Severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) is an emerging viral pandemic disease. In the last 6 months, SARS-CoV-2 has caused millions of reported cases and hundreds of thousands of deaths. As other world regions, South America has not contained the pandemic’s advance since it lacks the hospital and economic capacities. Public health implications of transmission, while the asymptomatic/presymptomatic infection is a critical concern at the current pandemic. Describe the socio-demographic, clinical, and viral features of a cohort of SARS-CoV-2 infected individuals from the Colombian Caribbean. Six hundred eighty-six clinical samples of suspected SARS-CoV-2 infection cases and contacts individuals from several hospital centers in the department of Córdoba, Colombia, were received at our laboratory between April 9th and May 16th, 2020. RNA was extracted using lysis buffers and spin columns. The samples were tested for SARS-CoV-2 by reverse transcription real-time polymerase chain reaction (RT-qPCR) using commercially available multiplex real-time PCR assay for simultaneous detection of 3 target genes of SARS-CoV-2 (Allplex™, 2019-nCoV assay, Korea). Viral copies quantification was done using a standard curve constructed from seriated dilutions of a SARS-CoV-2 positive control. Statics descriptive methods were used. Thirty-five nasopharyngeal samples were positive for SARS-CoV-2 infection; the average age was 43 (range, 1–95 years). Seventeen of 35 (49%) of the patients showed symptoms. Most of them had a cough, fever, and odynophagia; three of the patients reported having arthralgia. Only two patients required hospitalization. None of the patients had known co-morbidities. RT-qPCR results show that two of the symptomatic patients had significantly higher RNA copies than the rest. Eighteen of 35 (51%) individuals were asymptomatic, and the average age was 30 (range, 6–61 years). Four asymptomatic individuals showed a higher copy than some symptomatic patients; nonetheless, the average of RNA copies 8.26 × 1010 was lower than the symptomatic. This study shows that asymptomatic patients may develop infections with a high number of RNA copies. Since a considerable percentage of infections may be asymptomatic/presymptomatic, enhanced testing approaches may be needed to detect these persons. Due the occurrence of a large proportion of infections being a result from transmission originated in asymptomatic/presymptomatic individuals, public health interventions in Colombia should be based on two steps: a massive molecular screening, and viral load quantification. Finally, a remarkable issue in our study is the average age of symptomatic and asymptomatic groups (43 and 30 respectively) which may be important because of the economic impact that has been caused by the coronavirus pandemic and may be probably the cause of the reduced lethality observed in the country and the department at the time of this study.

中文翻译：

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哥伦比亚加勒比海地区SARS-CoV-2有症状和无症状人群的流行病学和病毒学特征

严重急性呼吸系统综合症冠状病毒2（SARS-CoV-2）是一种新兴的病毒大流行性疾病。在过去的6个月中，SARS-CoV-2导致了数百万例报告的病例和数十万例死亡。与其他世界地区一样，南美洲由于缺乏医院和经济能力，因此并未遏制大流行的进程。传播对公共卫生的影响，而无症状/症状前感染是当前大流行的关键问题。描述来自哥伦比亚加勒比海的一组SARS-CoV-2感染者的社会人口统计学，临床和病毒特征。我们于4月9日至5月16日在我们的实验室收到了866份可疑SARS-CoV-2感染病例的临床样本，并来自哥伦比亚科尔多瓦省几个医院中心的联络人，2020年。使用裂解缓冲液和旋转柱提取RNA。使用市售的多重实时PCR检测试剂盒同时检测SARS-CoV-2的3个靶基因（Allplex™， 2019-nCoV分析，韩国）。使用由SARS-CoV-2阳性对照的系列稀释液构建的标准曲线对病毒拷贝进行定量。使用了静态描述方法。35份鼻咽样本的SARS-CoV-2感染呈阳性。平均年龄为43岁（范围1–95岁）。35名患者中有17名（49％）出现症状。他们大多数人咳嗽，发烧和吞咽痛。其中三名患者报告患有关节痛。只有两名患者需要住院。没有患者有已知的合并症。RT-qPCR结果显示，两名有症状患者的RNA拷贝明显高于其余患者。35名患者中有18名（51％）无症状，平均年龄为30岁（6-61岁）。有四个无症状的个体比一些有症状的患者表现出更高的复制率。尽管如此，平均RNA拷贝数为8.26×1010，低于有症状的。这项研究表明，无症状患者可能会感染大量RNA副本。由于相当一部分感染可能是无症状/有症状的，因此可能需要增强的检测方法来检测这些人。由于有很大一部分是由无症状/症状前个体传播引起的感染，因此哥伦比亚的公共卫生干预措施应基于两个步骤：大规模的分子筛查和病毒载量定量。最后，在我们的研究中，一个显着的问题是有症状和无症状组的平均年龄（分别为43岁和30岁），这可能很重要，因为冠状病毒大流行已经对经济产生了影响，并且可能是致死率降低的原因在进行这项研究时在国家和部门中观察到。