Using Human-Centered Design to Bridge Zero-Dose Vaccine Gap: A Case Study of Ilala District in Tanzania

"Key stakeholders, mainly caregivers, community health workers, healthcare providers, parents, and religious and community leaders, were actively engaged throughout the HCD [human-centred design] process, ensuring that solutions were developed collaboratively with the direct beneficiaries."

Tanzania has a significant number of zero-dose and under-vaccinated children due in part to vaccine hesitancy, which is shaped by social, economic, and cultural dynamics. By prioritising collaboration with end-user communities and engaging deeply with the impacted individuals and groups, the human-centred design (HCD) approach has the potential to address public health challenges, including vaccine hesitancy, in complex sociocultural settings. Conducted from March to December 2023, this study used HCD to aid in identifying, prioritising, and implementing community-centric interventions in the Ilala District of Dar es Salaam, Tanzania, in an effort to increase vaccine demand and close the zero-dose gap by at least 50%.

The HCD approach leverages creativity and empathy to design solutions that are not only tailored to the community's specific needs but that also foster active engagement and collaboration among stakeholders at all levels. The study used persona models with fictional characters to represent key actors' immunisation needs, values, aspirations, abilities, and limitations. Initially, five personas were considered: caregivers, community health workers (CHWs), healthcare workers (HCWs), religious leaders, and community leaders. However, rapid inquiry in Ilala revealed that mothers are often the breadwinners, with grandmothers assuming caregiving roles. In addition, men and traditional healers were identified as key stakeholders in the decision-making process related to immunisation. As a result, the caregiver persona was adapted to include both female caregivers (mothers) and grandmothers, and additional personas for men and traditional healers were created. The study followed the UNICEF Journey to Health and Immunization framework (2020), which takes into account six stages in the health journey, helping identify both barriers and enablers for key stakeholders (personas) in taking and sustaining health- and immunisation-related actions.

Drawing on their extensive experience in health promotion and vaccine delivery, the Ministry of Health (MoH) played a significant role in identifying key stakeholders for participation in various phases of the HCD process, which engaged 483 diverse participants in co-creation workshops. During the two one-week co-creation workshops, immunisation stakeholders in Ilala were brought together to understand immunisation challenges, conduct rapid inquiry research, analyse and synthesise research findings, generate ideas, build prototypes, and engage communities to test and prioritise the prototypes iteratively. A key innovation of this study was conducting multiple rounds of testing of the co-created interventions to challenge assumptions, collect feedback from communities, and uncover more user needs. Specifically, over a three-month period, three weeks were dedicated to planning and implementing one of the prototypes deemed most desirable by the community. 

Given the dual objectives of developing community-centred interventions and building stakeholder capacity in HCD, 24 of the 483 participants were consistently engaged throughout all HCD phases. This approach ensured they acquired the necessary skills to implement the co-created interventions and sustain vaccine uptake efforts using participatory approaches within their communities, workplaces, and healthcare settings. 

Based on a rapid inquiry and observation, multiple barriers to routine immunisation were identified from various perspectives, including those of fathers, female caregivers, CHWs, religious leaders, HCWs, community leaders, and grandmothers. They identified the causes of under-five defaulting and the zero-dose gap, as follows: inadequate support of local community leaders in under-five vaccination sensitisation and surveillance; poor infrastructure in new settlement areas; hesitancy and unwillingness of parents/guardians; absence of house numbers; and limited/time-constrained availability of resources to facilitate mobile immunisation services.

In response, through workshopping, the participants came up with 309 ideas and then made prototypes of the top six ideas in different forms, such as sketches or storyboards or even role play scenarios. These prototypes were refined through multiple iterations using the impact-effort matrix and narrowed down to three solutions: (i) having health facilities notify and alert local leaders about vaccination dates; (ii) engaging parents, children, and grownups who got vaccinated to influence others; and (iii) using local government leaders and house representatives for vaccine advocacy. 

