Chanjo Kwa Wakati - Improving Vaccination Coverage and Timeliness in Rural Settings

The goal of this cluster-randomized type 1 effectiveness implementation hybrid trial is to evaluate whether a community health worker led, integrated digital health intervention (Chanjo Kwa Wakati; "Timely Vaccination" in Kiswahili) can improve vaccination timeliness in rural Tanzania. The hypothesis is that Chanjo Kwa Wakati will improve the timeliness and rates of completion of vaccinations due by age 1 year compared to the standard of care. Researchers will compare outcomes between an early vs. delayed intervention arm, and a prospectively enrolled sample of children with a cross-sectional retrospective sample. This study will address the lack of rigorous evidence on the effectiveness of an community-based digital health intervention for promoting vaccination coverage and timeliness among children from sub-Saharan Africa, and identify implementation strategies to facilitate the deployment of integrated vaccination interventions in low- and middle-income country settings.

Background and Objective:

Tanzania is one of 20 countries where the majority of un- and under-vaccinated children reside. Prior research identified substantial rural-urban disparities in rates and timeliness of childhood vaccination in Tanzania, with children in rural settings being more like to receive delayed or no vaccinations. This type 1 effectiveness implementation hybrid study will evaluate the effect of Chanjo Kwa Wakati ("Timely Vaccination" in Kiswahili), a community-based, integrated digital health intervention, on vaccination timeliness. The intervention combines a vaccination knowledge intervention, mobile phone-based reminders, and incentives with the goal to promote timely childhood vaccinations.

Methods:

The study will be conducted in two predominantly rural regions in Tanzania with high numbers of un- or under-vaccinated children. Forty rural health facilities and their catchment areas ("clusters") will be randomized to an early or delayed onset study arm. From each cluster, three cohorts of mother-child dyads, one retrospective cohort and two prospective cohorts, will be enrolled into the study. For all vaccines due during the first year of life, timeliness (primary outcome) and coverage (secondary outcome) will be observed for 1200 children (600 intervention children and 600 non-intervention children). Study logs, fidelity checklists, quantitative surveys, vaccination records, and qualitative interviews with mothers and key informants will be used to inform the five constructs of the Reach, Effectiveness, Adoption, Implementation and Maintenance (RE-AIM) framework. Results will be used to develop an implementation blueprint that can guide future adaptations, sustainability, and scale-up of Chanjo Kwa Wakati.

Hypothesis:

The hypothesis is that Chanjo Kwa Wakati is effective for increasing the timeliness of childhood vaccinations due by age 1 year compared to the standard of care.

Expected impact:

This study will address the lack of rigorous evidence on the effectiveness of an community-based digital health intervention for promoting vaccination coverage and timeliness among children from sub-Saharan Africa, and identify implementation strategies to facilitate the deployment of integrated vaccination interventions in low- and middle-income country settings.

Eligibility Criteria:
Inclusion Criteria for the Cross-sectional sample:

* mothers of children ages 12-23 months
* residing in the sampling area

Inclusion Criteria for the Longitudinal sample:

* pregnant women in their last trimester of pregnancy
* residing in the sampling area
* expected to reside in the sampling area until the child reaches age 1 year

Exclusion Criteria:

* Women who are not living in catchment areas of participating health facilities (which routinely provide maternal and child health services, including antenatal care and at least weekly routine childhood immunization. Facilities must be operational, must have at least 2 community health workers, and must have reported at least 100 pregnancies or births in the year prior to study implementation.)