Comparison between Saliva and Nasopharyngeal Swabs for the Rapid Detection of Respiratory Viruses Using the Roche...

We evaluated the performance of saliva compared with nasopharyngeal (NP) swabs for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A/B, and respiratory syncytial virus (RSV) using the Roche cobas® Liat® point-of-care platform (Roche, Basel, Switzerland). Within an existing adult cohort in Guatemala, consenting participants with influenza-like illness (ILI) provided paired saliva and NP swabs, which were tested for SARS-CoV-2, influenza A/B, and RSV on the Liat platform. Among 138 ILI episodes from 123 enrolled subjects, 35/124 (28.2%), 5/135 (3.7%), 6/135 (4.4%), and 7/135 (5.2%) samples were reverse transcription polymerase chain reaction-positive for SARS-CoV-2, influenza A, influenza B, and RSV, respectively. For SARS-CoV-2, saliva/NP agreement was 90.3% (Cohen's kappa = 0.731); 12 (9.7%) of the samples were discordant (three saliva-positive only, nine NP-positive only); and the median cycle threshold (Ct) for saliva was higher than that for NP (26.53 versus 23.54; P = 0.005). In our setting, saliva had a lower viral load correlate (Ct) but maintained a good correlation with NP swabs for the detection of SARS-CoV-2 on the Liat platform.