key: cord-0871821-cchhp8bu authors: Cañete, Martín González; Valenzuela, Isidora Mujica; Garcés, Patricia Carvajal; Massó, Isabel Castro; González, María Julieta; Providell, Sergio González title: Saliva sample for the massive screening of SARS-CoV-2 infection. A Systematic Review date: 2021-02-01 journal: Oral Surg Oral Med Oral Pathol Oral Radiol DOI: 10.1016/j.oooo.2021.01.028 sha: 455cfa4bcdd45645afafd3a997d09951a14b1eec doc_id: 871821 cord_uid: cchhp8bu OBJECTIVES: : This systematic review aims to describe the value of saliva as a non-invasive sample for the detection of SARS-CoV-2, in comparison with the current method for sample collection, the nasopharyngeal swabs. METHODS: : We conducted a systematic review of the literature, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. We searched in 5 databases: PubMed, Cochrane, EBSCO, Elsevier, and MEDLINE, and included articles published between December 2019 and July 2020. RESULTS: : This review included 22 publications that met inclusion criteria, 17 of which were case series, 2 case reports, and 3 massive screenings. All articles compared saliva with nasopharyngeal swabs. The detection rate of SARS-CoV-2 in saliva was similar to NPS. The sensitivity ranged between 20% and 97%, and specificity ranged between 66 and 100%. CONCLUSIONS: : This systematic review found that saliva might be an appropriate, fast, painless, simple, and non-invasive sample for SARS-CoV-2 detection, making it ideal for massive screening of SARS-CoV-2 infection. Since the first outbreak was reported in Wuhan, China, in December 2019, more than 62 million cases of Coronavirus disease 2019 (COVID -19) have been reported until the end of November 2020 1 . More than 1.4 million people have died worldwide, according to WHO statistics 1 . The global pandemic was declared on March 11, 2020 , and since then, government's regulations have been adopted to reduce the transmissibility and many countries declared quarantine, closing their borders 2,3 . Since many regions have not controlled the outbreak to date, regulations are heavily impacting the economy, and incomes have been drastically reduced. These measures have been enforced and maintained in some countries up until now, mainly because mass screening of infected population is not yet available. Thus, traceability remains one of the biggest challenges to control the pandemic, while we wait for the development of a potential vaccine that interrupts the transmission of SARS-CoV-2 4, 5 . Mass screening for SARS-CoV-2 is defined as a high number of tests done in a population, regardless of their status (symptomatic or asymptomatic), in order to identify and quarantine positive cases. 6 According to WHO recommendations, case-tracing and boosting testing capacity should be regarded as the main policy of disease-surveillance, especially when cases begin to drop, or when facing a second wave of infection, in order to rapidly detect and isolate positive cases. These, along with social distancing, are the foundations for a public health-based COVID-19 response 4, 5, 7 . Determining the exact number of asymptomatic or mild cases, which until now seems to be underreported, is the utmost important factor to ensure case-tracing, given that these cases are the ones driving the pandemic. Massive screening or early testing of suspicious asymptomatic cases may help in reducing the transmission, limiting the spread of the disease. For this purpose, rapid diagnostic tests are widely necessary [8] [9] [10] . COVID-19 diagnosis currently requires the obtention of a sample through a nasopharyngeal swab (NPS), that must be performed by medical or trained personal. 11 . In this context, other sources for sample collection have been proposed, including saliva, which offers some advantages in comparison to NPS. Considering that massive screening will be probably adopted for more countries to control the pandemic, we propose that saliva could be a better sample than NPS, because saliva collection can be performed by the patient himself, avoiding the need to attend a health-care facility, thus diminishing crowding and healthcare personal exposure 12 . It has been reported that saliva sample collection is easy, fast, widely accepted by patients, and cost-wise, allowing for massive testing 13, 14 We also screened the references of the selected articles to identify any relevant articles that were not included through the search strategy. Afterward, both authors compared the selected articles and discussed their inclusion for full-text review and final inclusion. All duplicated articles were excluded. All disagreements were settled by discussion between the 2 authors. All articles that did not answer the focused question were excluded. Both authors extracted the relevant data from the selected articles, including first author, year of publication, country, n, sex and age of the included patients, samplecollection method (obtention, storage, and processing), and diagnostic method for SARS-CoV-2 detection. In total, 48 articles were found with the search strategies combining the 5 databases. 40 were selected by screening titles and abstracts. After a discussion between the 2 authors, 34 articles that met the inclusion criteria were included for full-text review. Manual screening was performed for the 34 articles, no new articles were included this way. After full-text review, an agreement was reached by the 2 reviewers to include 22 articles in the current review. The process of article selection is depicted in the flow chart ( Fig. 1 ). Countries h. SARS-CoV-2 detection method: rRT-qPCR. The greatest viral load has been reported in the morning, thus, the sample must be obtained during the first hours of the day to ensure good results 25 . In parallel, the patients must follow instructions before the sample collection, to avoid contamination 12, 17, 21 . World Health Organization (WHO) Effects of policies and containment measures on control of COVID19 epidemic in Chongqing SARS-CoV-2 and Europe: timing of containment measures for outbreak control Effectiveness of isolation, testing, contact tracing, and physical distancing on reducing transmission of SARS-CoV-2 in different settings: a mathematical modelling study COVID-19 pandemic: Understanding the emergence, pathogenesis and containment (Review) Population-wide testing of SARS-CoV-2: country experiences and potential approaches in the EU/EEA and the United Kingdom European Commission request Definition Contact tracing in the context of COVID-19 Impact of contact tracing on SARS-CoV-2 transmission Serology testing in the COVID-19 pandemic response Contact tracing in patients infected with SARS-CoV-2. 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