Tracking cryptic SARS-CoV-2 lineages detected in NYC wastewater

Tracking SARS-CoV-2 genetic diversity is strongly indicated because diversifying selection may lead to the emergence of novel variants resistant to naturally acquired or vaccine-induced immunity. To monitor New York City (NYC) for the presence of novel variants, we deep sequence most of the receptor binding domain coding sequence of the S protein of SARS-CoV-2 isolated from the New York City wastewater. Here we report detecting increasing frequencies of novel cryptic SARS-CoV-2 lineages not recognized in GISAID's EpiCoV database. These lineages contain mutations that had been rarely observed in clinical samples, including Q493K, Q498Y, E484A, and T572N and share many mutations with the Omicron variant of concern. Some of these mutations expand the tropism of SARS-CoV-2 pseudoviruses by allowing infection of cells expressing the human, mouse, or rat ACE2 receptor. Finally, pseudoviruses containing the spike amino acid sequence of these lineages were resistant to different classes of receptor binding domain neutralizing monoclonal antibodies. We offer several hypotheses for the anomalous presence of these lineages, including the possibility that these lineages are derived from unsampled human COVID-19 infections or that they indicate the presence of a non-human animal reservoir. To monitor the presence of novel SARS-CoV-2 variants in New York City, Smyth et al. perform deep-sequencing of the receptor binding domain of S protein in wastewater samples and find novel cryptic lineages containing mutations affecting ACE2-tropism and showing decreased neutralization by antibodies.

Automated summary

Tracking the genetic diversity of SARS-CoV-2 is important to monitor the emergence of novel variants resistant to immunity. The researchers detected increasing frequencies of novel cryptic SARS-CoV-2 lineages in the New York City wastewater, containing mutations rarely observed in clinical samples. These lineages share mutations with the Omicron variant and have expanded tropism and resistance to neutralizing antibodies.