Grant Rebecca, Charmet Tiffany, Schaeffer Laura, Galmiche Simon, Madec Yoann, Von Platen Cassandre, Chény Olivia, Omar Faïza, David Christophe, Rogoff Alexandra, Paireau Juliette, Cauchemez Simon, Carrat Fabrice, Septfons Alexandra, Levy-Bruhl Daniel, Mailles Alexandra, Fontanet Arnaud
Institut Pasteur, Université de Paris, Emerging Diseases Epidemiology Unit, F-75015 Paris, France.
Sorbonne University, Paris, France.
Lancet Reg Health Eur. 2022 Feb;13:100278. doi: 10.1016/j.lanepe.2021.100278. Epub 2021 Nov 26.
We aimed to assess the settings and activities associated with SARS-CoV-2 infection in the context of B.1.617.2 (Delta) variant circulation in France, as well as the protection against symptomatic Delta infection.
In this nationwide case-control study, cases were SARS-CoV-2 infected adults recruited between 23 May and 13 August 2021. Controls were non-infected adults from a national representative panel matched to cases by age, sex, region, population density and calendar week. Participants completed an online questionnaire and multivariable logistic regression analysis was used to determine the association between acute SARS-CoV-2 infection and recent activity-related exposures, past history of SARS-CoV-2 infection, and COVID-19 vaccination.
We did not find any differences in the settings and activities associated with Delta versus non-Delta infections and grouped them for subsequent analyses. In multivariable analysis involving 12634 cases (8644 Delta and 3990 non-Delta) and 5560 controls, we found individuals under 40 years and attending bars (aOR:1.9; 95%CI:1.6-2.2) or parties (aOR:3.4; 95%CI:2.8-4.2) to be at increased risk of infection. In those aged 40 years and older, having children attend daycare (aOR:1.9; 95%CI:1.1-3.3), kindergarten (aOR:1.6; 95%CI:1.2-2.1), primary school (aOR:1.4; 95%CI:1.2-1.6) or middle school (aOR:1.3; 95%CI:1.2-1.6) were associated with increased risk of infection. We found strong protection against symptomatic Delta infection for those with prior infection whether it was recent (2-6 months) (95%; 95%CI:90-97) or associated with one dose (85%; 95%CI:78-90) or two doses of mRNA vaccine (96%; 95%CI:87-99). For those without past infection, protection was lower with two doses of mRNA vaccine (67%; 95%CI:63-71).
In line with other observational studies, we find reduced vaccine effectiveness against symptomatic Delta infections. The settings and activities at increased risk of infection indicate where efforts to reinforce individual and public health measures need to be concentrated.
我们旨在评估在法国B.1.617.2（德尔塔）变种传播背景下与严重急性呼吸综合征冠状病毒2（SARS-CoV-2）感染相关的环境和活动，以及针对有症状的德尔塔感染的防护情况。
在这项全国性病例对照研究中，病例为2021年5月23日至8月13日期间招募的感染SARS-CoV-2的成年人。对照为来自全国代表性样本的未感染成年人，按年龄、性别、地区、人口密度和日历周与病例匹配。参与者完成一份在线问卷，并采用多变量逻辑回归分析来确定急性SARS-CoV-2感染与近期与活动相关的暴露、SARS-CoV-2感染既往史以及新冠病毒疫苗接种之间的关联。
我们未发现与德尔塔感染和非德尔塔感染相关的环境和活动存在任何差异，并将它们合并进行后续分析。在涉及12634例病例（8644例德尔塔感染和3990例非德尔塔感染）和5560名对照的多变量分析中，我们发现40岁以下且去过酒吧（调整后比值比：1.9；95%置信区间：1.6 - 2.2）或参加派对（调整后比值比：3.4；95%置信区间：2.8 - 4.2）的个体感染风险增加。在40岁及以上人群中，孩子参加日托（调整后比值比：1.9；95%置信区间：1.1 - 3.3）、幼儿园（调整后比值比：1.6；95%置信区间：1.2 - 2.1）、小学（调整后比值比：1.4；95%置信区间：1.2 - 1.6）或中学（调整后比值比：1.3；95%置信区间：1.2 - 1.6）与感染风险增加相关。我们发现，无论既往感染是近期（2 - 6个月）（95%；95%置信区间：90 - 97），还是与一剂（85%；95%置信区间：78 - 90）或两剂信使核糖核酸（mRNA）疫苗相关，既往感染过的人对有症状的德尔塔感染都有很强的防护作用。对于没有既往感染的人，两剂mRNA疫苗的防护作用较低（67%；95%置信区间：63 - 71）。
与其他观察性研究一致，我们发现针对有症状的德尔塔感染，疫苗效力有所降低。感染风险增加的环境和活动表明了加强个人和公共卫生措施的努力应集中在哪些方面。
