Methodology

The Zambia Vaccine Delivery study is a collaboration between Emory University, the Center for Family Health Research in Zambia, the Georgia Institute of Technology, the Bill & Melinda Gates Foundation, and Gates Ventures, as part of the Exemplars in Global Health program. Other collaborators include researchers at the University of Delaware and Yale University.

Exemplar country selection

Filtering criteria were used to identify low-income countries that increased immunization coverage from 2006 to 2016 (see Figure 19). From these candidates, three countries with diverse locations, cultures, and health system attributes were selected for deeper examination. These countries were Nepal, Senegal, and Zambia.

Project frameworks

In this mixed-methods research, multiple frameworks informed data collection and interpretation.

Conceptual framework for vaccine delivery

An existing framework describing the determinants of success in immunization systems¹ was adapted to incorporate contextual factors such as governance, financing, and health care system attributes (see Figure 20). This framework informed analysis of delivery system components.

Frameworks for systems change

Two frameworks informed our research around systems change:

• The Consolidated Framework for Implementation Research serves as a guide to understand the contextual factors that influence the success or failure of implementation of a specific intervention. These include the outer context, the inner (organizational) context, the characteristics of the intervention, the implementation approach, and the individual actors responsible for implementation.²
• The Context and Implementation of Complex Interventions framework comprises three dimensions: context, implementation, and setting. The framework aims to advance the understanding of how and why interventions work.³

Desk review

The study team undertook an extensive review of available information and published data on the state of immunization in Zambia from 2000 to the present. These included coverage data from surveys, the World Health Organization (WHO)/United Nations Children’s Fund (UNICEF) Estimates of National Immunization Coverage, and the Institute for Health Metrics and Evaluation, as well as historic and current health policies, economic conditions, the political context, and other factors that may have impacted the immunization program. The desk review informed the interview guides used in the in-depth research visit, data analysis, and synthesis.

Primary research

Primary research was conducted in two stages. The initial scoping was conducted in February and March 2019. In this stage, key informant interviews (KIIs) were conducted to understand the evolution of immunization programming and the factors thought to contribute to Zambia’s performance in immunization. Altogether, 16 KIIs were conducted with high-level representatives of the Ministry of Health and Ministry of Finance and National Planning and professionals involved in country-level immunization programming. These included representatives of the US Centers for Disease Control and Prevention, PATH, UNICEF, the US Agency for International Development, WHO, and the Zambia National Public Health Institute.

The scoping and desk review informed the second stage of primary research: in-depth KIIs and focus group discussions (FGDs) conducted from October 2019 to February 2020.

The in-depth research was conducted at national, provincial, district, health facility, and community levels. The selection of study provinces and districts aimed for diversity in population density and immunization coverage (see Table 4). Health facilities were selected in collaboration with provincial and district health directors, aiming for facilities with rapid growth in coverage of all three doses of the diphtheria, tetanus, and pertussis vaccine (DTP3; greater than 1% annually) or sustained high coverage of DTP3 (greater than 90%), and representing both high and low population densities. Health facilities located near district capitals were preferred.

Interview guides were informed by the Consolidated Framework for Implementation Research domains and adjusted to local context. All interview guides were piloted before use and adjusted iteratively throughout data collection. KIIs and FGDs were conducted in the predominant language of the participants (Bemba or Nyanja), in person by trained facilitators. KIIs were conducted at the national, provincial, district, and health facility levels to identify (1) the strategies behind current immunization programs; (2) previous immunization activities that occurred during changes in coverage of the first dose of diphtheria, tetanus, and pertussis vaccine (DTP1) and the third dose (DTP3) from 2000 to 2018; and (3) key internal and external actors, stakeholders, and partnerships in the immunization program, both past and present.

At the national level, an initial list of KIIs was developed with the help of Ministry of Health officials. We then used snowball sampling to identify other potential informants. KIIs were conducted with senior managers and directors involved in immunization activities at the ministries of health, finance and national planning, and education. KIIs were also conducted with partner organizations involved in the immunization program, including WHO, UNICEF, PATH, the US Centers for Disease Control and Prevention, the US Agency for International Development, the Churches Health Association of Zambia, and the World Bank.

At the provincial and district levels, KIIs were conducted with health management teams. In health facilities and their communities, KIIs were conducted with the nurse in charge, community health assistants, neighborhood health committee members, community-based volunteers (CBVs), and community leaders (civic, traditional, and religious leaders).

FGDs were conducted at the community level with CBVs and caregivers. The goals of the FGDs were to (1) understand the service provided by the health system, including past and present vaccine interventions; (2) identify CBVs’ roles and responsibilities in the health and immunization sectors; and (3) understand the previous and current factors behind vaccination coverage in their respective communities.

These discussions were organized with the support of district health directors. FGDs had a maximum of eight participants in each discussion and were held in private health facility rooms. Mothers, fathers, grandparents, and CBVs were separated for FGDs. Discussions were conducted in the predominant language of the participants.

FGD participants were selected in advance with the assistance of the health facility nurse in charge or CBVs. CBVs had to serve in the catchment area of the health facility. Mothers had to be between 18 and 45 years old and have a child who was 1 to 2 or 12 to 17 years old. Fathers had to be between 18 and 55 years old and have a child age 17 or younger. Grandmothers had to be above the age of 45 and serve as a primary or secondary caretaker to a child age 17 or younger.

Qualitative data analysis

We conducted a thematic analysis of KII and FGD transcripts to identify the key drivers of success in immunization programs relative to deductive and inductive themes, applying constructs from the Consolidated Framework for Implementation Research and the Context and Implementation of Complex Interventions framework. We considered context and participant roles while uncovering key points, and we triangulated data with historical documents and literature review. Emerging themes were identified and grouped with predetermined research questions and objectives while also accounting for unexpected themes.

Ethical approval

The research protocol was reviewed and approved by the University of Zambia Biomedical Research Ethics Committee (Federal Assurance No. FWA00000338, REF. No. 166-2019) and the National Health Research Authority in Zambia. This study was also approved as exempt human research by the Institutional Review Board of Emory University, Atlanta, Georgia, USA (IRB00111474). This project qualified for exemption from the requirements of federal regulations under 45 CFR 46.104(d)(2). Participation in the KIIs and FGDs was voluntary. Consent forms were read verbatim to participants in their preferred language by a trained interviewer. Participants provided informed consent, either written or with their thumbprint, in the presence of a witness.