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Saliva for molecular detection of SARS-CoV-2 in school-aged children

Our take —

This study examined paired nasopharyngeal (NP) and saliva samples from children aged 3-18 years at community-based screening centers in Dubai, United Arab Emirates in October 2020. Conditions for testing included contact with a confirmed COVID-19 patient, presumptive symptoms, or return to school. Both symptomatic and asymptomatic students were tested. Sensitivity and specificity of saliva samples were 87.7% and 98.5% respectively, compared to RT-PCR tests of the NP samples. This suggests that saliva-based testing may be a valid alternative to NP swab testing in school-age children. However, results did not include breakdowns by age or by symptoms (vs. no symptoms) and may not be generalized to children under 3 years of age.

Study design

Cross-Sectional

Study population and setting

Between October 1 and 23, 2020, 476 population-based children (age 3-18 years) were recruited from Dubai Health Authority community-based screening centers in Dubai, United Arab Emirates. Conditions for testing included contact with confirmed COVID-19 patient, presumptive symptoms, or return to school. Paired saliva and nasopharyngeal (NP) swab samples were taken by a trained healthcare person, and RT-PCR was used for SARS-CoV-2 detection.

Summary of Main Findings

The prevalence of COVID-19 diagnosed by NP swab was 16.7%, and 15.9% by saliva. The sensitivity and specificity of using the saliva sample was 87.7% (95% CI 78.5-93.9) and 98.5% (95% CI 96.8-99.5), respectively. Positive and negative predictive values were 92.2% (95% CI 84.2-96.3) and 97.6% (95%CI 95.7-98.6), respectively. Concordance between NP and saliva was not different by age or gender.

Study Strengths

This was a prospective study where a large cohort of population-based, school-aged children, both symptomatic and asymptomatic were recruited. Comparable results were observed between NP and saliva samples.

Limitations

No further age breakdown was used to determine if saliva testing is useful in younger vs older children, or in those under 3 years old. Likewise, the authors did not report whether NP and saliva concordance were different in asymptomatic vs symptomatic children.

Value added

This study was one of the largest to look at saliva and NP sampling for COVID-19 detection in population-based children (3-18 years).

This review was posted on: 21 May 2021