學(xué)術(shù)分享

什么是病毒突變株？

病毒在進行復(fù)制時，其遺傳物質(zhì)會發(fā)生變化，這些變化被稱為“突變”。而具有一個或多個新突變的病毒被稱為原始病毒的“變體”（即突變株）。新冠病毒作為一種分子穩(wěn)定性相對較差的RNA病毒，發(fā)生突變是再正常不過的一件事情，目前全球已經(jīng)發(fā)現(xiàn)了數(shù)百種新冠病毒的變體，其中大部分對新冠病毒的屬性影響很小甚至無影響，我們真正需要關(guān)注的是那些會影響病毒屬性的突變株。

新冠病毒的“有效”突變株主要從兩方面來影響病毒的屬性：

1）增強新冠病毒與宿主蛋白ACE2受體的親和力，從而增強病毒的感染能力；

2）幫助新冠病毒逃逸宿主免疫系統(tǒng)的攻擊，導(dǎo)致人類二次感染概率升高甚至降低疫苗有效性。

目前，尚無證據(jù)表明已知的突變點會增強新冠病毒的致病性（人感染后病情加重）。

五種重要的突變株

莫慌！核酸檢測依然靠譜

新型冠狀病毒肺炎疫情爆發(fā)以來，新冠病毒核酸檢測已經(jīng)成為群眾日常生活中司空見慣的場景，甚至在2021年的春節(jié)，一張核酸檢測陰性報告成為了大家回鄉(xiāng)的“車票”。當(dāng)下，越來越多新冠病毒突變株的出現(xiàn)引起了人們對于新冠核酸檢測有效性的擔(dān)憂。莫慌，筆者這就給大家排解焦慮~

依據(jù)國家新冠診療方案的要求，國內(nèi)主流的新冠檢測試劑靶標多為ORF1ab基因和N基因，而目前發(fā)現(xiàn)的新冠突變株的“有效”突變點基本集中在S蛋白上，對于檢測的有效性不會造成顯著影響。此外，伯杰醫(yī)療目前亦已完成對現(xiàn)有試劑引物探針與突變株的核對，結(jié)果證實：伯杰醫(yī)療已經(jīng)上市的新型冠狀病毒2019-nCoV核酸檢測試劑盒（熒光PCR法），針對最新突變株均不會出現(xiàn)脫靶和漏檢，仍可保證檢測試劑的準確性和靈敏性。

如何快速鑒別新冠突變株？

截至目前，全球已知的新冠病毒變體高達數(shù)百種，其中引人關(guān)注的B.1.1.7突變株、B.1.351突變株和P.1突變株存在的免疫逃逸現(xiàn)象已經(jīng)引起廣泛關(guān)注和討論，隱患依然存在。因而，世衛(wèi)組織及國際專家依然在密切監(jiān)測新冠病毒的變化，以便能及時發(fā)現(xiàn)重大突變，國內(nèi)也仍需投入巨大的精力監(jiān)測新冠突變株的流行情況。看來，對于這些突變株，不該省的工序還是不能省~

當(dāng)下，全球?qū)π鹿谕蛔冎辏ㄓ绕涫俏粗蛔冎辏┑谋O(jiān)測，主要依賴基因測序技術(shù)以及全球科研人員對測序結(jié)果數(shù)據(jù)的共享。但基因測序的時間往往較長，在情況緊急時，及時響應(yīng)成了一個大問題。因而，對于已知有特異性突變點的突變株，我們也可以通過熒光PCR技術(shù)對突變株進行快速鑒別分型和溯源監(jiān)測，避免貽誤疫情防控。

參考文獻

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