Background Invasive pneumococcal disease (IPD) leads to thousands of pediatric deaths annually. Pneumococcal colonization precedes IPD. In 2013, the Dominican Republic introduced the 13-valent pneumococcal conjugate vaccine (PCV13) into its routine infant immunization program, with doses at ages 2, 4, and 12 months. Prevalence of pneumococcal nasopharyngeal colonization was evaluated post–PCV13 introduction. Methods A prospective cohort study of 125 children aged 2–35 months was conducted in a rural Dominican Republic community November 2016 through July 2017. Nasopharyngeal swabs and clinical and vaccination data were collected at enrollment and 4–6 months later. Serotypes included in PCV13 were defined as vaccine-type. Colonization rates and serotype distribution were compared at baseline and follow-up, and the association between colonization and vaccination status among the entire cohort was evaluated at each time point. Results Of 125 children enrolled, 118 (94%) completed follow-up. Overall and vaccine-type pneumococcal colonization rates were 62% and 25%, respectively, at baseline and 60% and 28% at follow-up. Among children age-eligible for 3 doses, 50% and 51% were fully vaccinated at baseline and follow-up, respectively. At baseline assessment, children up-to-date for age for PCV13 were less likely to be colonized with vaccine-type pneumococci than children not up-to-date, and the same was found for fully vaccinated children (3 doses) compared to those not fully vaccinated (odds ratios [ORs], 0.38 [95% confidence interval {CI}, .18–.79], and 0.14 [95% CI, .04–.45], respectively). The same associations were not found at follow-up assessment. Conclusions Three years post -PCV13 introduction, vaccine-type colonization rates remained high. Low vaccination coverage for 3 PCV13 doses may have contributed. The protective effect of PCV13 on vaccine-type carriage suggests an increase in PCV13 coverage could lead to substantial declines in pneumococcal vaccine-type carriage.

中文翻译：

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13 价肺炎球菌结合疫苗对多米尼加共和国农村社区肺炎链球菌鼻咽携带率的影响

背景 侵袭性肺炎球菌病 (IPD) 每年导致数千名儿童死亡。肺炎球菌定植先于 IPD。2013 年，多米尼加共和国将 13 价肺炎球菌结合疫苗 (PCV13) 引入其常规婴儿免疫计划，分别在 2、4 和 12 个月大时接种。在 PCV13 引入后评估了肺炎球菌鼻咽定植的患病率。方法 2016 年 11 月至 2017 年 7 月在多米尼加共和国农村社区对 125 名 2-35 个月的儿童进行前瞻性队列研究。在入组时和 4-6 个月后收集鼻咽拭子、临床和疫苗接种数据。PCV13 中包含的血清型被定义为疫苗型。在基线和随访时比较定植率和血清型分布，并且在每个时间点评估了整个队列中定植和疫苗接种状态之间的关联。结果 入组的 125 名儿童中，118 名 (94%) 完成了随访。基线时总体和疫苗型肺炎球菌定植率分别为 62% 和 25%，随访时分别为 60% 和 28%。在符合 3 剂接种条件的儿童中，分别有 50% 和 51% 在基线和随访时完全接种了疫苗。在基线评估中，与未接种疫苗的儿童相比，接种 PCV13 的最新年龄儿童感染疫苗型肺炎球菌的可能性较小，与接种疫苗的儿童（3 剂）相比，接种疫苗的儿童也同样如此。未完全接种疫苗（优势比 [ORs]，分别为 0.38 [95% 置信区间 {CI}，0.18–.79] 和 0.14 [95% CI，0.04–.45]）。在后续评估中未发现相同的关联。结论 PCV13 引入三年后，疫苗型定植率仍然很高。3 剂 PCV13 的低疫苗接种覆盖率可能是原因之一。PCV13 对疫苗型携带的保护作用表明，PCV13 覆盖率的增加可能导致肺炎球菌疫苗型携带的大幅下降。