Division of Epidemiology and Community Health, School of Public Health, University of Minnesotagrid.17635.36, Minneapolis, Minnesota, USA.
BioTechnology Institute, College of Biological Sciences, University of Minnesotagrid.17635.36, Saint Paul, Minnesota, USA.
Microbiol Spectr. 2021 Sep 3;9(1):e0008621. doi: 10.1128/Spectrum.00086-21. Epub 2021 Jul 14.
Although nasopharyngeal samples have been considered the gold standard for COVID-19 testing, variability in viral load across different anatomical sites could cause nasopharyngeal samples to be less sensitive than saliva or nasal samples in certain cases. Self-collected samples have logistical advantages over nasopharyngeal samples, making them amenable to population-scale screening. To evaluate sampling alternatives for population screening, we collected nasopharyngeal, saliva, and nasal samples from two cohorts with varied levels and types of symptoms. In a mixed cohort of 60 symptomatic and asymptomatic participants, we found that saliva had 88% concordance with nasopharyngeal samples when tested in the same testing lab ( = 41) and 68% concordance when tested in different testing labs ( = 19). In a second cohort of 20 participants hospitalized for COVID-19, saliva had 74% concordance with nasopharyngeal samples tested in the same testing lab but detected virus in two participants that tested negative with nasopharyngeal samples on the same day. Medical record review showed that the saliva-based testing sensitivity was related to the timing of symptom onset and disease stage. We find that no sample site will be perfectly sensitive for COVID-19 testing in all situations, and the significance of negative results will always need to be determined in the context of clinical signs and symptoms. Saliva retained high clinical sensitivity for early-stage and presymptomatic COVID-19 while allowing easier collection, minimizing the exposure of health care workers, and need for personal protective equipment and making it a viable option for population-scale testing. Methods for COVID-19 detection are necessary for public health efforts to monitor the spread of disease. Nasopharyngeal samples have been considered the best approach for COVID-19 testing. However, alternative samples like self-collected saliva offer advantages for population-scale screening. Meta-analyses of recent studies suggest that saliva is useful for detecting SARS-CoV-2; however, differences in disease prevalence, sample collection, and analysis methods still confound strong conclusions on the utility of saliva compared to nasopharyngeal samples. Here, we find that the sensitivity of saliva testing is related to both the timing of the sample collection relative to symptom onset and the disease stage. Importantly, several clinical vignettes in our cohorts highlight the challenges of medical decision making with limited knowledge of the associations between laboratory test data and the natural biology of infection.
尽管鼻咽拭子已被认为是 COVID-19 检测的金标准，但不同解剖部位的病毒载量的变化可能导致在某些情况下鼻咽拭子的敏感性不如唾液或鼻腔样本。与鼻咽拭子相比，自我采集的样本具有后勤优势，使其适合于人群筛查。为了评估人群筛查的采样替代方案，我们从两个具有不同症状水平和类型的队列中采集了鼻咽、唾液和鼻腔样本。在一个包含 60 名有症状和无症状参与者的混合队列中，我们发现当在同一检测实验室（ = 41）中检测时，唾液与鼻咽样本的一致性为 88%，而当在不同的检测实验室（ = 19）中检测时，一致性为 68%。在第二个队列中，20 名因 COVID-19 住院的参与者中，唾液与在同一检测实验室检测的鼻咽样本的一致性为 74%，但在同一天，鼻咽样本检测为阴性的两名参与者中检测到了病毒。病历回顾显示，基于唾液的检测敏感性与症状发作和疾病阶段有关。我们发现，在所有情况下，没有一种样本部位对 COVID-19 检测都是完全敏感的，阴性结果的意义始终需要结合临床症状和体征来确定。唾液在 COVID-19 的早期和症状前阶段保留了较高的临床敏感性，同时允许更容易地采集，最大程度地减少了医护人员的暴露，减少了对个人防护设备的需求，使其成为人群筛查的可行选择。COVID-19 的检测方法对于公共卫生努力监测疾病的传播是必要的。鼻咽拭子一直被认为是 COVID-19 检测的最佳方法。然而，像自我采集的唾液等替代样本对于人群筛查具有优势。最近的研究的荟萃分析表明，唾液对于检测 SARS-CoV-2 是有用的；然而，由于疾病流行率、样本采集和分析方法的差异，仍然难以得出与鼻咽样本相比唾液的实用性的有力结论。在这里，我们发现唾液检测的敏感性与样本采集相对于症状发作的时间以及疾病阶段有关。重要的是，我们的两个队列中的几个临床病例说明了在有限地了解实验室检测数据与感染的自然生物学之间的关联的情况下，进行医疗决策的挑战。
