Neglected Aspects of SARS-CoV-2 Aerosol Transmission in Bathrooms of Multistory and High-Rise Buildings — Beijing Municipality, China, October 2022

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC? There is a toilet flush-soil stack-floor drain pathway of aerosol transmission in multistory and high-rise buildings, but the influencing factors are not completely clear. WHAT IS ADDED BY THIS REPORT? The poor airtightness of the connecting parts of the floor drain, as well as pressure fluctuations in the sewage pipe during toilet flushing caused by blockage of the soil stack vent, may lead to the cross-floor transmission of viral aerosols through the soil stack and floor drains. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE? In multistory and high-rise buildings, the bathroom floor drains should be kept sealed, and floor drain connecting parts should be airtight. Furthermore, the soil stack vent should not be blocked. In this way, the cross-floor transmission of viral aerosols can be effectively reduced.