Saliva is more sensitive for SARS-CoV-2 detection in COVID-19 patients than nasopharyngeal swabs

Anne Louise Wyllie; John Fournier; Arnau Casanovas-Massana; Melissa Campbell; Maria Tokuyama; Pavithra Vijayakumar; Bertie Geng; M. Catherine Muenker; Adam J. Moore; Chantal B. F. Vogels; Mary E. Petrone; Isabel M. Ott; Peiwen Lu; Alice Lu-Culligan; Jonathan Klein; Arvind Venkataraman; Rebecca Earnest; Michael Simonov; Rupak Datta; Ryan Handoko; Nida Naushad; Lorenzo R. Sewanan; Jordan Valdez; Elizabeth B. White; Sarah Lapidus; Chaney C. Kalinich; Xiaodong Jiang; Daniel J. Kim; Eriko Kudo; Melissa Linehan; Tianyang Mao; Miyu Moriyama; Ji Eun Oh; Annsea Park; Julio Silva; Eric Song; Takehiro Takahashi; Manabu Taura; Orr-El Weizman; Patrick Wong; Yexin Yang; Santos Bermejo; Camila Odio; Saad B. Omer; Charles S. Dela Cruz; Shelli Farhadian; Richard A. Martinello; Akiko Iwasaki; Nathan D. Grubaugh; Albert I. Ko

Efforts to control SARS-CoV-2, the novel coronavirus causing COVID-19 pandemic, depend on accurate and rapid diagnostic testing. These tests must be ( 1 ) sensitive to mild and asymptomatic infections to promote effective self isolation and reduce transmission within high risk groups 1 ; ( 2 ) consistent to reliably monitor disease progression and aid clinical decisions 2 ; and ( 3 ) scalable to inform local and national public health policies, such as when social distancing measures can be safely relaxed. However, current SARS-CoV-2 testing strategies often fail to meet these criteria, in part because of their reliance on nasopharyngeal swabs as the widely recommended sample type for real-time RT-PCR. Although nasopharyngeal swabs are commonly used in respiratory virus diagnostics, they show relatively poor sensitivity for SARS-CoV-2 detection in early infection and are inconsistent during serial testing [2] [3] [4] [5] [6] . Moreover, collecting nasopharyngeal swabs causes discomfort to patients due to the procedure's invasiveness, limiting compliance for repeat testing, and presents a considerable risk to healthcare workers, because it can induce patients to sneeze or cough, expelling virus particles 7 . The procedure is also not conducive to large-scale testing, because there are widespread shortages of swabs and personal protective equipment for healthcare workers 8 , and self-collection of nasopharyngeal swabs is difficult and less sensitive for virus detection 9 . These challenges will be further exacerbated as the COVID-19 pandemic intensifies in low income countries. Given the limitations, a more reliable and less resource-intensive sample collection method, ideally one that accommodates self-collection in the home, is urgently needed.