呈指数增长,SARS-CoV-2的高流行率,以及与德尔塔变种相关的疫苗有效性
Paul Elliott1,2,3,4,5,6, David Haw1,7, Haowei Wang1,7
1School of Public Health, Imperial College London, London, UK.
概括
2021年夏季,在英格兰的SARS-CoV-2感染率激增,在年轻,未接种疫苗的人群中患病率更高. 尽管如此,COVID-19疫苗显示出50-60%的抗感染效果.
科学领域:
- 流行病学
- 传染性疾病
- 疫苗学
背景情况:
- 2021 年夏季初,SARS-CoV-2 德尔塔变种的出现导致全球感染率上升.
- 了解传播动态和疫苗的有效性对于公共卫生战略至关重要.
研究的目的:
- 在英格兰的德尔塔变种激增期间评估SARS-CoV-2拭子阳性趋势.
- 评估疫苗接种情况对感染率的影响,并估计疫苗的有效性.
主要方法:
- 在英国实时评估社区传播的数据 (REACT-1).
- 分析了2021年6月至7月的反转录聚合酶链反应 (RT-PCR) 拭子阳性率.
- 接种疫苗和未接种疫苗的人群之间的比较流行率,调整为人口因素.
主要成果:
- 感染持续呈指数增长,平均翻倍时间为25天.
- 德尔塔变异完全取代了阿尔法变异,导致传播增加.
- 与双重接种疫苗的患者相比,未接种疫苗的患者患病率高出三倍 (1. 21% 与 0. 40%).
- 在双接种疫苗的人群中,疫苗对感染的有效性估计在50%至60%之间.
结论:
- 增加的社会混合,加上德尔塔变种的占主导地位,甚至在高度接种疫苗的人群中也促进了感染的增长.
- 疫苗接种显著降低了感染率,但并没有消除传播,这凸显了持续监测和控制措施的必要性.
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