A novel spatiotemporal approach to COVID-19 surveillance

A recent Master’s thesis explored a new way to understand the spread and possible control of COVID-19 better by combining wastewater measurements and other epidemiological indicators.

Past research in wastewater-based epidemiology has shown that collecting and analysing wastewater can improve the surveillance of diseases such as norovirus, poliovirus, and hepatitis.

However, little research has been done to examine the relationship between the concentration of pathogens in wastewater and other epidemiological indicators.

This recent study presented a novel approach to fill this gap, with a focus on SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2, i.e., the virus causing COVID-19).

The research explored several epidemiological indicators, such as confirmed cases, hospitalisations, and deaths, across multiple geographical scales in the Netherlands.

The COVID-19 dashboard

Information on SARS-CoV-2 wastewater concentration and relevant epidemiological indicators was gathered from the COVID-19 dashboard managed by the Dutch National Institute for Health and Environment (RIVM).

Established shortly after the outbreak of COVID-19 in 2020, the dashboard hosts information about the virus and provides insight into the spatial and temporal patterns of its transmission.

Down to the municipal level

Surveillance of SARS-CoV-2 in wastewater in the Netherlands started in the first quarter of 2020, with weekly measurements of the number of virus particles in some selected Wastewater Treatment Plants (WWTPs).

By mid-2021, the viral load measurement was extended to over 300 WWTP. In the study, the weekly readings of these wastewater measurements were disaggregated to the municipal level, and other epidemiological indicators were organised in the same manner.

Spatio-temporal analysis of SARS-CoV-2 pathogens in wastewater (upper maps) and reported positive cases (lower maps) across municipalities in the Netherlands.
Hassan (2021)

Results

The analyses confirm that SARS-CoV-2 wastewater data is a useful complementary epidemiological indicator to explore the spatiotemporal variation of the SARS-CoV-2 transmission intensity.

The research also showed that analysing wastewater data and other epidemiological indicators at the municipal level can be useful in monitoring SARS-CoV-2 transmission intensity in smaller geographical areas. It can serve to identify infection hot spots and facilitate timely location-specific interventions to contain the virus.

The study's most interesting finding is that in about half of the municipalities in the Netherlands, an increase in SARS-CoV-2 wastewater RNA concentration precedes increases in weekly positive cases by one or two weeks.

These results are useful in providing more insight into the spatial and temporal transmission of the SARS-CoV-2 virus and help public health officials make informed decisions.

Applicability

The analysis of the SARS-CoV-2 wastewater data and other epidemiological indicators makes this study interesting to water research, health research, and geoinformation science fields.

The study also benefits RIVM, which has proclaimed sewage surveillance a viable tool for enabling early detection in the event of localised outbreaks and for recognising new variants.

The novel spatiotemporal approach followed in this study shows that SARS-CoV-2 wastewater concentration data has added value as a complementary epidemiological indicator to monitor COVID-19 transmission intensity at the municipal level. Besides offering valuable insights into the COVID-19 pandemic, the same approach can also be applied to address future health challenges.

Read the full master's thesis by following the link below: