Mazagatos Clara, Delgado-Sanz Concepción, Milagro Ana, Liébana-Rodríguez María, Larrauri Amparo
National Centre of Epidemiology, Institute of Health Carlos III, 28029 Madrid, Spain.
CIBER Epidemiología y Salud Pública (CIBERESP), 28029 Madrid, Spain.
Vaccines (Basel). 2023 Jun 17;11(6):1110. doi: 10.3390/vaccines11061110.
Annual influenza vaccination is the main strategy to reduce the burden of seasonal influenza epidemics and is recommended for the elderly in most countries with influenza vaccination strategies, with the main objective of preventing hospitalizations and mortality associated with seasonal influenza in this age group. Studies from different countries have estimated the benefits of seasonal influenza vaccination programs in the elderly, preventing a considerable number of cases, hospitalizations and deaths every year. A study measured the number of medically attended confirmed influenza cases in primary care that are prevented annually by vaccination in the population aged 65 and older in Spain, the Netherlands and Portugal, but estimates of the impact of the national influenza vaccination program in the prevention of severe disease in Spain are lacking. The two objectives of this study were to estimate the burden of severe influenza disease in the Spanish population and to measure the impact of influenza vaccination in the prevention of these outcomes in the population aged 65 years and older. Using influenza surveillance systems put in place before the COVID-19 pandemic, we conducted a retrospective observational study to estimate the burden of hospitalizations and ICU admissions in Spain between 2017-18 and 2019-20, by season and age group. Burden estimates for the 65+ group, combined with vaccine effectiveness (VE) and vaccination coverage (VC) data, were used as input data in an ecological, observational study to estimate the impact of the influenza vaccination program on the elderly. We found a higher burden of severe influenza disease in seasons 2017-18 and 2018-19, with A(H3N2) circulation, and in the youngest and oldest age groups. In those aged 65 and older, we estimated an average of 9900 influenza hospitalizations and 1541 ICU admissions averted by vaccination each year. Seasonal influenza vaccination was able to prevent between 11 and 26% influenza hospitalizations and around 40% ICU admissions in the elderly in the three pre-pandemic seasons. In conclusion, our study complements previous analyses in the primary care setting in Spain and demonstrates the benefits of the annual influenza vaccination program in the prevention of severe influenza disease in the elderly, even in seasons with moderate VE.
年度流感疫苗接种是减轻季节性流感流行负担的主要策略，在大多数实施流感疫苗接种策略的国家，该策略被推荐用于老年人，其主要目标是预防该年龄组与季节性流感相关的住院和死亡。来自不同国家的研究估计了季节性流感疫苗接种计划对老年人的益处，每年可预防大量病例、住院和死亡。一项研究测量了西班牙、荷兰和葡萄牙65岁及以上人群中每年通过疫苗接种预防的初级保健中确诊的流感病例数，但西班牙国家流感疫苗接种计划对预防严重疾病的影响估计尚缺。本研究的两个目的是估计西班牙人群中严重流感疾病的负担，并衡量流感疫苗接种对65岁及以上人群预防这些结果的影响。利用在新冠疫情大流行之前建立的流感监测系统，我们进行了一项回顾性观察研究，以按季节和年龄组估计2017 - 18年至2019 - 20年期间西班牙的住院和重症监护病房（ICU）入院负担。65岁及以上年龄组的负担估计数，结合疫苗效力（VE）和疫苗接种覆盖率（VC）数据，被用作一项生态学观察研究的输入数据，以估计流感疫苗接种计划对老年人的影响。我们发现，在2017 - 18年和2018 - 19年季节，随着A（H3N2）的传播，以及在最年轻和最年长年龄组中，严重流感疾病的负担更高。在65岁及以上人群中，我们估计每年通过疫苗接种可避免平均9900例流感住院和1541例ICU入院。在疫情大流行前的三个季节中，季节性流感疫苗接种能够预防老年人中11%至26%的流感住院和大约40%的ICU入院。总之，我们的研究补充了西班牙初级保健环境中的先前分析，并证明了年度流感疫苗接种计划在预防老年人严重流感疾病方面的益处，即使在疫苗效力中等的季节也是如此。
