Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Pfizer, Vaccines Research, Pfizer Inc, Collegeville, Pennsylvania, USA.
Clin Infect Dis. 2021 Feb 1;72(3):448-454. doi: 10.1093/cid/ciaa083.
Pneumococcal conjugate vaccines (PCVs) elicit lower immune response against serotypes carried before or at the time of vaccination (hyporesponsiveness) in infants. The limited studies conducted to date did not permit comprehensive insights regarding this phenomenon. This study, the largest ever conducted with both carriage and serologic endpoints, attempted to add insight on serotype-specific hyporesponsiveness in relation to the number of PCV doses administered before carriage acquisition.
In a double-blind randomized clinical trial (n = 1754 infants), 7-valent or 13-valent PCV was administered at ages 2, 4, 6, and 12 months. New acquisition was defined based on nasopharyngeal swabs at ages 2, 4, 6, 7, and 12 months. Serotype-specific immunoglobulin G levels were obtained 1 month after the infant series and 1 month after the toddler dose.
A lower immune response after the infant series and the toddler dose was consistently observed for carriers of serotypes 6A, 6B, 18C, and 19F at predefined time points, with a similar trend observed in carriers of serotype 23F. In contrast, carriage of serotypes 9V, 14, and 19A did not generally affect immune responses. For some but not all serotypes, hyporesponsiveness was decreased with an increased number of vaccine doses received before acquisition. A complex interrelationship between carriage and immune response was observed between cross-reacting serotypes.
Carrier-induced hyporesponsiveness to PCVs is common, differs among serotypes, and depends on timing of carriage acquisition and prior number of administered PCV doses.
NCT00508742.
肺炎球菌结合疫苗（PCV）在婴儿时期接种前或同时针对携带的血清型产生较低的免疫应答（低反应性）。迄今为止进行的有限研究尚不能全面了解这一现象。本研究是迄今为止针对该现象进行的最大规模的携带和血清学终点研究，旨在深入了解与接种 PCV 剂量数相关的特定血清型低反应性。
在一项双盲随机临床试验（n=1754 名婴儿）中，于 2、4、6 和 12 月龄时分别接种 7 价或 13 价 PCV。根据 2、4、6、7 和 12 月龄时鼻咽拭子的结果来定义新的携带。在婴儿系列接种后 1 个月和幼儿剂量接种后 1 个月获得血清型特异性免疫球蛋白 G 水平。
在预定时间点，6A、6B、18C 和 19F 血清型的携带婴儿在婴儿系列和幼儿剂量后观察到持续较低的免疫反应，23F 血清型的携带婴儿也观察到类似的趋势。相比之下，9V、14 和 19A 血清型的携带通常不会影响免疫反应。对于某些但不是所有的血清型，低反应性随着接种前疫苗剂量数的增加而减少。在交叉反应性血清型之间观察到携带和免疫反应之间存在复杂的相互关系。
载体诱导的 PCV 低反应性很常见，在不同血清型之间存在差异，并且取决于携带的时间和之前接种的 PCV 剂量数。
NCT00508742。
