Viral genome sequencing of wastewater can provide an early warning system of emerging SARS-CoV-2 variants that is independent of investigations of identified clinical cases, according to a new study published in mSystems, an open-access journal of the American Society for Microbiology. In the study, researchers describe the detection and quantification of variant B.1.1.7, first identified in southeast England, in sewage samples from London, United Kingdom before widespread transmission of this variant was obvious from clinical cases.