Health Inspectorate, Health Directorate, Luxembourg; Department of Epidemiology, School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, the Netherlands.
Health Inspectorate, Health Directorate, Luxembourg.
Vaccine. 2024 Sep 17;42(22):126011. doi: 10.1016/j.vaccine.2024.05.059. Epub 2024 Jun 1.
Luxembourg experienced major consecutive SARS-CoV-2 infection waves due to Omicron variants during 2022 while having achieved a high vaccination coverage in 2021. We investigated the risk factors associated to severe outcomes (i.e., hospitalisation, deaths) and estimated vaccine effectiveness (VE) as well as the role of immunity conferred by prior infections against severe outcomes in adults.
We linked reported SARS-CoV-2 cases among residents aged ≥ 20 years with vaccination data and SARS-CoV-2 related hospitalisations and deaths. Cases were followed-up until day 14 for COVID-19 related hospital admission and up to day 28 for mortality after a positive test. We analysed the association between the vaccination status and severe forms using proportional Cox regression, adjusting for previous infection, age, sex and nursing homes residency. VE was measured as 1-adjusted hazard ratio of vaccinated vs unvaccinated individuals. The population preventable fraction was computed using the adjusted hazard ratio and the proportion of cases within the vaccination category.
Between December 2021, and March 2023, we recorded 187143 SARS-CoV-2 cases, 1728 (0.93%) hospitalizations and 611 (0.33%) deaths. The risk of severe outcomes increased with age, was higher among men and nursing home residents. Compared to unvaccinated adults, VE against hospitalization was 38.8% (95%CI: 28.1%-47.8%) for a complete primary cycle of vaccination, 62.1% (95%CI: 57.0%-66.7%) for one booster, and 71.6% (95%CI: 66.7%-76.2%) for two booster doses. VE against death was respectively 49.5% (95%CI: 30.8%-63.3%), 69.0% (95%CI: 61.2%-75.3%) and 76.2% (95%CI: 68.4%-82.2%). Previous infection was not associated with lower risk of hospitalisation or mortality. The vaccination lowered mortality by 55.8 % (95%CI: 46.3%-62.8%) and reduced hospital admissions by 49.1% (95%CI: 43.4%-54.4%).
Complete vaccination and booster but not previous infection were protective against hospitalization and death. The vaccination program in Luxembourg led to substantial reductions in SARS-CoV-2-related mortality and hospitalizations at the population level.
卢森堡在 2022 年经历了由奥密克戎变异株引起的重大连续 SARS-CoV-2 感染浪潮，而在 2021 年已经实现了高疫苗接种覆盖率。我们研究了与严重后果（即住院、死亡）相关的危险因素，并估计了疫苗有效性（VE）以及先前感染对成年人严重后果的免疫作用。
我们将报告的年龄≥20 岁居民中的 SARS-CoV-2 病例与疫苗接种数据以及 SARS-CoV-2 相关的住院和死亡情况相关联。对病例进行了 14 天的 COVID-19 相关住院治疗随访，对阳性检测后的 28 天内的死亡情况进行了随访。我们使用比例 Cox 回归分析了接种状态与严重形式之间的关系，调整了先前感染、年龄、性别和养老院居住情况。VE 定义为接种组与未接种组的 1 调整后的风险比。使用调整后的风险比和接种组内病例的比例计算人群可预防分数。
2021 年 12 月至 2023 年 3 月，我们记录了 187143 例 SARS-CoV-2 病例、1728 例（0.93%）住院和 611 例（0.33%）死亡。严重后果的风险随年龄增长而增加，男性和养老院居民的风险更高。与未接种的成年人相比，完全初级疫苗接种周期的住院 VE 为 38.8%（95%CI：28.1%-47.8%），一次加强针的 VE 为 62.1%（95%CI：57.0%-66.7%），两次加强针的 VE 为 71.6%（95%CI：66.7%-76.2%）。死亡的 VE 分别为 49.5%（95%CI：30.8%-63.3%）、69.0%（95%CI：61.2%-75.3%）和 76.2%（95%CI：68.4%-82.2%）。先前的感染与较低的住院或死亡风险无关。疫苗接种降低了 55.8%（95%CI：46.3%-62.8%）的死亡率和 49.1%（95%CI：43.4%-54.4%）的住院率。
完全接种疫苗和加强针而不是先前的感染可以预防住院和死亡。卢森堡的疫苗接种计划在人群层面上大大降低了 SARS-CoV-2 相关的死亡率和住院率。
