Medical Research Council Unit, Banjul, The Gambia.
PLoS One. 2012;7(8):e42997. doi: 10.1371/journal.pone.0042997. Epub 2012 Aug 14.
A recent trial with PCV-7 in a rural Gambian community showed reduced vaccine-type pneumococcal carriage in fully vaccinated compared with control communities. We measured pneumococcal polysaccharide antibody concentrations in this trial to understand further the mechanisms underlying the observed changes.
A single-blind, cluster-randomized (by village) trial was conducted in 21 Gambian villages. In 11 villages, all residents received PCV-7 (Vaccine group); in 10 control villages only children <30 months old or those born during the study received PCV-7. Subjects over the age of 30 months resident in vaccine villages received a single dose of PCV-7 whilst those in control villages received a single dose of a serogroup C meningococcal conjugate vaccine. Serum antibody concentrations against specific pneumococcal polysaccharides were measured in approximately 200 age-stratified subjects before, 4-6, 12 and 24 months following vaccination.
Baseline pneumococcal antibody concentrations were generally high and increased with age up to 10 years. One dose of PCV-7 increased geometric mean antibody concentrations (GMC) in vaccinated versus control villages for vaccine serotypes 6B and 18C, and 4 and 18C, in the young (under 5 years) and older age groups (5+ years) respectively. There were significantly higher proportions of subjects in the vaccinated than in the control communities with an antibody concentration believed to protect against carriage (>5.0 µg/mL) for all but serotype 9V of the PCV-7 serotypes in the older group, but not in the younger age group.
Higher antibodies in vaccinated communities provide an explanation for the lower pneumococcal carriage rates in fully vaccinated compared to control communities.
Controlled-Trials.com ISRCTN51695599 51695599.
最近在冈比亚农村社区进行的一项 PCV-7 试验显示，与对照社区相比，完全接种疫苗的社区中疫苗型肺炎球菌携带率降低。我们在该试验中测量了肺炎球菌多糖抗体浓度，以进一步了解观察到的变化的机制。
在 21 个冈比亚村庄进行了一项单盲、整群随机（按村庄）试验。在 11 个村庄中，所有居民均接种了 PCV-7（疫苗组）；在 10 个对照村庄中，仅 30 个月以下或在研究期间出生的儿童接种了 PCV-7。30 个月以上的疫苗接种村庄居民接种了一剂 PCV-7，而对照村庄居民接种了一剂血清型 C 脑膜炎球菌结合疫苗。接种疫苗前、接种后 4-6、12 和 24 个月，约 200 名按年龄分层的受试者测量了针对特定肺炎球菌多糖的血清抗体浓度。
基线肺炎球菌抗体浓度通常较高，并随年龄增长至 10 岁。一剂 PCV-7 增加了接种疫苗与对照组村庄的疫苗血清型 6B 和 18C 的几何平均抗体浓度（GMC），以及年轻（5 岁以下）和年长（5 岁以上）年龄组的 4 和 18C。与对照组相比，在疫苗接种社区中，具有保护作用的抗体浓度（>5.0 µg/mL）的受试者比例显著更高，除了年长组的 PCV-7 血清型 9V 外，其他所有血清型均如此，但在年轻组中并非如此。
接种疫苗社区中的高抗体水平解释了与对照组相比，完全接种疫苗的社区中肺炎球菌携带率较低的原因。
Controlled-Trials.com ISRCTN51695599（51695599）。
