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 theI(2)measure and the chi(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.
