Coverage and timeliness of vaccination and the validity of routine estimates: Insights from a vaccine registry in Kenya
Coverage and timeliness of vaccination and the validity of routine estimates: Insights from a vaccine registry in Kenya
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DOI：
10.1016/j.vaccine.2018.11.005
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发表时间：
2018-12-18
期刊：
影响因子：
5.5
通讯作者：
Scott, J. Anthony G.
中科院分区：
文献类型：
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作者：
Adetifa, Ifedayo M. O.;Karia, Boniface;Scott, J. Anthony G.
背景：儿童疫苗的益处主要取决于疫苗接种覆盖率。我们使用了疫苗注册表（作为黄金标准），以量化常规覆盖方法中的误差（调查和行政报告），以估计幸存者偏见的程度，对比覆盖率与及时性，并使用这两种措施来估计人口免疫力。肯尼亚基利菲卫生和人口监测系统（KHDSS）的儿童疫苗接种记录与出生、死亡、2010年至2017年的移民和居住数据。使用逆生存曲线，我们估计了最新和年龄适当的疫苗接种覆盖率，计算了婴儿期的平均疫苗接种覆盖率作为逆生存曲线下的面积，并估计了完全免疫儿童（FIC）的比例。结果与公布的覆盖率估计进行了比较。接种疫苗的风险因素进行了评估，使用考克斯回归models.Results：我们分析了49,090名婴儿和48,025名儿童年龄12-23个月的6个出生队列和6个横断面调查的数据，发现第二年的生活调查高估了2%的覆盖率相比，出生队列。与婴儿的平均覆盖率相比，口服脊髓灰质炎五价疫苗（Penta 3）和肺炎球菌结合疫苗第三剂在12个月时的静态覆盖率被夸大了7-8%，麻疹疫苗被夸大了24%。调查和行政覆盖也低估了10- 14%的完全免疫儿童的比例。对于卡介苗，Penta 3和麻疹，及时性是23-44%，在卫生设施出生的儿童，但20-37%，在那些谁第一次参加在疫苗stockouts.Conclusions：标准覆盖率调查12-23个月大的儿童高估保护忽视及时性，幸存者和回忆偏见。在延迟接种疫苗很常见的地方，最新的覆盖率将对人群免疫力做出有偏差的估计。调查和行政方法也低估了FIC的流行率。为了控制疫苗可预防的疾病，需要更好地衡量覆盖率和进行更复杂的分析。(C)2018作者（S）爱思唯尔有限公司出版
Background: The benefits of childhood vaccines are critically dependent on vaccination coverage. We used a vaccine registry (as gold standard) in Kenya to quantify errors in routine coverage methods (surveys and administrative reports), to estimate the magnitude of survivor bias, contrast coverage with timeliness and use both measures to estimate population immunity.Methods: Vaccination records of children in the Kilifi Health and Demographic Surveillance System (KHDSS), Kenya were combined with births, deaths, migration and residence data from 2010 to 17. Using inverse survival curves, we estimated up-to-date and age-appropriate vaccination coverage, calculated mean vaccination coverage in infancy as the area under the inverse survival curves, and estimated the proportion of fully immunised children (FIC). Results were compared with published coverage estimates. Risk factors for vaccination were assessed using Cox regression models.Results: We analysed data for 49,090 infants and 48,025 children aged 12-23 months in 6 birth cohorts and 6 cross-sectional surveys respectively, and found 2nd year of life surveys overestimated coverage by 2% compared to birth cohorts. Compared to mean coverage in infants, static coverage at 12 months was exaggerated by 7-8% for third doses of oral polio, pentavalent (Penta3) and pneumococcal conjugate vaccines, and by 24% for the measles vaccine. Surveys and administrative coverage also underestimated the proportion of the fully immunised child by 10-14%. For BCG, Penta3 and measles, timeliness was 23-44% higher in children born in a health facility but 20-37% lower in those who first attended during vaccine stock outs.Conclusions: Standard coverage surveys in 12-23 month old children overestimate protection by ignoring timeliness, and survivor and recall biases. Where delayed vaccination is common, up-to-date coverage will give biased estimates of population immunity. Surveys and administrative methods also underestimate FIC prevalence. Better measurement of coverage and more sophisticated analyses are required to control vaccine preventable diseases. (C) 2018 The Author(s). Published by Elsevier Ltd.