This is a summary, written by members of the CITF Secretariat, of:
Akingbola S., Fernandes R., Borden S., Gilbride K., Oswald C., Straus S., Tehrani A., Thomas J., Stuart R. Early identification of a COVID-19 outbreak detected by wastewater surveillance at a large homeless shelter in Toronto, Ontario. Canadian Journal of Public Health. (2022). doi: 10.17269/s41997-022-00696-8.
The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.
A CITF-funded study published in the Canadian Journal of Public Health, from Dr. Sharon Straus (University of Toronto) and her team, shows that wastewater surveillance was an effective technique for detecting an outbreak of COVID-19 in a Toronto homeless shelter before cases were otherwise identified. This process served as an early warning signal and allowed the timely preventive screening of residents.
Wastewater surveillance combined with traditional surveillance could provide greater responsiveness and health protection within community settings, according to the paper. Real-time monitoring at the shelter level was particularly valuable because:
- Shelters are congregate settings where SARS-CoV-2 can spread rapidly and yield high numbers of cases.
- Under-housed residents have substantial medical and social vulnerabilities that place them at higher risk of poor COVID-19 outcomes.
- Shelters often house transient populations, so routine clinical testing and vaccination may be difficult to implement.
The Toronto homeless shelter under study has been piloting a SARS-CoV-2 wastewater surveillance program since January 2021. Wastewater samples have been collected twice a week and analyzed by PCR testing to detect the presence of the virus. In late August 2021, the first positive wastewater signal was detected despite no known clinical cases. Less than a week later, the first COVID-19 case was reported and an outbreak was declared.