SARS-CoV-2 B.1.617.2 デルタ変種の複製と免疫回避
Petra Mlcochova1,2, Steven A Kemp1,2,3, Mahesh Shanker Dhar4
1Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Cambridge, UK.
Nature
|September 6, 2021
まとめ
重症急性呼吸器症候群コロナウイルス2型 (SARS-CoV-2) デルタ型は,中和抗体に対する感受性が低下し,ワクチンの有効性が損なわれています. この高度に伝染性の高い変種を管理するために,ワクチン接種後でも感染制御対策を継続することが不可欠です.
科学分野:
- ウイルス学
- 免疫学
- 流行病学について
背景:
- SARS-CoV-2のB.1.617.2 (デルタ) 変種はインドで発生し,アルファやカッパのような以前の株に勝った.
- デルタ変種は,以前のSARS-CoV-2系統と比較して,伝染性および免疫回避性の増加を示しています.
研究 の 目的:
- デルタ変異体の無害化抗体に対する感受性および複製効率を含む in vitro 特徴を評価する.
- デルタ変種に対するワクチンの有効性を実際の医療環境で評価する.
主な方法:
- 回復した個人およびワクチン接種者からの抗体による中和を評価するために,擬似型ウイルスを用いてin vitro測定を行う.
- デルタと他の変種間の複製効率を比較するために,オルガノイドとヒトの呼吸道上皮モデル.
- 混合血統の循環期間中に感染した医療従事者におけるワクチンの有効性の分析
主要な成果:
- デルタ変種は,野生型と比較して,回復した個人およびワクチン接種者の中和抗体に対する敏感性が著しく低下したことを示した.
- デルタは,他の変種よりも高い複製効率とより効率的なシンチウム形成を示した.
- 分析では,非デルタ型と比較して,デルタ型に対するChAdOx1ワクチンの有効性が低下していることが示された.
結論:
- デルタ変異の免疫回避と増殖が,その優位性に寄与している.
- デルタ変種に対するワクチンの有効性の低下は,継続的な感染対策の必要性を強調しています.
- ワクチンの有効性や公衆衛生戦略に対するデルタ変異の感染の影響を完全に理解するためには,さらなる研究が必要である.
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