WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong Special Administrative Region, China.
Clin Infect Dis. 2024 Oct 15;79(4):901-909. doi: 10.1093/cid/ciae380.
Studies have reported that repeated annual vaccination may influence influenza vaccination effectiveness in the current season.
We established a 5-year randomized placebo-controlled trial of repeated influenza vaccination (Flublok; Sanofi Pasteur) in adults 18-45 years of age. In the first 2 years, participants were randomized to receive vaccine or saline placebo as follows: placebo-placebo (P-P), placebo-vaccine (P-V), or vaccine-vaccine (V-V). Serum samples were collected each year just before vaccination and after 30 and 182 days. A subset of serum samples collected at 5 time points from 95 participants were tested for antibodies against vaccine strains.
From 23 October 2020 through 11 March 2021 we enrolled and randomized 447 adults. Among vaccinated individuals, antibody titers increased between days 0 and 30 against each of the vaccine strains, with smaller increases for repeat vaccinees who on average had higher prevaccination titers in year 2. There were statistically significant differences in the proportions of participants achieving ≥4-fold rises in antibody titer for the repeat vaccinees for influenza A(H1N1), B/Victoria, and B/Yamagata, but not for A(H3N2). Among participants who received vaccination in year 2, there were no significant differences between the P-V and V-V groups in geometric mean titers at day 30 or the proportions of participants with antibody titers ≥40 at day 30 for any of the vaccine strains.
In the first 2 years, during which influenza did not circulate, repeat and first-time vaccinees had similar postvaccination geometric mean titers to all 4 vaccine strains, indicative of similar levels of clinical protection. Clinical Trials Registration. NCT04576377.
研究报告称，反复接种年度流感疫苗可能会影响当前季节的流感疫苗效果。
我们建立了一项为期 5 年的成年人（18-45 岁）重复接种流感疫苗（Flublok；赛诺菲巴斯德）的随机安慰剂对照试验。在前 2 年中，参与者按如下方式随机接受疫苗或盐水安慰剂：安慰剂-安慰剂（P-P）、安慰剂-疫苗（P-V）或疫苗-疫苗（V-V）。每年在接种疫苗前和接种后 30 天和 182 天采集血清样本。从 95 名参与者的 5 个时间点采集的一部分血清样本用于检测针对疫苗株的抗体。
从 2020 年 10 月 23 日至 2021 年 3 月 11 日，我们招募并随机分配了 447 名成年人。在接种疫苗的个体中，针对每种疫苗株的抗体滴度在第 0 天至第 30 天之间增加，而在第二年重复接种疫苗的个体中增加较小，这些个体的平均预接种滴度较高。对于重复接种疫苗的个体，针对 A(H1N1)、B/Victoria 和 B/Yamagata 的流感，抗体滴度增加≥4 倍的参与者比例存在统计学显著差异，但针对 A(H3N2)则没有。在第二年接受疫苗接种的参与者中，P-V 和 V-V 组在第 30 天的几何平均滴度或任何疫苗株第 30 天抗体滴度≥40 的参与者比例均无显著差异。
在前 2 年期间，流感未流行，重复和初次接种疫苗的个体对所有 4 种疫苗株的接种后几何平均滴度相似，表明具有相似水平的临床保护作用。临床试验注册。NCT04576377。
