英格兰伦敦的 SARS-CoV-2 感染：2020 年 3 月至 5 月封锁期间社区点患病率的变化。
SARS-CoV-2 infection in London, England: changes to community point prevalence around lockdown time, March-May 2020.
机构信息
National Infection Service, Public Health England, London, UK
National Infection Service, Public Health England, London, UK.
出版信息
J Epidemiol Community Health. 2021 Feb;75(2):185-188. doi: 10.1136/jech-2020-214730. Epub 2020 Oct 1.
BACKGROUND
The UK has been one of the European countries most affected by COVID-19 pandemic. The UK implemented a lockdown in March 2020, when testing policy at the time was focusing on hospitalised cases. Limited information is therefore available on the impact of the lockdown on point prevalence in the community. We assessed COVID-19 point prevalence in London between early April and early May 2020, which approximately reflect infection around the time of the lockdown and 3-5 weeks into lockdown.
METHODS
We tested 1064 participants of a community surveillance cohort for acute COVID-19 infection using PCR in London in April and May 2020 and described positivity as well as characteristics and symptoms of the participants.
RESULTS
Point prevalence decreased from 2.2% (95% CI 1.4 to 3.5) in early April to 0.2% (95% CI 0.03 to 1.6) in early May. 22% of those who tested positive in April were asymptomatic. Extrapolation from reports of confirmed cases suggest that 5-7.6% of total infections were confirmed by testing during this period.
CONCLUSION
COVID-19 point prevalence in the community sharply decreased after lockdown was implemented. This study is based on a small sample and regular seroprevalence studies are needed to better characterise population-level immunity.
背景
英国是受 COVID-19 大流行影响最严重的欧洲国家之一。英国于 2020 年 3 月实施封锁，当时的检测政策侧重于住院病例。因此，关于封锁对社区现患率的影响的信息有限。我们评估了 2020 年 4 月初至 5 月初伦敦的 COVID-19 现患率，这大致反映了封锁前后和封锁后 3-5 周的感染情况。
方法
我们使用 PCR 在伦敦对社区监测队列中的 1064 名参与者进行了急性 COVID-19 感染检测，并描述了阳性率以及参与者的特征和症状。
结果
现患率从 4 月初的 2.2%（95%CI 1.4 至 3.5）降至 5 月初的 0.2%（95%CI 0.03 至 1.6）。4 月份检测呈阳性的人中，有 22%无症状。从确诊病例报告推断，在此期间，通过检测确诊的总感染人数占 5-7.6%。
结论
封锁后，社区的 COVID-19 现患率急剧下降。本研究基于小样本，需要定期进行血清流行率研究，以更好地描述人群水平的免疫力。
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