**1. Introduction**

Immunization is widely recognized as one of the most important public health interventions for reducing childhood morbidity and mortality [1]. Enormous efforts led to a significant increase in global coverage of the third dose of diphtheria–tetanus–pertussis

**Citation:** Shearer, J.C.; Nava, O.; Prosser, W.; Nawaz, S.; Mulongo, S.; Mambu, T.; Mafuta, E.; Munguambe, K.; Sigauque, B.; Cherima, Y.J.; et al. Uncovering the Drivers of Childhood Immunization Inequality with Caregivers, Community Members and Health System Stakeholders: Results from a Human-Centered Design Study in DRC, Mozambique and Nigeria. *Vaccines* **2023**, *11*, 689. https://doi.org/10.3390/ vaccines11030689

Academic Editor: Pedro Plans-Rubió

Received: 25 January 2023 Revised: 17 February 2023 Accepted: 27 February 2023 Published: 17 March 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

(DTP3) vaccine over the past two decades, reaching its highest point at 86% in 2019, although this fell to 83% in 2020 due to the COVID-19 pandemic, and 81% in 2021 [2]. Immunization services miss millions of children each year, including those who are not fully vaccinated and those considered zero-dose, defined as not having received the first dose of a DTP-containing vaccine. It is estimated that 16 million children were zero-dose in 2020 and 18 million were zero-dose in 2021. These children are at risk of illness or death, and are likely to live in circumstances that further exacerbate this risk [2].

Research exists on the drivers of immunization inequality [3–10], yet most of the existing research focuses either on individual attributes or health system drivers, without analysis of the social and structural processes that produce inequalities [11]. Recent attention to the role of gender in immunization (in)equity is overdue [8,12] but too often, gender is explored alone, without consideration of how it intersects and interacts with other social, institutional, and structural dimensions of inequality, including social determinants of health. Novel research approaches are needed to reconceptualize immunization inequality—and potential solutions to overcoming it—from caregivers' lived perspectives.

This study seeks a way forward to engage and support individuals, caregivers, families, communities, and the health system to co-produce immunization equity. We apply paradigms and approaches from a human-centered design (HCD) and intersectionality [11,13], to reconceptualize the barriers, facilitators, and root causes of no immunization and under-immunization from the perspective of caregivers of infants and young children. When applied to health, intersectionality is the theory that individuals' lives are shaped by multiple social, institutional, and structural axes, that work together and interact to produce advantages or disadvantages [11,13]. Through this lens, we shift towards understanding each caregivers' experience as unique to their situation and the role that all social forces play in empowering or disempowering them. HCD has been used in global health programs to better understand the needs and context of end-users, and to co-create context-appropriate solutions [14], which this study sought to do. In all steps of the study's design and implementation, we sought to increase empathy for caregivers, an important step towards equity and justice.
