SARS-CoV-2 Aerosol Transmission Through Vertical Sanitary Drains in High-Rise Buildings — Shenzhen, Guangdong Province, China, March 2022

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC? Aerosol transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via sanitary pipelines in high-rise buildings is possible, however, there is a lack of experimental evidence. WHAT IS ADDED BY THIS REPORT? The field simulation experiment confirmed the existence of a vertical aerosol transmission pathway from toilet flush-soil stack-floor drains without water seal. This report provided experimental evidence for vertical aerosol transmission of clustered outbreaks on 18 floors of a 33-story residential building. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE? The water seal on floor drains is a necessary barrier to prevent the risk of vertical aerosol transmission of infectious disease pathogens in buildings. It is necessary not only to have a U-shaped trap in the drainage pipe, but also to be filled with water regularly.