Williams I T, Milton J D, Farrell J B, Graham N M
Department of Epidemiology, Johns Hopkins University, School of Hygiene and Public Health, Baltimore, MD, USA.
Pediatrics. 1995 Sep;96(3 Pt 1):439-46.
To describe the pattern of immunization in the cohort of children who entered public schools in Virginia in 1992.
This was a historic cohort study using stratified cluster sampling. Three strata were created based on the socioeconomic status (SES) of the children in the catchment area of each public school in Virginia.
The random sample included public elementary schools throughout Virginia.
Immunization records were obtained for a randomly selected cohort of 2519 first-grade children in Virginia.
Age at completion of recommended childhood vaccines was determined from birth to school entry by SES, race, and population density. Provider practices were assessed by ascertaining missed opportunities for simultaneous administration of vaccinations according to recommended schedules.
Although immunization completion rates were high at school entry, low levels of immunization coverage were found in all areas of Virginia at 24 months of age regardless of SES (as measured by per capita income), population density, or race. However, under-immunization was more severe for poor children in urban areas (42.3% of children in low-SES urban areas were age-appropriately immunized at 24 months of age versus 64.0% in children in high-SES rural areas). By multivariate logistic regression, race and gender were not predictors of which children were appropriately immunized at 2 years of age after adjusting for the following: SES, population density, receiving the first DTP (diphtheria, tetanus, and pertussis) or OPV (oral polio) vaccination after 3 months of age, and failure to have the first DTP administered simultaneously with the first OPV or the second DTP administered simultaneously with the second OPV. Receiving the first DTP or OPV vaccination after 3 months of age and failure to have the first and second DTP and OPV administered simultaneously were the strongest predictors of not being age-appropriately immunized at 2 years of age. The effect of failure to vaccinate simultaneously on predicting vaccination coverage at 2 years of age was strongly modified by SES. Children who attended schools located in census tracts with per capita incomes less than $10,600 and who did not have the first and second doses of DTP and OPV administered simultaneously were 33.19 times more likely not to be age-appropriately immunized at 2 years of age compared with children who attended schools located in census tracts with per capita incomes greater than $18,800 and who received the first and second doses of DTP and OPV simultaneously (95% confidence interval: 18.29 to 60.22).
Although beginning the immunization schedule at the recommended age was crucial to appropriate vaccination later in life, provider practices were important predictors of under-immunization. Failure to administer vaccinations simultaneously strongly influenced poorer children in Virginia. Serious delays in vaccine administration were observed not only for poor children in urban areas, but also in all areas of Virginia before school entry.
描述1992年进入弗吉尼亚州公立学校的儿童队列中的免疫模式。
这是一项采用分层整群抽样的历史性队列研究。根据弗吉尼亚州各公立学校集水区内儿童的社会经济地位（SES）创建了三个层次。
随机样本包括弗吉尼亚州的公立小学。
获取了弗吉尼亚州随机抽取的2519名一年级儿童队列的免疫记录。
根据SES、种族和人口密度确定从出生到入学时完成推荐的儿童疫苗接种的年龄。通过确定按照推荐时间表同时接种疫苗的错失机会来评估医疗服务提供者的做法。
尽管入学时免疫完成率较高，但无论SES（以人均收入衡量）、人口密度或种族如何，弗吉尼亚州所有地区在24个月龄时的免疫覆盖率都较低。然而，城市地区贫困儿童的免疫不足情况更为严重（低收入城市地区42.3%的儿童在24个月龄时按年龄适当接种了疫苗，而高收入农村地区为64.0%）。通过多因素逻辑回归分析，在调整以下因素后，种族和性别不是2岁时哪些儿童得到适当免疫的预测因素：SES、人口密度、3个月龄后接种第一剂百白破（白喉、破伤风和百日咳）或口服脊髓灰质炎疫苗（OPV），以及第一剂百白破未与第一剂OPV同时接种或第二剂百白破未与第二剂OPV同时接种。3个月龄后接种第一剂百白破或OPV以及第一剂和第二剂百白破与OPV未同时接种是2岁时未按年龄适当免疫的最强预测因素。未同时接种疫苗对预测2岁时疫苗接种覆盖率的影响在很大程度上受到SES的影响。与就读于人均收入高于18,800美元的普查区且同时接种了第一剂和第二剂百白破与OPV的儿童相比，就读于人均收入低于10,600美元的普查区且未同时接种第一剂和第二剂百白破与OPV的儿童在2岁时未按年龄适当免疫的可能性高33.19倍（95%置信区间：18.29至60.22）。
尽管在推荐年龄开始免疫接种计划对日后的适当接种至关重要，但医疗服务提供者的做法是免疫不足的重要预测因素。未同时接种疫苗对弗吉尼亚州较贫困儿童有很大影响。不仅在城市地区的贫困儿童中，而且在弗吉尼亚州所有地区入学前都观察到疫苗接种严重延迟。
