ICAP at Columbia University, New York, NY.
U.S. Centers for Disease Control and Prevention, Atlanta, GA.
J Acquir Immune Defic Syndr. 2021 Aug 1;87(Suppl 1):S43-S51. doi: 10.1097/QAI.0000000000002704.
Measurement of mother-to-child HIV transmission through population-based surveys requires large sample sizes because of low HIV prevalence among children. We estimate potential improvements in sampling efficiency resulting from a targeted sample design.
Eight countries in sub-Saharan Africa with completed Population-based HIV Impact Assessment (PHIA) surveys as of 2017.
The PHIA surveys used a geographically stratified 2-stage sample design with households sampled from randomly selected census enumeration areas. Children (0-14 years of age) were eligible for HIV testing within a random subsample of households (usually 50%). Estimates of child HIV prevalence in each country were calculated using jackknife replicate weights. We compared sample sizes and precision achieved using this design with a 2-phase disproportionate sample design applied to strata defined by maternal HIV status and mortality.
HIV prevalence among children ranged from 0.4% (95% confidence interval: 0.2 to 0.6) in Tanzania to 2.8% (95% confidence interval: 2.2 to 3.4) in Eswatini with achieved relative standard errors between 11% and 21%. The expected precision improved in the targeted design in all countries included in the analysis, with proportionate reductions in mean squared error ranging from 27% in Eswatini to 61% in Tanzania, assuming an equal sample size.
Population-based surveys of adult HIV prevalence that also measure child HIV prevalence should consider targeted sampling of children to reduce required sample size, increase precision, and increase the number of positive children tested. The findings from the PHIA surveys can be used as baseline data for informing future sample designs.
由于儿童中 HIV 的患病率较低，因此通过基于人群的调查来衡量母婴 HIV 传播需要大量样本。我们估计有针对性的抽样设计会提高抽样效率。
截至 2017 年，撒哈拉以南非洲的 8 个国家已完成基于人群的 HIV 影响评估（PHIA）调查。
PHIA 调查采用地理分层两阶段抽样设计，从随机选择的人口普查计数区抽取家庭作为样本。在家庭的随机子样本（通常为 50%）内，有资格对儿童（0-14 岁）进行 HIV 检测。使用 Jackknife 重复权重计算每个国家儿童 HIV 感染率的估计值。我们比较了使用这种设计的样本量和精度与应用于按母婴 HIV 状况和死亡率定义的分层的两阶段不成比例抽样设计的样本量和精度。
儿童中 HIV 的流行率从坦桑尼亚的 0.4%（95%置信区间：0.2 至 0.6）到斯威士兰的 2.8%（95%置信区间：2.2 至 3.4）不等，实际相对标准误差在 11%至 21%之间。在分析中包括的所有国家中，目标设计的预期精度都有所提高，平均平方误差的比例降低了 27%（斯威士兰）至 61%（坦桑尼亚），假设样本量相等。
同时测量儿童 HIV 感染率的成人 HIV 流行率的基于人群的调查应考虑对儿童进行有针对性的抽样，以减少所需的样本量、提高精度并增加接受测试的阳性儿童人数。PHIA 调查的结果可作为未来抽样设计的基线数据。
