ICES, Toronto, ON, Canada.
University of Minnesota School of Public Health, Minneapolis, MN, USA.
Vaccine. 2020 Dec 14;38(52):8351-8356. doi: 10.1016/j.vaccine.2020.11.012. Epub 2020 Nov 19.
Vaccines to prevent meningococcal meningitis in the African meningitis belt include PsACWY, a polysaccharide-only vaccine; and PsA-TT, a polysaccharide-protein conjugate vaccine. Protein-energy undernutrition, a condition where children do not receive enough macro- or micronutrients, is related to increased risk of infectious diseases and poor immune function. Reduced immune function could affect vaccine immunogenicity. We investigated connections between protein-energy undernutrition and vaccine immunogenicity and antibody waning to PsACWY and PsA-TT in children in the African meningitis belt.
This is a secondary analysis of data collected as part of four clinical trials testing the safety and efficacy of PsA-TT in children in Mali, Ghana, and Senegal. We identified whether anthropometric growth indices (low height-for-age, weight-for-height, or weight-for-age Z-score categories) were related to reduced vaccine-elicited antibody (measured with rabbit complement) from pre- to 1 month post-vaccination, in linear regression models. We also identified whether these growth indices were related to increased waning for vaccine-elicited antibody over time, in linear regression models.
A total of 697 children were included in our analysis, of which 350 (50.2%) were female; the mean (SD) age was 1.0 (1.1) years, and 578 (83.0%) received PsA-TT. In linear regression models, no consistent statistical relationship was seen between pre-vaccination anthropometric Z-score categories and vaccine immunogenicity, or decline in antibody over time, for either vaccine, although children with low weight-for-height had a greater decline in antibody from 1 to 6 months post-vaccination.
Our analysis did not find protein-energy undernutrition to be associated with immunogenicity or waning of PsACWY- or PsA-TT-elicited antibody in children living in the African meningitis belt. Future studies should consider measuring antibody titers at additional time points post-vaccination, and for longer periods of time, to determine if the rate of antibody waning over a period of several years is associated with protein-energy undernutrition.
预防非洲脑膜炎带中脑膜炎球菌性脑膜炎的疫苗包括仅含多糖的 PsACWY 疫苗和多糖-蛋白结合疫苗 PsA-TT。蛋白质-能量营养不良是指儿童无法摄入足够的宏量或微量营养素，与传染病风险增加和免疫功能低下有关。免疫功能下降可能会影响疫苗的免疫原性。我们研究了蛋白质-能量营养不良与 PsACWY 和 PsA-TT 疫苗免疫原性和抗体衰减之间的关系，这些关系存在于非洲脑膜炎带的儿童中。
这是对在马里、加纳和塞内加尔进行的四项临床试验中收集的数据进行的二次分析，这些试验旨在测试 PsA-TT 在儿童中的安全性和有效性。我们通过线性回归模型确定了从接种前到接种后 1 个月，儿童的人体测量生长指数（身高年龄 Z 评分、体重身高 Z 评分或体重年龄 Z 评分的低类别）是否与降低疫苗诱导的抗体（用兔补体测量）有关。我们还通过线性回归模型确定了这些生长指数是否与随着时间的推移疫苗诱导的抗体衰减增加有关。
我们的分析共纳入了 697 名儿童，其中 350 名（50.2%）为女性；平均（SD）年龄为 1.0（1.1）岁，578 名（83.0%）接种了 PsA-TT。在线性回归模型中，在接种前的人体测量 Z 评分类别与疫苗免疫原性或两种疫苗的抗体随时间的衰减之间没有一致的统计学关系，尽管体重不足的儿童在接种后 1 至 6 个月期间抗体下降幅度更大。
我们的分析并未发现蛋白质-能量营养不良与生活在非洲脑膜炎带的儿童中 PsACWY 或 PsA-TT 诱导的抗体的免疫原性或衰减有关。未来的研究应考虑在接种疫苗后额外的时间点测量抗体滴度，并在更长的时间内测量，以确定在几年的时间内抗体衰减的速度是否与蛋白质-能量营养不良有关。
