《自然》雜志今天在線發(fā)表的一篇新冠病毒最新研究論文。來自德國的科研團隊通過對來自慕尼黑的新冠肺炎患者進行詳細病毒學分析，研究了 9 名新冠肺炎確診中青年患者的病毒排出情況。
這些患者呼吸道疾病癥狀相對較輕，在慕尼黑的同一家醫(yī)院接受上呼吸道輕微癥狀的治療。研究人員分析了患者的咽拭子和肺組織標本、痰液（呼吸道分泌的粘液），以及在他們臨床病程中采集的糞便、血液和尿液，發(fā)現(xiàn)新冠病毒在患者上呼吸道的復制較為活躍，說明病毒可能在癥狀出現(xiàn)后的第一周內(nèi)“排毒”水平較高。
隨著癥狀逐漸減輕，研究人員在癥狀出現(xiàn)后的第 8 天依然能從患者的咽拭子和肺組織標本中分離出具有傳染性的毒株。其中兩位有肺炎早期跡象的患者，其痰液在第 10 天或第 11 天時仍持續(xù)有高水平的病毒排出。癥狀消失后，痰液中仍舊可以檢測到病毒 RNA。
研究人員指出，在所分析的患者中新冠病毒與 SARS 病毒展現(xiàn)出了截然不同的病毒學特征。對 SARS 病毒而言，一般在出現(xiàn)癥狀的 7-10 天后，RNA 水平才會達到峰值。而新冠病毒看似“出道即巔峰”，在出現(xiàn)癥狀的 5 天內(nèi)，RNA 水平就達到了峰值。而且相較 SARS 病毒，該峰值可以高出 1000 倍！此外，研究人員在血樣或尿樣中未檢測到病毒，在糞便樣本中也未發(fā)現(xiàn)病毒復制，但能檢測到高濃度的病毒 RNA。這一結果支持病毒或不會通過糞便傳播的理論。
不過，仍需開展樣本量更大的研究，對這一可能傳播途徑做進一步調(diào)查。綜合來看，這些初步結果表明，在患者癥狀還較輕的早期，SARS-CoV-2 在上呼吸道的病毒排出能力也最強。作者認為，后續(xù)研究或有助于評估患者出現(xiàn)癥狀一周后的病毒載量增加是否能預示癥狀的加重。
論文摘要：
Coronavirus disease 2019 (COVID-19) is an acute respiratory tract infection that emerged in late 2019. Initial outbreaks in China involved 13.8% cases with severe, and 6.1% with critical courses. This severe presentation corresponds to the usage of a virus receptor that is expressed predominantly in the lung. By causing an early onset of severe symptoms, this same receptor tropism is thought to have determined pathogenicity, but also aided the control, of severe acute respiratory syndrome (SARS) in 2003. However, there are reports of COVID-19 cases with mild upper respiratory tract symptoms, suggesting the potential for pre- or oligosymptomatic transmission. There is an urgent need for information on body site-specific virus replication, immunity, and infectivity. Here we provide a detailed virological analysis of nine cases, providing proof of active virus replication in upper respiratory tract tissues. Pharyngeal virus shedding was very high during the first week of symptoms. Infectious virus was readily isolated from throat- and lung-derived samples, but not from stool samples, in spite of high virus RNA concentration. Blood and urine never yielded virus. Active replication in the throat was confirmed by viral replicative RNA intermediates in throat samples. Sequence-distinct virus populations were consistently detected in throat and lung samples from the same patient, proving independent replication. Shedding of viral RNA from sputum outlasted the end of symptoms. Seroconversion occurred after 7 days in 50% of patients (14 days in all), but was not followed by a rapid decline in viral load. COVID-19 can present as a mild upper respiratory tract illness. Active virus replication in the upper respiratory tract puts the prospects of COVID-19 containment in perspective.論文全文：
https://www.nature.com/articles/s41586-020-2196-x
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