Background

During the COVID-19 lockdown period from March 17 to May 11, 2020, French authorities in Paris and its suburbs relocated people experiencing recurrent homelessness to emergency shelters, hotels, and large venues. A serological survey was done at some of these locations to assess the COVID-19 exposure prevalence in this group.

Methods

We did a cross-sectional seroprevalence study at food distribution sites, emergency shelters, and workers' residences that were provided medical services by Médecins Sans Frontières in Paris and Seine-Saint-Denis in the Ile-de-France region. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody seropositivity was detected by Luciferase-Linked Immunosorbent Assay and Pseudo Neutralization Test. Sociodemographic and exposure related information was collected via a verbal questionnaire to analyse risk factors and associations with various COVID-19 symptoms.

Findings

Between June 23 and July 2, 2020, 426 (52%) of 818 individuals recruited tested positive in 14 sites. Seroprevalence varied significantly by type of recruitment site (χ² p<0·0001), being highest among those living in workers' residences (88·7%, 95% CI 81·8–93·2), followed by emergency shelters (50·5%, 46·3–54·7), and food distribution sites (27·8%, 20·8–35·7). More than two thirds of COVID-19 seropositive individuals (68%, 95% CI 64·2–72·2; 291 of 426) did not report any symptoms during the recall period. COVID-19 seropositivity was strongly associated with overcrowding (medium density: adjusted odds ratio [aOR] 2·7, 95% CI 1·5–5·1, p=0·0020; high density: aOR 3·4, 1·7–6·9, p<0·0001).

Interpretation

These results show high exposure to SARS-CoV-2 with important variations between those at different study sites. Living in crowded conditions was the strongest factor associated with exposure level. This study underscores the importance of providing safe, uncrowded accommodation, alongside adequate testing and public health information.

Funding

Médecins Sans Frontières, Epicentre, Institut Pasteur's URGENCE nouveau coronavirus fund, Total Foundation.

中文翻译：

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法国巴黎无家可归者的血清阳性率和接触 COVID-19 的危险因素：一项横断面研究

 背景

在2020年3月17日至5月11日的COVID-19封锁期间，巴黎及其郊区的法国当局将经常无家可归的人转移到紧急避难所、酒店和大型场所。在其中一些地点进行了血清学调查，以评估该群体中的 COVID-19 暴露率。

 方法

我们在巴黎无国界医生组织和法兰西岛地区塞纳-圣但尼省提供医疗服务的食品分发点、紧急避难所和工人住所进行了横断面血清流行率研究。通过荧光素酶联免疫吸附测定和伪中和试验检测到严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 抗体血清阳性。通过口头调查问卷收集社会人口统计和暴露相关信息，以分析风险因素以及与各种 COVID-19 症状的关联。

 发现

2020 年 6 月 23 日至 7 月 2 日期间，14 个地点招募的 818 名人员中有 426 名（52%）检测结果呈阳性。血清阳性率因招募地点类型的不同而存在显着差异 (χ ² p<0·0001)，其中居住在工人住所的血清阳性率最高 (88·7%，95% CI 81·8–93·2)，其次是紧急避难所 ( 50·5%, 46·3–54·7), 以及食品分发站 (27·8%, 20·8–35·7)。超过三分之二的 COVID-19 血清阳性个体（68%，95% CI 64·2–72·2；426 人中的 291 人）在召回期间没有报告任何症状。 COVID-19 血清阳性与过度拥挤密切相关（中等密度：调整优势比 [aOR] 2·7，95% CI 1·5–5·1，p=0·0020；高密度：aOR 3·4, 1· 7–6·9，p<0·0001）。

 解释

这些结果表明，不同研究地点的 SARS-CoV-2 暴露程度存在显着差异。生活在拥挤的环境中是与暴露水平相关的最强因素。这项研究强调了提供安全、不拥挤的住宿以及充分的检测和公共卫生信息的重要性。

 资金

无国界医生组织、Epicenter、巴斯德研究所紧急新冠病毒基金、道达尔基金会。