Robotic RNA extraction for SARS-CoV-2 surveillance using saliva samples

Area of Science:

• Virology
• Molecular Biology
• Public Health

Background:

• Saliva is a viable specimen for COVID-19 surveillance due to easy collection and SARS-CoV-2 RNA detection.
• Direct-to-RT-qPCR saliva assays lack nucleic acid extraction, potentially reducing sensitivity.
• High-throughput, sensitive detection methods are needed for large-scale asymptomatic COVID-19 surveillance.

Purpose of the Study:

• To develop a high-throughput, robotic nucleic acid extraction method for sensitive SARS-CoV-2 RNA detection in saliva.
• To adapt the assay for pooled saliva samples to increase testing capacity.
• To validate a RT-qPCR test suitable for self-collected saliva samples.

Main Methods:

• Developed a robotic nucleic acid extraction assay for SARS-CoV-2 RNA in saliva.
• Implemented the assay in the Free Asymptomatic Saliva Testing (IGI FAST) study (11,971 tests).
• Adapted the assay for pooled saliva processing and benchmarked against nasopharyngeal swabs.

Main Results:

• The robotic assay successfully detected rare SARS-CoV-2 positive saliva specimens during low prevalence.
• The assay was adapted for pooled samples, demonstrating potential for increased testing capacity.
• Saliva testing sensitivity requires further optimization to match nasopharyngeal swabs.

Conclusions:

• A robotic extraction-based procedure enables rapid, PCR-based saliva testing for COVID-19.
• The method is suitable for both symptomatic and asymptomatic individuals.
• Further optimization is needed to enhance saliva assay sensitivity compared to nasopharyngeal swabs.