Saliva as a Candidate for COVID-19 Diagnostic Testing: A Meta-Analysis

Abstract

Background: COVID-19 is a serious and potentially deadly disease. Early diagnosis of infected individuals will play an important role in stopping its further escalation. The present gold standard for sampling is the nasopharyngeal swab method. However, several recent papers suggested that saliva-based testing is a promising alternative that could simplify and accelerate COVID-19 diagnosis. Objectives: Our aim was to conduct a meta-analysis on the reliability and consistency of SARS-CoV-2 viral RNA detection in saliva specimens. Methods: We have reported our meta-analysis according to the Cochrane Handbook. We searched the Cochrane Library, Embase, Pubmed, Scopus, Web of Science and clinical trial registries for eligible studies published between 1 January and 25 April 2020. The number of positive tests and the total number of tests conducted were collected as raw data. The proportion of positive tests in the pooled data were calculated by score confidence-interval estimation with the Freeman–Tukey transformation. Heterogeneity was assessed using the I 2 measure and the χ 2 -test. Results: The systematic search revealed 96 records after removal of duplicates. Twenty-six records were included for qualitative analysis and 5 records for quantitative synthesis. We found 91% (CI 80–99%) sensitivity for saliva tests and 98% (CI 89–100%) sensitivity for nasopharyngeal swab (NPS) tests in previously confirmed COVID-19 patients, with moderate heterogeneity among the studies. Additionally, we identified 18 registered, ongoing clinical trials of saliva-based tests for detection of the virus. Conclusion: Saliva tests offer a promising alternative to NPS for COVID-19 diagnosis. However, further diagnostic accuracy studies are needed to improve their specificity and sensitivity.

COVID-19—Lessons Learned and Questions Remaining

“…Patient self-collection of respiratory tract specimens and the use of alternative samples such as mid-turbinate swabs, anterior nasal swabs, throat swabs and saliva may help to alleviate shortages of testing supplies and personal protective equipment [ 177 , 178 ]. Easy-to-collect specimen types such as saliva, being used for the first time in clinical practice, provide convenience and cost advantages for mass screening [ 179 ]. Whether findings with SARS-CoV-2 will generalize to other infectious diseases in the future remains to be determined.…”

Relative Sensitivity of Saliva and Upper Airway Swabs for Initial Detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Ambulatory Patients

“…In spite of these weaknesses, this systematic review has several offsetting strengths. It focuses on sample sets that have been taken at the same time, thus differing from other systematic reviews, 34 , 35 , 36 , 37 , 38 as well as a release from the Norwegian Institute of Public Health. ( https://www.fhi.no/globalassets/dokumenterfiler/rapporter/2020/saliva-sample-for-testing-sars-cov-2-infection-memo-2020.pdf , last accessed 12/14/2020) The total number of samples included in the meta-analysis is substantially greater than that of any idividual study based on simultaneous sample comparison, and allows for meta-analysis based sensitivity estimates.…”

Diagnostyka zakażeń SARS-CoV-2

“…Ponadto, test ze śliny może mieć znaczący wpływ na zwiększenie dostępności badań w kierunku COVID-19 [33]. Metanaliza pięciu badań dotycząca skuteczności i powtarzalności wykrywania wirusowego RNA SARS-CoV-2, do której włączono łącznie 123 pacjentów wykazała 91% czułości testów z próbki śliny i 98% czułości w przypadku wymazów z nosogardła [34]. Badania naukowców z Uniwersytetu Yale wśród 70 pacjentów z COVID-19 wykazały większy odsetek dodatnich testów z próbek śliny niż próbek wymazu z nosogardła.…”