Quick Hits: SARS-CoV-2 Edition

Captain MARVE
 

A simple, paper-based assay – named MARVE – promises rapid colorimetric detection of SARS-CoV-2 variants (1). By using a nucleic acid strand displacement process, the assay can recognize and distinguish viral RNA mutations. The new tool represents a potential solution for the lack of scalable diagnostic tools for SARS-CoV-2 variants, which has previously hindered surveillance of mutational evolution.

Sewage science
 

Scientists have called for wastewater surveillance to spearhead epidemiological monitoring of infectious pathogens (2). They argue that wastewater testing provides a valuable population-level view of disease, shows promise in detecting antimicrobial-resistant strains, and can fill the gap where current diagnostic tests fall short.

In other wastewater news…
 

Researchers have tested the effectiveness of a new wastewater surveillance method for monitoring spatiotemporal viral dynamics (3). By deep sequencing 3,413 samples across Austria, the method was able to robustly deduct relative SARS-CoV-2 variant frequencies with high spatiotemporal resolution and reduced sample numbers and logistical effort.

Spitting distance
 

Researchers have developed an RNA-extraction-free test for rapidly detecting SARS-CoV-2 in saliva via Cas13 (4). When validated against qPCR nasal-swab samples, the test achieved 94 percent sensitivity and 100 percent specificity. Rapid point-of-care RNA testing could broaden the use of SARS-CoV-2 molecular diagnostics.

Golden chips
 

A dual method for detecting SARS-CoV-2 RNA and anti-SARS-CoV-2 antibodies in saliva and blood plasma has been developed using an electrochemical lab-on-a-chip platform (5). The user-friendly device can identify SARS-CoV-2 RNA and relevant antibodies in clinically relevant quantities, and could one day help quickly and easily monitor both infection and immune status of COVID-19 patients.