Clinton Health Access Initiative Inc., Yaoundé, Cameroon.
Institute for Global Health, Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy.
J Glob Health. 2023 Nov 17;13:04136. doi: 10.7189/jogh.13.04136.
Despite growing efforts to improve access to vaccination, millions of children, especially in developing countries, have not received a single dose of diphtheria, tetanus, and pertussis (DTP) vaccine. Consequently, they are often called zero-dose children (ZDC). With limited health resources, prioritising communities for rapid and mass zero-dose catch-up vaccination in missed communities to avert epidemic outbreaks is complicated by unreliable denominators used to compute vaccination coverages. Incorporating other indicators of access and utilisation of vaccination services can help with identifying and ranking missed communities based on the likelihood of finding ZDC. We described the process of generating a scoring method to rank health areas in Cameroon based on their likelihood of containing ZDC.
We used geospatial analysis to compute and aggregate health area characteristics, including hard-to-reach (HTR) areas (defined as areas of settlement above a one- (for urban areas) or 15-kilometre radius (for rural areas) beyond a vaccinating health facility), amount of area covered by slums and new area settlement, and percentage of children unvaccinated for DTP-1. We attributed a weight based on the ability to limit accessibility or utilisation of vaccination services to each characteristic and computed the score as a weighted average of health area characteristics. The health area score ranged from 0 to 1, with higher scores representing a higher likelihood of containing ZDC. We stratified the analysis by rural and urban health areas.
We observed substantial district and regional variations in health area scores, with hotspots health areas (administrative level 4) observed in the Far North (0.83), North (0.81), Adamawa (0.80), East (0.75), and South West (0.67) regions. The Adamawa region had the highest percentage of health areas with the highest score (78%), followed by the East (50%), West (48%), and North (46%) regions. For most regions (Far North, South, South West, Littoral, West, and North West), DTP-1 contributed the most to the score. However, HTR settlement areas within a health area contributed substantially to the overall score in the East, North, and Adamawa regions.
We found substantial variations in health area scores with hotspots in the Far North, North, Adamawa, East, and South West regions. Although DTP-1 could be used as an indicator to identify health areas with ZDC for most communities, HTR settlement area was a valuable indicator in ranking priority health areas in the East, North, and Adamawa regions, further emphasising the need to consider other indicators before prioritisation.
尽管为改善疫苗接种可及性做出了不懈努力，但仍有上百万儿童，尤其是发展中国家的儿童，尚未接种一剂白喉、破伤风和百日咳（DPT）疫苗。因此，他们通常被称为零剂量儿童（ZDC）。由于用于计算疫苗覆盖率的分母不可靠，因此在错过接种的社区中，优先为大量零剂量儿童进行快速补种，以避免疫情爆发，这变得复杂。纳入疫苗服务获取和利用的其他指标有助于根据发现 ZDC 的可能性，对错过接种的社区进行识别和排名。我们描述了一种生成评分方法的过程，该方法可根据包含 ZDC 的可能性对喀麦隆的卫生区进行排名。
我们使用地理空间分析来计算和汇总卫生区特征，包括难以到达的地区（HTR）（定义为居住在接种疫苗的卫生机构 1 公里（城市地区）或 15 公里（农村地区）半径以外的定居点）、贫民窟和新定居点覆盖的区域面积以及未接种 DTP-1 的儿童比例。我们根据每个特征限制疫苗服务可及性或利用能力为其赋予权重，并计算出卫生区特征的加权平均值作为评分。卫生区评分范围为 0 至 1，评分越高表示包含 ZDC 的可能性越大。我们按农村和城市卫生区对分析进行分层。
我们观察到卫生区评分存在显著的地区和区域差异，在极北（0.83）、北方（0.81）、阿达马瓦（0.80）、东方（0.75）和西南（0.67）地区观察到热点卫生区（行政级别 4）。阿达马瓦地区的高评分卫生区比例最高（78%），其次是东方（50%）、西方（48%）和北方（46%）地区。对于大多数地区（极北、南方、西南、滨海、西方和西北），DTP-1 对评分的贡献最大。然而，在东方、北方和阿达马瓦地区，卫生区内的 HTR 定居点对总体评分贡献很大。
我们发现极北、北方、阿达马瓦、东方和西南地区的卫生区评分存在显著差异。尽管 DTP-1 可以作为大多数社区识别 ZDC 卫生区的指标，但 HTR 定居区是对东方、北方和阿达马瓦地区优先卫生区进行排名的有价值指标，进一步强调在进行优先排序之前，需要考虑其他指标。
