# Seasonal Variations in the Occurrence of SARS-CoV-2 RNA Recovered from Wastewater Treatment Facilities (WWTFs) Within South Africa

## TL;DR

This study analyzed wastewater in South Africa over a year to track SARS-CoV-2 RNA levels across seasons and found higher viral presence in winter.

## Contribution

The study provides the first seasonal analysis of SARS-CoV-2 RNA in wastewater from South Africa, highlighting its potential for public health surveillance.

## Key findings

- SARS-CoV-2 RNA was detected in 44% of wastewater samples, with concentrations ranging from 700 to 40,000 GC/mL.
- Higher viral genome copies were observed in winter compared to other seasons.
- No strong correlation was found between wastewater viral levels and reported clinical cases.

## Abstract

Several researchers have documented the occurrence of the unfamiliar severe acute respiratory syndrome coronavirus 2 ribonucleic acid (also known as SARS-CoV-2 RNA) in various raw wastewater (WW) samples analyzed globally. The efficiency of strategic WW-based epidemiology (WBE) approach as a timely cautioning tool for human coronavirus disease-2019 (COVID) and other similar outbreaks is highly promising. This strategy offers a cost-effective, population-wide surveillance tool that can detect rising case trends, from days to weeks before clinical reports, thus enabling proactive public health interventions. This study aimed to detect the occurrence of the viral genome in WW over four seasons, which contributes to the database for multi-plant surveillance research in South Africa. About 480 WW influent samples were amassed from ten sampling points situated in nine wastewater treatment facilities (WWTFs) in Amathole District Municipality (ADM) located in the Province of Eastern Cape (EC), South Africa (SA). The study was carried out for a period of one year. Quantitative real-time polymerase chain reaction (i.e., RT-PCR) was operated to identify the viral genomes in the respective total RNA samples. Of the 480 extracted RNA samples, 210 (44%) were positive with viral genome copies (gc) that ranged from 700 to 40,000 GC/mL. Our results were contrasted with existing COVID-19-positive cases throughout the COVID omicron wave in the ECP. Variations in gc were observed across different seasons, with the highest GC observed in winter. In contrast, there were significant inconsistencies in the existing data of COVID-19 clinical cases, thus indicating no connection between both data. However, with more similar studies, advanced innovative WBE strategies could possibly act as prompt warning tools to signal public health officials about potential future outbreaks.