Vaccine Evaluation Unit, UK Health Security Agency, UK.
Manchester Metropolitan University, UK.
Vaccine. 2022 Oct 6;40(42):6042-6047. doi: 10.1016/j.vaccine.2022.08.013. Epub 2022 Sep 8.
Invasive meningococcal disease (IMD) affects approximately 1.2 million people worldwide annually. Prevention of IMD is mostly provided through vaccination; however, no licensed vaccine is currently available to protect against meningococcal serogroup X associated infection. Limited data are available on the natural immunity to Neisseria meningitidis serogroup X within the African sub-Saharan meningitis belt. The objective of the study was to provide an overview of natural immunity to serogroup X within a community in the African meningitis belt prior to the introduction of a pentavalent conjugate vaccine (NmCV-5). Prior to its introduction, a validated assay to assess vaccine efficacy was also required. This study therefore incorporated two objectives: a seroprevalence study to assess natural immunity in serum samples (n = 377) collected from Niger, West Africa in 2012, and the validation of a serogroup X serum bactericidal antibody (SBA) assay. Seroprevalence data obtained found that natural immunity to N. meningitidis serogroup X were present in 52.3% of study participants. The highest putative protective titres (≥8) to serogroup X were seen in age group 5-14 years-old (73.9%) and lowest in ages < 1 year old (0%). The SBA assay was successfully validated for selectivity/specificity, precision/reproducibility, linearity, and stability. This study demonstrated the suitability of the serogroup X SBA assay in clinical trials for future meningococcal conjugate vaccines containing serogroup X polysaccharides.
侵袭性脑膜炎球菌病（IMD）每年影响全球约 120 万人。IMD 的预防主要通过疫苗接种来实现；然而，目前尚无针对脑膜炎奈瑟菌血清群 X 相关感染的许可疫苗。在撒哈拉以南非洲脑膜炎带内，针对脑膜炎奈瑟菌血清群 X 的天然免疫的有限数据。该研究的目的是在引入五价结合疫苗（NmCV-5）之前，提供对非洲脑膜炎带内社区中血清群 X 天然免疫的概述。在引入疫苗之前，还需要一种验证的评估疫苗效力的方法。因此，该研究纳入了两个目标：一项血清流行率研究，评估 2012 年在西非尼日尔采集的血清样本（n=377）中的天然免疫情况，以及对血清群 X 血清杀菌抗体（SBA）检测的验证。获得的血清流行率数据发现，研究参与者中有 52.3%存在针对脑膜炎奈瑟菌血清群 X 的天然免疫力。血清群 X 最高的假定保护滴度（≥8）见于 5-14 岁年龄组（73.9%），而在年龄<1 岁的人群中最低（0%）。SBA 检测成功地验证了选择性/特异性、精密度/重复性、线性和稳定性。这项研究证明了血清群 X SBA 检测在未来含有血清群 X 多糖的脑膜炎球菌结合疫苗临床试验中的适用性。
