application to other cities regardless of population size and economic scale.

Aspects of the programme