Ortiz de Lejarazu-Leonardo Raul, Montomoli Emanuele, Wojcik Radek, Christopher Solomon, Mosnier Anne, Pariani Elena, Trilla Garcia Antoni, Fickenscher Helmut, Gärtner Barbara C, Jandhyala Ravi, Zambon Maria, Moore Catherine
Valladolid National Influenza Centre, Calle Rondilla de Santa Teresa s/n, 47009 Valladolid, Spain.
Department of Molecular Medicine, University of Siena, 53100 Siena, Italy.
Vaccines (Basel). 2021 Oct 29;9(11):1255. doi: 10.3390/vaccines9111255.
Influenza vaccines are the main tool to prevent morbidity and mortality of the disease; however, egg adaptations associated with the choice of the manufacturing process may reduce their effectiveness. This study aimed to estimate the impact of egg adaptations and antigenic drift on the effectiveness of trivalent (TIV) and quadrivalent (QIV) influenza vaccines.
Nine experts in influenza virology were recruited into a Delphi-style exercise. In the first round, the experts were asked to answer questions on the impact of antigenic drift and egg adaptations on vaccine match (VM) and influenza vaccine effectiveness (IVE). In the second round, the experts were presented with the data from a systematic literature review on the same subject and aggregated experts' responses to round one questions. The experts were asked to review and confirm or amend their responses before the final summary statistics were calculated.
The experts estimated that, across Europe, the egg adaptations reduce, on average, VM to circulating viruses by 7-21% and reduce IVE by 4-16%. According to the experts, antigenic drift results in a similar impact on VM (8-24%) and IVE (5-20%). The highest reduction in IVE was estimated for the influenza virus A(H3N2) subtype for the under 65 age group. When asked about the frequency of the phenomena, the experts indicated that, on average, between the 2014 and 19 seasons, egg adaptation and antigenic drift were significant enough to impact IVE that occurred in two and three out of five seasons, respectively. They also agreed that this pattern is likely to reoccur in future seasons.
Expert estimates suggest there is a potential for 9% on average (weighted average of "All strains" over three age groups adjusted by population size) and up to a 16% increase in IVE (against A(H3N2), the <65 age group) if egg adaptations that arise when employing the traditional egg-based manufacturing process are avoided.
流感疫苗是预防该疾病发病和死亡的主要工具；然而，与生产工艺选择相关的鸡蛋适应性变化可能会降低其有效性。本研究旨在评估鸡蛋适应性变化和抗原漂移对三价（TIV）和四价（QIV）流感疫苗有效性的影响。
招募了九位流感病毒学专家参与德尔菲法练习。在第一轮中，要求专家回答关于抗原漂移和鸡蛋适应性变化对疫苗匹配度（VM）和流感疫苗有效性（IVE）影响的问题。在第二轮中，向专家展示了关于同一主题的系统文献综述数据，并汇总了专家对第一轮问题的回答。在计算最终汇总统计数据之前，要求专家审查并确认或修改他们的回答。
专家估计，在整个欧洲，鸡蛋适应性变化平均使与流行病毒的疫苗匹配度降低7 - 21%，并使流感疫苗有效性降低4 - 16%。据专家称，抗原漂移对疫苗匹配度（8 - 24%）和流感疫苗有效性（5 - 20%）有类似影响。估计65岁以下年龄组的甲型（H3N2）流感病毒亚型的流感疫苗有效性下降幅度最大。当被问及这些现象的发生频率时，专家表示，平均而言，在2014年至19季期间，鸡蛋适应性变化和抗原漂移分别在五季中的两季和三季中显著到足以影响流感疫苗有效性。他们还一致认为这种模式可能会在未来季节再次出现。
专家估计表明，如果避免采用传统基于鸡蛋的生产工艺时出现的鸡蛋适应性变化，平均有9%的可能性（按人口规模调整的三个年龄组“所有毒株”的加权平均值），并且流感疫苗有效性（针对65岁以下年龄组的甲型（H3N2））最多可提高16%。
