Afonso Yolanda Pires, Bejko Dritan, Ernst Corinna, Huberty Conny, Wienecke-Baldacchino Anke, Berger Sibel, Herold Malte, Walczak Cécile, Ogorzaly Leslie, Vergison Anne, Mossong Joël
Health Directorate, Luxembourg, Luxembourg.
Department of Microbiology, National Health Laboratory, Dudelange, Luxembourg.
Sci Rep. 2025 Mar 25;15(1):10293. doi: 10.1038/s41598-025-94323-4.
In summer 2021, while the Delta variant was predominant in many European countries, Luxembourg experienced a large outbreak of the P.1.17.1 SARS-CoV-2 Gamma variant. This surge coincided with the introduction of digital COVID-19 certificates and eased restrictions prior to national holiday festivities. We investigated the molecular and epidemiological factors contributing to SARS-CoV-2 Gamma transmission. All laboratory SARS-CoV-2 confirmed cases were interviewed by contact tracing teams on exposures at nightlife venues, family gatherings, schools, and workplaces. Gamma sublineages were investigated through environmental wastewater surveillance, in addition to whole genome sequencing of clinical data. Infection clusters were analysed combining phylogenetic with epidemiological exposures. From June 22 to August 12, 2021, we identified 1,049 cases of the Gamma P.1.17.1 sublineage, representing 39.2% of all sequenced cases. Initially, nightlife was the most frequent source setting (49.1%) with young adults accounting for 92.3% of these cases. Later, transmission shifted towards family (30.4%) setting with a corresponding increase in the age distribution. The C26645T mutation in the M-protein was associated with attending specific nightclub venues. Notably, 96.8% of cases were in unvaccinated individuals, and while P.1.17.1 was also detected in neighboring countries, 75.6% of the sequences submitted to GISAID were from Luxembourg. The study suggests the role of nightlife and low population immunity in driving the summer surge of SARS-CoV-2 among young adults, with digital certificates showing minimal impact on transmission. Sequencing of clinical and wastewater samples in combination with contact tracing was crucial to inform the outbreak investigation.
2021年夏季，当许多欧洲国家Delta变种占主导地位时，卢森堡经历了P.1.17.1新冠病毒Gamma变种的大规模暴发。此次激增恰逢数字新冠病毒证书的引入以及在国庆节日庆祝活动前限制措施的放松。我们调查了导致新冠病毒Gamma变种传播的分子和流行病学因素。所有实验室确诊的新冠病毒病例均由接触者追踪团队就其在夜生活场所、家庭聚会、学校和工作场所的暴露情况进行询问。除了对临床数据进行全基因组测序外，还通过环境废水监测对Gamma亚谱系进行了调查。结合系统发育和流行病学暴露情况对感染簇进行分析。2021年6月22日至8月12日，我们共确定了1049例Gamma P.1.17.1亚谱系病例，占所有测序病例的39.2%。最初，夜生活场所是最常见的感染源（49.1%），这些病例中92.3%为年轻人。后来，传播转向家庭（30.4%），年龄分布相应增加。M蛋白中的C26645T突变与前往特定夜总会场所有关。值得注意的是，96.8%的病例为未接种疫苗者，虽然邻国也检测到了P.1.17.1，但提交给全球流感共享数据库（GISAID）的序列中有75.6%来自卢森堡。该研究表明，夜生活和低人群免疫力在推动年轻人中新冠病毒夏季激增方面发挥了作用，数字证书对传播的影响微乎其微。临床和废水样本测序与接触者追踪相结合对于疫情调查至关重要。
