Differentiating between the possibility and probability of SARS-CoV-2 transmission associated with wastewater: empirical evidence is needed to substantiate risk

People infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shed the virus and its genetic material via their sputum, nasopharyngeal secretions, saliva, urine and feces (Cevik et al.2021). Hence, public health and water quality scientists throughout the world have been monitoring untreated and/or primary treated wastewater and sludge for the surveillance of SARS-CoV-2 in communities (https://arcg.is/1aummW). Numerous reviews have discussed the possibility of SARS-CoV-2 transmission to humans from exposure to wastewater or waters receiving untreated or inadequately treated wastewater based on limited empirical evidence (Adelodun et al. 2020;Bilal et al. 2020;Olusola-Makinde and Reuben 2020;Elsamadony et al. 2021;Khorram-Manesh, Goniewicz and Burkle 2021;Shutler et al. 2021). Multiple transmission routes have been suggested, including waterborne transmission, airborne transmission, contact with contaminated surfaces (fomites) and subsequent touching of mucous membranes such as the mouth, nose, or eyes. Herein, we briefly summarize the empirical evidence pertaining to the transmission of SARS-CoV-2 associated with wastewater exposure.