The role of fecal aerosols in the transmission of severe acute respiratory syndrome coronavirus-2 has been suspected. Based on circumstantial evidence, the fecal aerosol transmission may have caused the community outbreak of COVID-19 in this high-rise building. Our epidemiologic and environmental data indicate that the infection source for patients in flat 2502 and possibly those in 2702 was probably the master bathroom of flat 1502, and virus-containing fecal aerosols were produced in the associated vertical stack during toilet flushing after use by the index patients. Yu and colleagues found that large amounts of bioaerosols were generated in a similar high-rise vertical drainage stack as a result of hydraulic interactions after the index patient flushed a toilet in the 2003 Amoy Garden SARS outbreak, although the number, size, and virus concentration in these bioaerosols remain unknown.

Researchers in China confirmed the presence of a viable virus in the feces of patients with COVID-19 and its potential infectivity using a stool specimen. A high viral load also has been detected in stool samples from patients with SARS. Bioaerosols can be controlled at the source by avoiding any potential gas leaks from the drainage system to indoor spaces To prevent fecal aerosol transmission. For example, to block fecal aerosol transmission, drainage traps, such as U-shaped water traps, should not be allowed to dry out.

Adequate hygiene in sanitary drainage is known to prevent the transmission of diarrheal diseases by the fecal-oral route. Our study also indirectly suggests the importance of bathroom ventilation and hygiene, because toilet flushing may generate fecal aerosols.