Background

The standard for SARS-CoV-2 diagnosis is RT-PCR from nasopharyngeal or oropharyngeal swabs. Major airports require COVID-19 screening, and saliva has the potential as a substitute specimen for SARS-CoV-2 diagnosis. We investigated the utility of fresh drooled saliva against NPS for COVID-19 screening of travelers.

Methods

We recruited 81 travelers and 15 non-travelers (including ten controls) prospectively within a mean of 3·22 days of RT-PCR confirmed COVID-19. Each study participant provided 2 mls of early morning fresh drooled whole saliva separately into a sterile plastic container and GeneFiX™ saliva collection kit. The saliva specimens were processed within 4 h and tested for SARS-CoV-2 genes (E, RdRP, and N2) and the results compared to paired NPS RT-PCR for diagnostic accuracy.

Results

Majority of travellers were asymptomatic (75·0%) with a mean age of 34·26 years. 77 travelers were RT-PCR positive at the time of hospitalization whilst three travelers had positive contacts. In this group, the detection rate for SARS-CoV-2 with NPS, whole saliva, and GeneFiX™ were comparable (89·3%, 50/56; 87·8%, 43/49; 89·6%, 43/48). Both saliva collection methods were in good agreement (Kappa = 0·69). There was no statistical difference between the detection rates of saliva and NPS (p > 0·05). Detection was highest for the N2 gene whilst the E gene provided the highest viral load (mean = 27·96 to 30·10, SD = 3·14 to 3·85). Saliva specimens have high sensitivity (80·4%) and specificity (90·0%) with a high positive predictive value of 91·8% for SARS-CoV-2 diagnosis.

Conclusion

Saliva for SARS-CoV-2 screening is a simple accurate technique comparable with NPS RT-PCR.

中文翻译：

---

旅行者新鲜流口水对 SARS-CoV-2 的诊断准确性

背景

SARS-CoV-2 的诊断标准是鼻咽或口咽拭子的 RT-PCR。主要机场需要进行 COVID-19 筛查，唾液有可能作为 SARS-CoV-2 诊断的替代标本。我们调查了新鲜流口水对抗 NPS 对旅行者进行 COVID-19 筛查的效用。

方法

我们在 RT-PCR 确认 COVID-19 的平均 3·22 天内前瞻性地招募了 81 名旅行者和 15 名非旅行者（包括 10 名对照组）。每个研究参与者将 2 毫升清晨新鲜流下的全唾液分别放入无菌塑料容器和 GeneFiX™ 唾液收集套件中。唾液标本在 4 小时内处理并测试 SARS-CoV-2 基因（E、RdRP 和 N2），并将结果与​​配对 NPS RT-PCR 进行比较以提高诊断准确性。

结果

大多数旅行者没有症状 (75·0%)，平均年龄为 34·26 岁。77 名旅行者在住院时 RT-PCR 呈阳性，而 3 名旅行者有阳性接触者。在该组中，NPS、全唾液和 GeneFiX™ 对 SARS-CoV-2 的检出率相当（89·3%，50/56；87·8%，43/49；89·6%，43/ 48). 两种唾液收集方法非常一致 (Kappa = 0·69)。唾液检出率与NPS检出率无统计学差异(p > 0·05)。N2 基因的检测最高，而 E 基因的病毒载量最高（平均值 = 27·96 至 30·10，SD = 3·14 至 3·85）。唾液标本具有高灵敏度（80·4%）和特异性（90·0%），对 SARS-CoV-2 诊断的阳性预测值为 91·8%。

结论

用于 SARS-CoV-2 筛查的唾液是一种与 NPS RT-PCR 相当的简单准确的技术。