Saliva testing for the Masses
COSACO Lab Presents a guest lecture by Anne Wylie from Yale University on cost effective and scalable SARS-CoV 2 testing.
Rapid and accurate SARS-CoV-2 diagnostic testing is essential for controlling the ongoing COVID-19 pandemic. The current gold standard for COVID-19 diagnosis is real-time RT-PCR detection of SARSCoV-2 from nasopharyngeal swabs. Low sensitivity, exposure risks to healthcare workers, and global shortages of swabs and personal protective equipment, however, necessitate the validation of new diagnostic approaches. Saliva is a promising candidate for SARS-CoV-2 diagnostics because (1) collection is minimally invasive and can reliably be self-administered and (2) saliva has exhibited comparable sensitivity to nasopharyngeal swabs in detection of other respiratory pathogens, including endemic human coronaviruses, in previous studies.
To validate the use of saliva for SARS-CoV-2 detection, we tested nasopharyngeal and saliva samples from confirmed COVID-19 patients and self-collected samples from healthcare workers on COVID-19 wards. When we compared SARS-CoV-2 detection from patient-matched samples, we found that the sensitivity of virus detection was 88% from saliva and 76% from nasopharyngeal swabs. From temporal collections from the same patient, we found a 7% false negative rate from saliva and a 14% false negative rate from nasopharyngeal swabs. Furthermore, we observed significantly less variability in self-collection of saliva.
Taken together, our findings demonstrate that saliva is a viable and more sensitive alternative to nasopharyngeal swabs and could enable at-home self-administered sample collection for accurate large-scale SARS-CoV-2 testing. SARS-CoV-2 testing from saliva could prove transformative as it can be easily adapted for a range of settings: from workplace to underserved populations.
Please join us as we discuss these findings during our live transmission, scheduled for June 25th, 2020 at 7 PM, via the Ciencia Puerto Rico FaceBook page. (fb.me/cienciapr)