2013年全国以乡为单位适龄儿童国家免疫规划疫苗接种率调查的抽样设计

Sampling Design of the China Immunization Coverage Survey for National Immunization Program Vaccines at the Township Level in 2013

目的研究2013年全国以乡[镇、街道、苏木、新疆生产建设兵团(新疆兵团)团场,下同]为单位适龄儿童国家免疫规划疫苗(National Immunization Program Vaccines,NIPV)接种率调查抽样设计的内容和方法。方法在文献研究和专家咨询的基础上,确定应用批质量保证抽样(Lot Quality Assurance Sampling,LQAS)方法评估以乡为单位适龄儿童NIPV接种率≥90%目标的实施进展情况。县(区、市、旗、新疆兵团师,下同)级以乡为单位儿童NIPV接种率调查辖区所有的乡,省(自治区、直辖市、新疆兵团,下同)级以乡为单位儿童NIPV接种率调查和国家级复核NIPV接种率调查结果均采用系统随机抽样确定调查乡。县、省、国家调查均应用LQAS方法结合多阶段系统随机抽样方法确定调查儿童。结果为评估乡适龄儿童NIPV接种率是否≥90%,每个乡应调查适龄儿童≥42名,其中出现≤1名某剂NIPV未接种儿童,则判定该乡该剂NIPV接种率≥90%;否则,判定为<90%。全国县级以乡为单位NIPV接种率自查,共调查36 549个乡(占全国乡数>90%)、1 536 675名儿童(占全国目标儿童总数约5%)。全国所有省以乡为单位NIPV接种率抽样调查,共调查1073个乡、45 095名适龄儿童,抽取的适龄儿童分年龄、性别构成与2010年全国人口普查构成相似。结论本次调查是自1996年"全国以乡为单位儿童免疫接种率达到85%目标审评"以来,最大规模的、全国性评估以乡为单位儿童NIPV接种率调查,样本代表性较好。LQAS方法的顺利实施对于各级真实掌握以乡为单位NIPV接种率提供了有力的技术支撑。

Objective To evaluate the sampling design and its use in the 2013 China immunization cover- age survey for National Immunization Program vaccines （NIPV） at the township level. Methods On the basis of literature review and experts consultation, lot quality assurance sampling （LQAS） was selected as the sampling method to determine whether the immunization coverage of eligible children attained the national goal of ≥90%. All townships were eligible for county-level self - evaluation. Multistage system- atic random sampling was used for township selection at the provincial level evaluation and national level re-evaluation. LQAS was used for township-level sample size determination, and target children were sampled randomly. Results To determine whether NIPV coverage for a township was ≥ 90%, ≥42 children per township must be sampled, and households interviewed. If ≤1 child was found unimmu-nized for a NIPV at a township, the NIPV immunization coverage of the township was classified as ≥90%; if more than 1 child was found unvaccinated, the township was classified as having ≤90% coverage for NIPV. From a total of 1,536,675 children in 36,549 townships, 45, 095 children from 1,073 townships comprised thestudy sample for household interviews, which were conducted by all counties and provinces. The age and gender composition in the provincial survey was similar to the 2010 census. Conclusions The national immunization coverage survey for NIPV in 2013 was the largest national survey conducted at the township level since the 1996 survey that was used to determine whether NIPV coverage was at least 85%. The samples were representative. LQAS methodology provided an effective methodology for assessing immunization coverage at the township level.