SARS-CoV-2 Surveillance in Belgian Wastewaters

Area of Science:

• Environmental science
• Public health
• Virology

Background:

• Wastewater-based surveillance is a key tool for monitoring infectious disease circulation.
• National public health authorities require robust methods to track SARS-CoV-2.
• Understanding virus dynamics in diverse populations is crucial for effective public health response.

Purpose of the Study:

• To assess the effectiveness of wastewater-based surveillance for monitoring SARS-CoV-2 in Belgium.
• To evaluate the correlation between wastewater SARS-CoV-2 concentrations and reported COVID-19 cases.
• To develop and validate alerting indicators for epidemiological assessment.

Main Methods:

• Conducted wastewater surveillance across 42 treatment plants, covering over 5 million inhabitants for 15 months.
• Collected and analyzed SARS-CoV-2 concentrations in wastewater, adjusting for rain impact and population size.
• Developed and applied three normalized indicators: High Circulation, Fast Increase, and Increasing Trend.

Main Results:

• A high correlation was observed between daily COVID-19 cases and corrected SARS-CoV-2 wastewater concentrations.
• Rain events, if uncorrected, led to underestimation of surveillance indicators.
• The developed indicators effectively monitored the fourth virus wave and complemented traditional data.

Conclusions:

• Wastewater-based surveillance provides valuable and complementary data for monitoring SARS-CoV-2.
• Adjusting for rain impact is crucial for accurate indicator performance.
• This approach offers a reliable method for national public health surveillance and risk assessment.