Section of Respiratory Virus, Subdepartment of Viral Diseases, Biomedical Department, Public Health Institute of Chile, Santiago, Chile.
Section of Oncogenic Virus, Subdepartment of Viral Diseases, Biomedical Department, Public Health Institute of Chile, Santiago, Chile.
J Med Virol. 2021 Apr;93(4):2439-2445. doi: 10.1002/jmv.26761. Epub 2021 Jan 5.
Diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) cases is based on the count of real-time reverse transcription-plymerase chain reaction (RT-PCR) positive people. Viral load by real-time RT-PCR has been suggested as a biomarker of the SARS-CoV-2 infection. However, the association of viral load and severity of the disease is not yet resolved. Nasopharyngeal samples from 458 patients were tested by RT-PCR for SARS-CoV-2 diagnosis. Relative quantitation was made by the comparative threshold cycle (ΔΔC ) formula between ORF1ab viral and RNase P housekeeping genes. Absolute viral load was calculate using a reference positive control. Most prevalent clinical signs were cough (75.8%), myalgia (66.7%), and fever (48.5%). Hypertension (18.2%), neurological diseases (15.1%), and asthma and hypothyroidism (12.1%) were most frequent comorbidities. Fever, either as an exclusive symptom or combined with others, was associated with high viral loads ( range, 35.65-155.16; 4.25-4.89 log RNA copies/test]). During the first week after onset of symptoms in mild patients up to 60 years-old was detected the peak of viral load. Children under 10 years old have a high viral load (313.84; 2.50) in the first 2 days postinfection with a sharp decline thereafter. Cases between 10 and 49 years old mostly showed low and moderate viral load during the first 2 days postinfection (range, 0.03 to 17.24; -1.50 to 1.24). Patients over 60 years old have high viral load up to the second week after the onset of symptoms (range, 25.32-155.42; 1.40-2.19), indicating the longer presence of the virus in them. These findings suggest the viral load in nasopharyngeal swabs would help to monitor the SARS-CoV-2 infection in mild coronavirus disease 2019 cases.
严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）病例的诊断基于实时逆转录-聚合酶链反应（RT-PCR）阳性人数。实时 RT-PCR 的病毒载量已被认为是 SARS-CoV-2 感染的生物标志物。然而，病毒载量与疾病严重程度的关系尚未解决。对 458 例患者的鼻咽样本进行 RT-PCR 检测以诊断 SARS-CoV-2。通过 ORF1ab 病毒和 RNase P 管家基因之间的比较阈值循环（ΔΔC）公式进行相对定量。使用参考阳性对照计算绝对病毒载量。最常见的临床症状是咳嗽（75.8%）、肌肉痛（66.7%）和发热（48.5%）。高血压（18.2%）、神经系统疾病（15.1%）和哮喘及甲状腺功能减退症（12.1%）是最常见的合并症。发热（无论是单独出现还是与其他症状同时出现）与高病毒载量相关（范围，35.65-155.16；4.25-4.89 log RNA 拷贝/测试]）。在 60 岁以下轻症患者症状出现后的第一周内检测到病毒载量峰值。10 岁以下儿童感染后前 2 天病毒载量较高（313.84；2.50），此后急剧下降。10-49 岁的病例在感染后前 2 天大多表现出低中和中度病毒载量（范围，0.03-17.24；-1.50-1.24）。60 岁以上的患者在症状出现后的第二周内病毒载量较高（范围，25.32-155.42；1.40-2.19），表明病毒在他们体内存在时间较长。这些发现表明，鼻咽拭子中的病毒载量有助于监测轻症 2019 冠状病毒病患者的 SARS-CoV-2 感染。
