Dataset of SARS-CoV-2, influenza A and influenza B virus content in wastewater samples from wastewater treatment plants in Sweden

This is a metadata record for a continuously updated dataset of SARS-CoV-2 RNA data in wastewater in Uppsala. 

The dataset is part of a research study led by associate professor Anna J. Székely (SLU, Swedish University of Agricultural Sciences) and her research groups in collaboration with Uppsala Vatten. The research group is part of the Environmental Virus Profiling Research Area of the SciLifeLab National COVID-19 Research Program.

The data is generated by weekly SARS-CoV-2, influenza A and influenza B virus measurements in wastewater samples from Sweden. The monitoring started in Uppsala in August 2020, while other places joined the program later. For all places, raw, untreated wastewater samples representative of a single day (24 hours) are collected by flow compensated samplers. All measurements represent only 1 day except for Uppsala, where since week 16, 2021 the measurements represent 1 week as samples are collected each day and then combined flow-proportionally into 1 composite weekly sample.

The samples are processed according to standard methods. Briefly, the viral genomic material is concentrated and extracted by the direct capture method using the Maxwell RSC Enviro TNA kit (Promega) and the copy number of SARS-CoV-2 genomes is quantified by RT-qPCR using the CDC RUO nCOV N1 assay (IDT DNA). To correct for variations in population size and wastewater flow, we also quantify the pepper mild mottle virus (PMMoV) which is the most abundant RNA virus in human feces and serves as an estimator of human fecal content (Symonds et al., 2019). For more about the evaluation of this normalization method, please consult the corresponding publication: Isaksson et al. (2022). The data is presented on the graph as the ratio of the copy numbers measured by the N1 and PMMoV-assays multiplied by 10^4. As N1 copy number is a proxy for SARS-CoV-2 virus content in the wastewater and PMMoV is a proxy of the fecal content, which is related to the contributing population, this ratio can be considered as proxy of the prevalence of infections in the population of the wastewater catchment area.

The dataset is available as part of the Environmental Virus Profiling data section "The amount of SARS-CoV-2 virus in wastewater across Sweden". It can be found here and downloaded under the heading "Dataset". Note that the dataset is preliminary. The team is still conducting method efficiency checks that might slightly affect the final results.