Effectiveness of influenza vaccination on influenza-associated hospitalisations over time among children in Hong Kong: a test-negative case-control study
Effectiveness of influenza vaccination on influenza-associated hospitalisations over time among children in Hong Kong: a test-negative case-control study
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DOI：
10.1016/s2213-2600(18)30419-3
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发表时间：
2018-12-01
影响因子：
76.2
通讯作者：
Cowling, Benjamin J.
中科院分区：
文献类型：
--
作者：
Feng, Shuo;Chiu, Susan S.;Cowling, Benjamin J.
背景流感疫苗的保护作用通常被认为持续不到一年，需要每年重新接种一次。然而，流感疫苗效力在一年中可能下降的速度尚不清楚，这对全年有流感活动的地区特别重要。我们的目的是利用香港流感几乎全年循环的特点，评估流感疫苗在接种疫苗到入院之间的时间间隔如何变化。方法在这项检测阴性的病例对照研究中，我们分析了连续5年(2012-17年)在香港住院的6个月至17岁儿童的疫苗效果。我们纳入了那些在香港四家公立医院住进普通病房的患者，他们发烧(摄氏38度)，并有任何呼吸道症状，如流鼻水、咳嗽或喉咙痛。采用直接免疫荧光法和逆转录-聚合酶链式反应检测流感病毒感染情况，并记录儿童流感免疫史。我们比较了阳性病例和阴性对照的特点，并通过回归分析检验了疫苗效力随接种疫苗到入院时间的变化。结果在2012年9月1日至2017年8月31日期间，我们招募了15 695名因呼吸道感染住院的儿童，其中2500名(15.9%)甲型或乙型流感检测呈阳性，13195例(84.1%)检测为阴性。159例(6.4%)流感阳性病例和1445例(11.0%)流感阴性病例接种过疫苗。大多数疫苗接种是在每个流感疫苗接种季节的12月之前完成的。与流感相关的入院病例常年发生，大多数年份的高峰期在1-3月，2016年夏季高峰期；所有年龄段儿童的联合疫苗有效性在9-12月为79%(95%CI 42-92)，1-4月为67%(57-74)，5-8月为43%(25-57)。对甲型或乙型流感疫苗效力估计为79%(95%CI-88)。接种后5-2个月，60%(46-71)在2-4个月内，57%(39-70)在4-6个月内，45%(22-61)在6-9个月内。在按类型和亚型进行的单独分析中，我们估计疫苗有效性每月下降2-5个百分点。在香港儿童接种疫苗后的9个月内，解释为流感疫苗的有效性下降。我们的发现证实了儿童每年接种疫苗的重要性。需要提供更广泛和更持久保护的流感疫苗，以在流感季节性不规律或流感活动时间较长的地区提供全年保护。版权所有(C)2018爱思唯尔有限公司。保留所有权利。
Background The protection conferred by influenza vaccination is generally thought to last less than a year, necessitating annual revaccination. However, the speed with which influenza vaccine effectiveness might decline during a year is unknown, which is of particular importance for locations with year-round influenza activity. We aimed to assess how influenza vaccine effectiveness changes by time intervals between vaccination and admission to hospital, taking advantage of almost year-round circulation of influenza in Hong Kong.Methods In this test-negative case-control study, we analysed vaccine effectiveness in children (aged 6 months to 17 years) who were admitted to hospital in Hong Kong over 5 consecutive years (2012-17). We included those who were admitted to general wards in four public hospitals in Hong Kong with a fever (>= 38 degrees C) and any respiratory symptom, such as runny nose, cough, or sore throat. We used direct immunofluorescence assay and reverse transcription PCR to detect influenza virus infection, and recorded children's influenza immunisation history. We compared characteristics of positive cases and negative controls and examined how vaccine effectiveness changed by time between vaccination and admission to hospital with regression analyses.Findings Between Sept 1, 2012, and Aug 31, 2017, we enrolled 15 695 children hospitalised for respiratory infections, including 2500 (15.9%) who tested positive for influenza A or B and 13 195 (84.1%) who tested negative. 159 (6.4%) influenza-positive cases and 1445 (11.0%) influenza-negative cases had been vaccinated. Most vaccinations were done by December of each influenza vaccination season. Influenza-related admissions to hospital occurred year-round, with peaks in January through March in most years and a large summer peak in 2016; pooled vaccine effectiveness for children of all ages was 79% (95% CI 42-92) for September to December, 67% (57-74) for January to April, and 43% (25-57) for May to August. Vaccine effectiveness against influenza A or B was estimated as 79% (95% CI 64-88) within 0 . 5-2 months of vaccination, 60% (46-71) within > 2-4 months, 57% (39-70) within > 4-6 months, and 45% (22-61) within > 6-9 months. In separate analyses by type and subtype, we estimated that vaccine effectiveness declined by 2-5 percentage points per month.Interpretation Influenza vaccine effectiveness decreased during the 9 months after vaccination in children in Hong Kong. Our findings confirm the importance of annual vaccination in children. Influenza vaccines that provide broader and longer-lasting protection are needed to provide year-round protection in regions with irregular influenza seasonality or lengthy periods of influenza activity.Copyright (C) 2018 Elsevier Ltd. All rights reserved.