Expansion of a low-cost, saliva-based PCR test for the detection of mpox virus

• DOI: 10.1101/2023.06.12.23291295
• Publication Date: 2023-06-21T02:10:10Z
• Authors: Russell J Thomas; Orchid M. Allicock; Devyn Yolda-Carr; Katherine Fajardo; Sydney A. Steel; Chessley B. Black...; Theresa Zepeda; Maurice Brownlee; Shyam Saladi; James Parkin; Anne L. Wyllie

ABSTRACT Background Current recommendations for the diagnosis of mpox rely on lesion-swabs as gold-standard specimen type, even though many patients experience symptoms prior to lesion-onset. Alternative sample types, such saliva, which enable earlier detection could bolster response by mitigating transmission and facilitating access antiviral treatments. Methods We evaluated five PCR assays compared their DNA extracted from 30 saliva specimens collected in Spectrum SDNA-1000 tubes. sequenced seven mpox-positive samples assessed concordance with primers probes assays. Following, we incorporated these into a simplified, extraction-free protocol evaluate its feasibility testing raw (unsupplemented) samples. To further explore potential this approach, investigated stability diluted 1:10 1:100 mpox-negative after storage at 4°C, room temperature (∼19°C), 30°C, 40°C 72 hours through simulated shipping conditions. Results Despite identifying three nucleotide substitutions CDC’s Monkeypox virus Generic Real-Time Test’s primer sequences, observed no difference mean Ct-values generated between successfully each assay our saliva-based protocol. Detection following ∼19°C, 30°C remained relatively stable 24-48 Conclusions This pilot investigation supports flexible, saliva-based, test promising approach diagnosis, outbreak or ongoing surveillance mpox. With remaining temperatures, sampling simplified reduce diagnostic costs, increase address hurdles low- middle-income countries.