"Chanjo Kwa Wakati" - Leveraging community health workers and a responsive digital health system to improve vaccination coverage and timeliness in rural settings

确保公平接种疫苗对于保护所有儿童免受可预防和潜在疾病的侵害至关重要

Ensuring equitable vaccinations is critical for protecting all children against preventable and potentially dangerous infections such as polio, diphtheria, and measles. Yet, numerous studies have highlighted low vaccination coverage and timeliness, particularly among children from resource-limited settings. For example, in Tanzania, only 68% of children receive all basic vaccines that are recommended in the first year of life. Reasons for vaccination inequities are multifaceted; they include low caregiver knowledge about vaccines, and challenges with health service delivery and access. Health service interruptions during the global COVID-19 pandemic have further restricted opportunities for caregiver education, impacted vaccine access, and exacerbated vaccination inequities. Approaches that optimally utilize limited health workforce capacity and rapidly evolving digital health capacity for remote healthcare in resource-limited settings hold great potential for mitigating childhood vaccination inequities. We recently completed (1) a Fogarty-funded study (R21TW010262) that demonstrated the feasibility and efficacy of mobile phone-based reminders and conditional financial incentives for improving the coverage and timeliness of childhood vaccinations, and (2) a community health worker (CHW) intervention that was shown to be acceptable for mitigating caregiver knowledge gaps about childhood vaccines. Building on this prior work and with support from Tanzania’s National Immunization and Vaccine Development program, we propose to evaluate an integrated, community-based, digital intervention for promoting equity in childhood vaccinations. The outreach and educational intervention, called ”Chanjo Kwa Wakati” (“timely vaccination”), is targeted toward recent mothers and comprises a combination of CHW outreach and low-cost digital strategies (autonomous mobile phone-based vaccination promotion messages, reminders, stockout notifications, and incentive offers for timely vaccinations). In Aim 1, we will evaluate the effectiveness of Chanjo Kwa Wakati in promoting the coverage and timeliness of childhood vaccinations in a Type I effectiveness implementation hybrid trial. The trial will involve the staggered implementation of the intervention across catchment areas of 40 rural health facilities in two predominantly rural regions of Tanzania with large numbers of un- or under-vaccinated children. Vaccination outcomes will be analyzed for children born to 1200 women participating in the trial. In Aim 2, we will evaluate implementation factors associated with variations in intervention effectiveness, analyze the cost effectiveness of the intervention, and develop an implementation blueprint to guide scale-up to other settings. In Aim 3, we will evaluate the feasibility and potential efficacy of a machine learning approach for proactively identifying children at risk of non- or delayed vaccinations and validate predictive models using vaccination data gathered in Aim 1. Study findings will inform future implementations and scale up of Chanjo Kwa Wakati, including potential interventions to improve vaccination equity for children living in rural, resource- limited, or underserved communities in the United States.