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Peer reviewedOpen accessCOVID-19SARS

Inferring transmission fitness advantage of SARS-CoV-2 variants of concern from wastewater samples using digital PCR, Switzerland, December 2020 through March 2021

Eurosurveillance·

Lea Caduff, David Dreifuss, Tobias Schindler, Alexander J Devaux, Pravin Ganesanandamoorthy, Anina Kull, Elyse Stachler, Xavier Fernandez-Cassi, Niko Beerenwinkel, Tamar Kohn, Christoph Ort, Timothy R Julian

DOI
10.2807/1560-7917.es.2022.27.10.2100806
PMID
PMCID
OpenAlex
W4220863572
Study type
Genomic study
Publisher
European Centre for Disease Control and Prevention (ECDC)
Article type
journal-article
Integrity
current

Why this research matters now

The findings support the potential use of targeted digital PCR in wastewater to monitor variant frequency and may indicate changes earlier than clinical sequencing. The evidence presented is specific to the reported Zurich analysis and does not establish performance in other settings.

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Structured evidence summary

Research question

The study examined whether wastewater measurements of two SARS-CoV-2 deletion markers could identify Alpha, Beta, and Gamma variant signatures and estimate the transmission fitness advantage of Alpha.

Study design

The authors developed drop-off RT-dPCR assays and a statistical analysis approach for evaluating temporal changes in variant-associated deletion markers in wastewater. The work is described as a genomic study using wastewater samples and comparison with clinical sequencing estimates.

Population and setting

The analysis used wastewater samples from Zurich, Switzerland, collected from December 2020 through March 2021. The abstract also refers to a comparison with clinical sequencing from the surrounding canton.

Main findings

The estimated transmission fitness advantage for Alpha was 0.34 using the spike deletion marker and 0.53 using the ORF1a deletion marker. These estimates were reported as consistent with a clinical-sequencing estimate of 0.49 from the surrounding canton.

Public-health relevance

The findings support the potential use of targeted digital PCR in wastewater to monitor variant frequency and may indicate changes earlier than clinical sequencing. The evidence presented is specific to the reported Zurich analysis and does not establish performance in other settings.

Important limitations

The evidence is based on wastewater from one Swiss setting, a defined collection period, and two deletion targets, with comparison to clinical sequencing from the surrounding canton. No explicit limitations are provided in the supplied material; this summary is therefore limited to the single-article abstract and metadata and requires the original paper for decision-grade interpretation.

GIDS interpretation

This article is discoverable as evidence concerning wastewater-based genomic monitoring and estimation of variant transmission dynamics in Switzerland. The supplied study does not confirm or characterize any live surveillance signal.

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Related GIDS surveillance

Literature context does not validate, explain, or change a surveillance signal. Exact and contextual relationships are shown separately.

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Evidence relationships

This article has 12 auditable classifier relationships to diseases, places, topics, and study design.

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