Of these, the solution involving local government leaders and house representatives for vaccine advocacy was implemented. An advocacy strategy was used to enhance the collaboration of the district commissioner (DC), council leaders, and community leaders. During council- and community-level advocacy, the DC championed vaccination to 430 participants. House-to-house mobilisation and sensitisation commenced immediately after the advocacy meetings in 26 wards. Each of the 189 CHWs paired with an HCW was assigned a daily house-to-house target of 40 households, assuming an average of 4 families per household and 160 families per day. Special tools were created to gather and organise vaccination data at community, ward, and council levels. The tool was designed to record the number of families reached, zero-dose cases addressed, defaulter cases resolved, and the total count of children in each family and household.

This study observed that the majority of participants (council and local community leaders, health workers, community health workers, and grassroots communities) held positive views of the HCD framework for employing community-based solutions to address vaccination challenges among under-fives and bridge the zero-dose and vaccination defaulting gaps in the study area. Reportedly, most families were cooperative and loved empowering CHWs to mobilise families alongside HCWs. A notable recommendation was that prior notifications should be provided through public address systems, radio, and TV.

The findings reveal that the HCD framework was impactful in increasing collaborations/cooperation with local government leaders and community ownership of the under-five vaccination initiative. As a result, 67,145 houses (104% of the goal) were reached, surpassing the initial target of 64,800 houses, and 131,088 families, equal to 83% of the targeted 156,995 households, were sensitised through a home-to-home campaign approach. This effort reached 387 zero-dose children out of 2,550 and identified many defaulters. These findings confirm that "face-to-face interpersonal communication through house-to-house vaccination advocacy effectively addresses the zero-dose gap and reaches vaccine defaulters. This approach facilitates the accurate capture of vaccination data and mitigates hesitancy and negative influences often associated with mass vaccination campaigns."

Table 9 in the paper depicts the theory of change for each persona built from identified barriers and co-created ideas. For instance, to have increased vaccine coverage in Ilala by 50%, CHWs need to be empowered to take on responsibilities such as administering vaccines, keeping records, and weighing babies. As a result, the workload for HCWs is significantly reduced. This leads to improved work–life balance for HCWs, resulting in a more positive clinic environment and the potential to extend clinic hours. As a result, families are more likely to attend and support regular healthcare services, leading to increased trust and accessibility.

In conclusion: "HCD helps overcome community hesitancy and misconceptions about vaccination by addressing the unique needs of each community and co-designing relevant, tailored interventions. The house-to-house campaigns implemented as part of the proposed community centric interventions raised awareness, increased vaccine uptake, and strengthened the community’s role in health advocacy. This demonstrates that applying HCD principles in public health interventions can effectively tackle challenges like zero-dose vaccination while fostering community engagement and sustainable change." This framework can be pre-tested in other districts of Tanzania to determine its efficacy in eradicating the country's zero-dose gap and under-vaccination of under-fives.

Full list of authors, with institutional affiliations: Simon Martin Nzilibili, Ministry of Health, Tanzania; Hellen Maziku, University of Dar es Salaam; Awet Araya, UNICEF Tanzania Country Office; Ruthbetha Kateule, University of Dar es Salaam; Millenium Anthony Malamla, University of Dar es Salaam; Suna Salum, University of Dar es Salaam; Furaha Kyesi, Ministry of Health, Tanzania; Lotalis Gadau, Ministry of Health, Tanzania; Tumaini Menson Haonga, Ministry of Health, Tanzania; Florian Tinuga, Ministry of Health, Tanzania; Rashid Mfaume, Regional Administration and Local Government, Dodoma, Tanzania; Zaitun Hamza, Dar es Salaam City Council; Georgina Joachim, Ministry of Health, Tanzania; Alice Geofrey Mwiru, UNICEF Tanzania Country Office; Alex Benson, University of Dar es Salaam; Oscar Kapela, Ministry of Health, Tanzania; Ona Machangu, Ministry of Health, Tanzania; Norman Jonas, Ministry of Health, Tanzania; Ntuli Kapologwe, Ministry of Health, Tanzania