Improved oral detection is a characteristic of Omicron infection and has implications for clinical sampling and tissue tropism

A fast, ultrasensitive SERS immunoassay to detect SARS-CoV-2 in saliva

“…Emergence of the omicron variant, with a change in tissue tropism, precipitated the need for altered testing regimes. As compared to earlier VOCs, the omicron variant replicated rapidly in human nasal cells, albeit at lower titres than were eventually found in lung cells [ [16] , [17] , [18] , [19] ]. Omicron-infected patients have shorter incubation periods prior to symptom onset, and pre-symptomatic viral shedding in saliva has been observed in the absence of nasal shedding [ 20 , 21 ], suggesting an advantage to early viral detection in saliva.…”

Omicron Wave SARS-CoV-2 Diagnosis: Evaluation of Saliva, Anterior Nasal, and Nasopharyngeal Swab Samples

“…While many studies have evaluated the sensitivity of saliva and nasal swab specimens for detecting SARS-CoV-2 at the beginning of the pandemic ( 6 – 9 ), very few have reevaluated their performance since the emergence of the new SARS-CoV-2 variants ( 15 ), especially the Omicron variant ( 16 , 17 ). Our prospective study provides further evidence of the high performance of SARS-CoV-2 diagnosis on saliva samples during the Omicron wave and highlights the higher capacity of saliva samples than of nasopharyngeal and nasal swab samples to detect Omicron variants at an early stage of infection.…”

“…This variant is more transmissible ( 11 ) and has a greater immune escape capacity ( 12 , 13 ) and a less severe outcome ( 14 ) than earlier variants. While some have stressed the importance of reevaluating the suitability of different specimens for diagnosing new variants ( 15 ), the sensitivity of saliva and ANs samples for detecting the Omicron variant has not been thoroughly examined ( 16 , 17 ). One recent study suggested that saliva samples were more suitable for detecting the Omicron variant than the Delta variant ( 17 ).…”

“…While some have stressed the importance of reevaluating the suitability of different specimens for diagnosing new variants ( 15 ), the sensitivity of saliva and ANs samples for detecting the Omicron variant has not been thoroughly examined ( 16 , 17 ). One recent study suggested that saliva samples were more suitable for detecting the Omicron variant than the Delta variant ( 17 ). Ex vivo studies have also demonstrated that the Omicron variant replicates more efficiently in bronchial tissue than in lungs.…”

Clinical performance of SARS-CoV-2 detection on the cobas Liat using water gargle samples

“…This is consistent with ONPS samples being more sensitive in detecting low viral loads compared to SWG samples, at least for certain SARS-CoV-2 variants. Interestingly, some [ 13 , 14 ], but not all [15] studies report increased sensitivity for the detection of Omicron variant in saliva samples. While our study was performed when most circulating strains were of the Alpha lineage, we believe that limiting false negatives especially in a population with high pre-test probability is of utmost importance to help curtail the spread of SARS-CoV-2 infection.…”