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. 2023 Jan 5;15(1):162.
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

Nomfundo Mahlangeni  1 , Renée Street  1   2 , Suranie Horn  3 , Angela Mathee  1   2 , Noluxabiso Mangwana  4   5 , Stephanie Dias  4 , Jyoti Rajan Sharma  4 , Pritika Ramharack  4   6 , Johan Louw  4   7 , Tarylee Reddy  8 , Swastika Surujlal-Naicker  9 , Sizwe Nkambule  1 , Candice Webster  1 , Mongezi Mdhluli  10 , Glenda Gray  11 , Christo Muller  4   5   12 , Rabia Johnson  4   12
Affiliations

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

Nomfundo Mahlangeni et al. Viruses. .

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.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The funders had no role in the design of the study, in the collection, analyses, or interpretation of data.

Figures

Figure 1
Figure 1
SARS-CoV-2 RNA viral load during the Easter week in 2021 and Easter week in 2022.
Figure 2
Figure 2
SARS-CoV-2 RNA viral load in wastewater during the (A) Easter period in 2021 and (B) Easter period in 2022. Red vertical dotted line indicates the Easter Monday in 2021 and 2022. * p < 0.05, ** p < 0.01, and *** p < 0.001 viral load compared between Easter week (Easter Monday) and non-Easter weeks.
Figure 3
Figure 3
COVID-19 confirmed cases (A) percent positivity test rate (B) in the City of Cape Town during the Easter period in 2021 and Easter period in 2022. Red and blue vertical dashed line and boxes indicates the Easter Monday in 2021 and 2022, respectively.
Figure 3
Figure 3
COVID-19 confirmed cases (A) percent positivity test rate (B) in the City of Cape Town during the Easter period in 2021 and Easter period in 2022. Red and blue vertical dashed line and boxes indicates the Easter Monday in 2021 and 2022, respectively.
See this image and copyright information in PMC

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