Investigating the contribution of geographic accessibility and vaccine delivery channels to untimely measles vaccination and zero-dose prevalence in The Gambia: implications for disease outbreaks

仅在2021年，全球就有2500万儿童没有接种第一剂白喉-破伤风-百日咳- 含疫苗(DTP1)。这些人中的绝大多数-生活在低收入和中等收入- 收入国家。此外，许多儿童接种了第一剂含有麻疹的疫苗。 (MCV1)比预定时间晚得多，因此在最终被感染之前有很大的风险被感染 接种疫苗，并可能导致次优的群体免疫。在冈比亚，最近出现了一股热潮 麻疹，截至2022年年中的病例比2020年的数字增加了6倍，尽管实现了 在过去十年中，MCV1的最低覆盖率为90%。最近的数据表明，有很大一部分 根据国家疫苗接种的规定，疫苗接种被推迟或没有以适合年龄的方式提供 窗户。此外，不合时宜MCV1和零剂量被认为在某些偏远地区共存和聚集 并可能导致次优的群体免疫力。PI，Dr Oghenebrume Wariri将应用小说 绘制未及时接种麻疹疫苗和零疫苗接种的亚群的时空建模方法 在精细空间尺度上的剂量，并检查与次优群体免疫和麻疹风险的潜在联系 疫情爆发。他还将研究地理上的可达性如何影响例程的吸收和交付 冈比亚的疫苗接种。该项目将利用来自健康和人口统计的纵向队列数据 冈比亚的监测系统，以及覆盖冈比亚农村人口的生物库血清样本 冈比亚的江西地区。这个K43奖项有四个具体目的：1)确定 冈比亚高空间分辨率下未及时接种MCV1和零剂量儿童的时空模式；2)至 确定不合时宜的MCV1聚集性位置与麻疹之间是否存在时空关系 冈比亚的人口免疫力；3)调查地理可达性的贡献(在 家庭和疫苗接种站；以及固定疫苗接种站和外展疫苗接种站之间)到零剂量流行 和延迟的MCV1；4)对常规疫苗接种服务的地理访问进行建模，以了解 目前的疫苗提供渠道，并有可能确定疫苗接种诊所和哨所的最佳位置。 这项K43奖将使Wariri博士在地理空间和传染病方面拥有新的技能和能力 模特、手稿和赠款写作。瓦里里博士将与一个多学科指导委员会合作 由国际公认的非洲、英国和美国的疫苗、人口免疫方面的专家组成 和传染病建模，以及地理空间建模。拟议的研究与一项 结构化的指导和培训计划，包括授课课程和研讨会，旨在促进 博士-发展独立资助的传染病和空间流行病学的长期目标 与Fogarty International的使命一致的研究计划，重点是非洲的疫苗接种 中心。

In 2021 alone, 25 million children globally did not receive the first dose of the diphtheria-tetanus-pertussis- containing vaccine (DTP1). The vast majority of these - live in low-income and middle- income countries. In addition, many children received their first dose of the measles-containing vaccine (MCV1) much later than scheduled, thus, are at significant risk of becoming infected before they are eventually vaccinated and may contribute to suboptimal herd immunity. In The Gambia, there is a recent upsurge of measles, with a 6-fold increase in cases as of mid-2022 compared to 2020 figures despite achieving a minimum MCV1coverage of 90% over the last decade. Recent data suggest that a large proportion of vaccinations are delayed or not delivered in an age-appropriate manner, according to the national vaccination windows. In addition, untimely MCV1 and zero-dose are thought to co-exist and clustered in certain remote communities and may contribute to suboptimal herd immunity. The PI, Dr Oghenebrume Wariri will apply novel spatiotemporal modelling approaches to map the subpopulation with untimely measles vaccination and zero- dose at fine-spatial scale and examine potential links with suboptimal herd immunity and risk of measles outbreaks. He will also examine how geographic accessibility shapes the uptake and delivery of routine vaccination in The Gambia. The project will leverage longitudinal cohort data from Health and Demographic Surveillance Systems in The Gambia, and bio-banked serological samples covering rural populations in the Kiang West District of The Gambia. There are four specific aims for this K43 award: 1) to determine the spatiotemporal pattern of untimely MCV1 and zero-dose children at high-spatial resolution in The Gambia; 2) to determine if there is a spatiotemporal relationship between cluster location of untimely MCV1 and measles population immunity in The Gambia; 3) To investigate the contribution of geographic accessibility (between households and vaccination posts; and between fixed and outreach vaccination posts) to zero-dose prevalence and delayed MCV1; 4) to model geographic access to routine vaccination services to understand the utility of the current vaccine delivery channels and potentially identify optimal locations of vaccination clinics and posts. This K43 Award will equip Dr Wariri with novel skills and competencies in geospatial and infectious disease modelling, manuscript and grant writing. Dr Wariri will be working with a multi-disciplinary mentoring committee comprising internationally-recognised African, UK, and US-based experts in vaccinology, population immunity and infectious diseases modelling, and geospatial modelling. The proposed research, in combination with a structured mentoring and training plan that includes didactic courses and workshops, is designed to facilitate Dr. -term goal of developing an independently funded infectious diseases and spatial epidemiology research program focussed on vaccination in Africa, consistent with the mission of the Fogarty International Centre.