Survivability of Delta and Omicron variants of SARS-CoV-2 in wastewater

Samendra P Sherchan; Ocean Thakali; Luisa A Ikner; Charles Gerba; Eiji Haramoto

doi:10.1016/j.watres.2023.120644

Survivability of Delta and Omicron variants of SARS-CoV-2 in wastewater

Water Res. 2023 Nov 1:246:120644. doi: 10.1016/j.watres.2023.120644. Epub 2023 Sep 18.

Authors

Samendra P Sherchan¹, Ocean Thakali², Luisa A Ikner³, Charles Gerba³, Eiji Haramoto⁴

Affiliations

¹ Organization for Public Health and Environment Management, Lalitpur, Bagmati, Nepal; Department of Environmental Science, University of Arizona, Tucson, AZ, United States; WEST Center, University of Arizona, Tucson, AZ, United States; Interdisciplinary Center for River Basin Environment, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan; Department of Environmental Health, Tulane University, New Orleans, LA 70112, United States; Center of Research Excellence in Wastewater-based Epidemiology, Morgan State University, Baltimore, MD 21251, United States. Electronic address: samendra.sherchan@morgan.edu.
² Organization for Public Health and Environment Management, Lalitpur, Bagmati, Nepal.
³ Department of Environmental Science, University of Arizona, Tucson, AZ, United States; WEST Center, University of Arizona, Tucson, AZ, United States.
⁴ Interdisciplinary Center for River Basin Environment, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511, Japan.

PMID: 37844338
DOI: 10.1016/j.watres.2023.120644

Abstract

Concerns of fecal-aerosol transmission of coronavirus disease 2019 (COVID-2019) coupled with increased transmissibility and disease severity of Delta and Omicron variants of concern (VOC) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), suggest studies on survival of VOC in wastewater are warranted. To the best of our knowledge, this is the first study to investigate the survivability of Delta and Omicron VOC in filtered and unfiltered raw wastewater, and secondary effluent at room temperature (23 °C). The time required for 90 % inactivation (T₉₀) of Delta and Omicron VOC in unfiltered raw wastewater was calculated as 17.7 and 15.3 h, respectively. Rapid inactivation of VOC in wastewater and inability to isolate SARS-CoV-2 in wastewater suggest risks from fecal-aerosol transmission are low. Nevertheless, high transmissibility of VOC cautions overruling fecal-aerosol transmission of COVID-19. Future studies on survival of SARS-CoV-2 in wastewater should attempt viral culture by spiking feces collected from COVID-19 infected patients into wastewater to match the real-world scenario.

Keywords: Delta; Inactivation; Omicron; Persistence; SARS-COV-2; Variants of concern.

MeSH terms

COVID-19*
Humans
Respiratory Aerosols and Droplets
SARS-CoV-2*
Wastewater

Substances

Wastewater

Supplementary concepts

SARS-CoV-2 variants