Using Wastewater Surveillance to Compare COVID-19 Outbreaks during the Easter Holidays over a 2-Year Period in Cape Town, South Africa

Nomfundo Mahlangeni; Renée Street; Suranie Horn; Angela Mathee; Noluxabiso Mangwana; Stephanie Dias; Jyoti Rajan Sharma; Pritika Ramharack; Johan Louw; Tarylee Reddy; Swastika Surujlal-Naicker; Sizwe Nkambule; Candice Webster; Mongezi Mdhluli; Glenda Gray; Christo Muller; Rabia Johnson

doi:10.3390/v15010162

Using Wastewater Surveillance to Compare COVID-19 Outbreaks during the Easter Holidays over a 2-Year Period in Cape Town, South Africa

Viruses. 2023 Jan 5;15(1):162. doi: 10.3390/v15010162.

Authors

Nomfundo Mahlangeni¹, Renée Street^{1

2}, Suranie Horn³, Angela Mathee^{1

2}, Noluxabiso Mangwana^{4

5}, Stephanie Dias⁴, Jyoti Rajan Sharma⁴, Pritika Ramharack^{4

6}, Johan Louw^{4

7}, Tarylee Reddy⁸, Swastika Surujlal-Naicker⁹, Sizwe Nkambule¹, Candice Webster¹, Mongezi Mdhluli¹⁰, Glenda Gray¹¹, Christo Muller^{4

5

12}, Rabia Johnson^{4

12}

Affiliations

¹ Environment & Health Research Unit, South African Medical Research Council (SAMRC), Johannesburg 2028, South Africa.
² Environmental Health Department, Faculty of Health Sciences, University of Johannesburg, Johannesburg 2028, South Africa.
³ Occupational Hygiene and Health Research Initiative, North-West University, Potchefstroom 2531, South Africa.
⁴ Biomedical Research and Innovation Platform (BRIP), South African Medical Research Council (SAMRC), Tygerberg 7505, South Africa.
⁵ Department of Microbiology, Stellenbosch University, Stellenbosch 7600, South Africa.
⁶ Discipline of Pharmaceutical Sciences, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4001, South Africa.
⁷ Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa.
⁸ Biostatistics Research Unit, South African Medical Research Council (SAMRC), Durban 4091, South Africa.
⁹ Scientific Services, Water and Sanitation Department, City of Cape Town Metropolitan Municipality, Cape Town 8000, South Africa.
¹⁰ Chief Research Operations Office, South African Medical Research Council (SAMRC), Tygerberg 7050, South Africa.
¹¹ Office of the President, South African Medical Research Council (SAMRC), Tygerberg 7050, South Africa.
¹² Division of Medical Physiology, Faculty of Medicine and Health Sciences, Centre for Cardio-Metabolic Research in Africa, Stellenbosch University, Stellenbosch 7600, South Africa.

Abstract

Wastewater surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has shown to be an important approach to determine early outbreaks of infections. Wastewater-based epidemiology (WBE) is regarded as a complementary tool for monitoring SARS-CoV-2 trends in communities. In this study, the changes in the SARS-CoV-2 RNA levels in wastewater during Easter holidays in 2021 and 2022 in the City of Cape Town were monitored over nine weeks. Our findings showed a statistically significant difference in the SARS-CoV-2 RNA viral load between the study weeks over the Easter period in 2021 and 2022, except for study week 1 and 4. During the Easter week, 52% of the wastewater treatment plants moved from the lower (low viral RNA) category in 2021 to the higher (medium to very high viral RNA) categories in 2022. As a result, the median SARS-CoV-2 viral loads where higher during the Easter week in 2022 than Easter week in 2021 (p = 0.0052). Mixed-effects model showed an association between the SARS-CoV-2 RNA viral loads and Easter week over the Easter period in 2021 only (p < 0.01). The study highlights the potential of WBE to track outbreaks during the holiday period.

Keywords: Easter holidays; SARS-CoV-2; wastewater surveillance; wastewater treatment plants.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

COVID-19* / epidemiology
Holidays
Humans
RNA, Viral / genetics
SARS-CoV-2 / genetics
South Africa / epidemiology
Wastewater
Wastewater-Based Epidemiological Monitoring

Substances

Wastewater
RNA, Viral

Grants and funding

This research was funded by the South African Medical Research Council, grant number 40118; Michael & Susan Dell Foundation, grant number 96829; National Research Foundation of South Africa, grant number 138011.