鼻咽拭子检测新冠病毒太痛苦?柳叶刀最新研究提示冠状病毒检测新途径!

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鼻咽拭子和咽拭子采集过程是采集呼吸道标本的一种常见操作,然而侵入性的操作往往会让患者感到明显不适、痛苦,而且采集过程中患者咳嗽、打喷嚏产生的气溶胶还会对医护人员造成潜在的感染风险,为了更好地连续采样并监测病毒载量,研究团队选择让患者在护士的指导下自我收集口咽后部的唾液样本。如果患者接受了插管,则改为采用气道抽取物。另外,研究人员也采集了血液、尿液和肛拭子的样本。

 

研究者从23例患者中一共采集获得173份呼吸道标本。研究人员通过RT-qPCR检测来确定样本中的病毒载量。结果显示,患者呼吸道样本的中位病毒载量为5.2 log10拷贝/mL(四分位距 4.1-7.0),只有3名(13%)患者的唾液样本中未检测出新冠病毒RNA。

 


该研究主要得出了以下两个结论:



患者出现症状后的第一周,唾液病毒载量最高,随后逐渐下降。

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在患者的人口学特征中,年龄增加与病毒载量升高有关。严重患者的初始和峰值病毒载量略高于轻症患者,但差异不显著。有无合并症对初始和峰值病毒载量也没有明显影响。

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原文阅读


Background

Coronavirus disease 2019 (COVID-19) causes severe community and nosocomial outbreaks. Comprehensive data for serial respiratory viral load and serum antibody responses from patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are not yet available. Nasopharyngeal and throat swabs are usually obtained for serial viral load monitoring of respiratory infections but gathering these specimens can cause discomfort for patients and put health-care workers at risk. We aimed to ascertain the serial respiratory viral load of SARS-CoV-2 in posterior oropharyngeal (deep throat) saliva samples from patients with COVID-19, and serum antibody responses.

 

Methods

We did a cohort study at two hospitals in Hong Kong. We included patients with laboratory-confirmed COVID-19. We obtained samples of blood, urine, posterior oropharyngeal saliva, and rectal swabs. Serial viral load was ascertained by reverse transcriptase quantitative PCR (RT-qPCR). Antibody levels against the SARS-CoV-2 internal nucleoprotein (NP) and surface spike protein receptor binding domain (RBD) were measured using EIA. Whole-genome sequencing was done to identify possible mutations arising during infection.

 

Findings

Between Jan 22, 2020, and Feb 12, 2020, 30 patients were screened for inclusion, of whom 23 were included (median age 62 years [range 37–75]). The median viral load in posterior oropharyngeal saliva or other respiratory specimens at presentation was 5·2 log10 copies per mL (IQR 4·1–7·0). Salivary viral load was highest during the first week after symptom onset and subsequently declined with time (slope –0·15, 95% CI –0·19 to –0·11; R²=0·71). In one patient, viral RNA was detected 25 days after symptom onset. Older age was correlated with higher viral load (Spearman’s ρ=0·48, 95% CI 0·074–0·75; p=0·020). For 16 patients with serum samples available 14 days or longer after symptom onset, rates of seropositivity were 94% for anti-NP IgG (n=15), 88% for anti-NP IgM (n=14), 100% for anti-RBD IgG (n=16), and 94% for anti-RBD IgM (n=15). Anti-SARS-CoV-2-NP or anti-SARS-CoV-2-RBD IgG levels correlated with virus neutralisation titre (R²>0·9). No genome mutations were detected on serial samples.

 

Interpretation

Posterior oropharyngeal saliva samples are a non-invasive specimen more acceptable to patients and health-care workers. Unlike severe acute respiratory syndrome, patients with COVID-19 had the highest viral load near presentation, which could account for the fast-spreading nature of this epidemic. This finding emphasises the importance of stringent infection control and early use of potent antiviral agents, alone or in combination, for highrisk individuals. Serological assay can complement RT-qPCR for diagnosis.

 


参考文献


To, K. K.-W., Tsang, O. T.-Y., Leung, W.-S., Tam, A. R., Wu, T.-C., Lung, D. C., … Yuen, K.-Y. (2020). Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study. The Lancet Infectious Diseases. doi:10.1016/s1473-3099(20)30196-1





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