Validating saliva as a biological sample for cost-effective, rapid and routine screening for SARS-CoV-2

Area of Science:

• Virology
• Public Health
• Molecular Diagnostics

Background:

• Non-invasive saliva samples offer a scalable alternative to nasopharyngeal/oropharyngeal swabs for SARS-CoV-2 detection.
• Routine population screening is crucial for managing the spread of SARS-CoV-2.

Purpose of the Study:

• To investigate the efficacy of saliva samples compared to nasopharyngeal/oropharyngeal swabs (N/OPS-VTM) for RT-PCR based SARS-CoV-2 detection.
• To evaluate the potential of saliva samples for scalable and routine population screening of SARS-CoV-2.

Main Methods:

• Paired nasopharyngeal/oropharyngeal swabs and saliva samples were collected from suspected SARS-CoV-2 positive patients.
• RT-PCR was used to test both sample types.
• Generalized linear models and simulations were employed to analyze result agreement and the effectiveness of saliva-based screening.

Main Results:

• A 75.4% agreement was observed between saliva and N/OPS-VTM, increasing to 83% for samples stored less than three days.
• Saliva samples processed within two days showed 74.5% test sensitivity.
• Simulations indicated that high-capacity testing with 75% sensitivity is effective in limiting infection clusters.

Conclusions:

• Saliva is a viable alternative for SARS-CoV-2 surveillance, particularly when samples are processed immediately.
• Despite slightly lower sensitivity than N/OPS-VTM, saliva's logistical advantages support its use.
• Saliva-based screening is recommended for large workplaces, schools, and population-level surveillance.