BACKGROUND Children with chronic medical conditions are at higher risk of invasive pneumococcal disease (IPD), but little is known about the effectiveness of the primary course of pneumococcal conjugate vaccine (PCV) in these children. METHODS A cohort born in 2001-2004 from two Australian states and identified as medically at-risk (MAR) of IPD either using ICD-coded hospitalizations (with conditions of interest identified by 6 months of age) or linked perinatal data (for prematurity) were followed to age 5 years for notified IPD by serotype. We categorized fully vaccinated children as either receiving PCV dose 3 by <12 months of age or ≥1 PCV dose at ≥12 months of age. Cox proportional hazard modeling was used to estimate hazard ratios (HRs), adjusted for confounders, and vaccine effectiveness (VE) was estimated as (1-HR) × 100. RESULTS A total of 9220 children with MAR conditions had 53 episodes of IPD (43 vaccine-type); 4457 (48.3%) were unvaccinated and 4246 (46.1%) were fully vaccinated, with 1371 (32.3%) receiving dose 3 by 12 months and 2875 (67.7%) having ≥1 dose at ≥12 months. Estimated VE in fully vaccinated children was 85.9% (95% CI: 33.9-97.0) against vaccine-type IPD and 71.5% (95% CI: 26.6-88.9) against all-cause IPD. CONCLUSION This is the first population-based study evaluating the effectiveness of PCV in children with MAR conditions using record linkage. Our study provides evidence that the VE for vaccine-type and all-cause IPD in MAR children in Australia is high and not statistically different from previously reported estimates for the general population. This method can be replicated in other countries to evaluate VE in MAR children.

中文翻译：

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7 价肺炎球菌结合疫苗对澳大利亚有医学风险的儿童的侵袭性肺炎球菌疾病的有效性：一项创纪录的关联研究。

背景 患有慢性疾病的儿童患侵袭性肺炎球菌病 (IPD) 的风险较高，但对这些儿童肺炎球菌结合疫苗 (PCV) 初级疗程的有效性知之甚少。方法 2001-2004 年出生于澳大利亚两个州的队列，使用 ICD 编码的住院治疗（6 个月大时确定感兴趣的条件）或关联的围产期数据（早产）确定为 IPD 的医学风险 (MAR)随访至 5 岁，按血清型通知 IPD。我们将完全接种疫苗的儿童分类为在 <12 月龄时接种 3 剂 PCV 或在 ≥12 月龄时接种 ≥1 剂 PCV。Cox比例风险模型用于估计风险比（HRs），调整混杂因素，疫苗有效性（VE）估计为（1-HR）×100。结果 共有 9220 名患有 MAR 疾病的儿童发生了 53 次 IPD（43 种疫苗类型）；4457 人（48.3%）未接种疫苗，4246 人（46.1%）完全接种疫苗，1371 人（32.3%）在 12 个月时接受第 3 剂，2875 人（67.7%）在 ≥12 个月时接种 ≥1 剂。在完全接种疫苗的儿童中，针对疫苗型 IPD 的估计 VE 为 85.9%（95% CI：33.9-97.0），针对全因 IPD 的估计 VE 为 71.5%（95% CI：26.6-88.9）。结论 这是第一个基于人群的研究，使用记录关联评估 PCV 在患有 MAR 疾病的儿童中的有效性。我们的研究提供的证据表明，澳大利亚 MAR 儿童的疫苗类型和全因 IPD 的 VE 很高，并且与之前报道的一般人群估计值没有统计学差异。这种方法可以在其他国家复制，以评估 MAR 儿童的 VE。