Applying a Social-Ecological Model to Understand Factors Impacting Demand for Childhood Vaccinations in Nigeria, Uganda, and Guinea

"...models examining demand for vaccination may underestimate the complexity of the issue by not incorporating a sufficient range of contextual factors, which may in turn impede the design of optimal solutions."

Much scholarship on demand for vaccination in sub-Saharan Africa considers barriers primary caregivers (usually mothers) face when seeking immunisation services. In concert with that focus, many frameworks, such as the COM-B model, may not engage with the full range of drivers and barriers, such as relationship dynamics, interactions with authority figures, or social norms, that a mother may face. This study aimed to build a wider understanding of vaccine demand by applying an adapted socio-ecological model (SEM) to analyse 158 interviews with primary caregivers and fathers of young children, as well as community influencers, in Nigeria, Uganda, and Guinea.

The SEM emphasises the inter-relations between individuals, their environment, and the wider social context. Several different versions of the SEM exist in the literature; the researchers adapted these frameworks to ensure that the entire life context of the study's participants could be adequately encompassed. Their model posits that decisions are affected by the interaction of four nested and interrelated systems:

• Microsystem: the immediate environment in which the individual lives, including relationships with family and romantic partners;
• Mesosystem: the interrelationships between different microsystems - for example, the individual's spouse and their mother;
• Exosystem: the formal or informal institutions the person interacts with; and
• Macrosystem: the social and cultural values and ideologies in a person's context.

There are two key differences in the SEM adopted here compared to versions found in the literature: (i) The researchers removed the personal system, as their research question focused on contextual factors, not individual decision-making processes; and (ii) they have a different understanding of the exosystem, which is sometimes understood as the ways in which social settings interact indirectly with the person under consideration via their microsystems.

Interviews were conducted using semi-structured discussion guides, informed by a literature review, the results of a formative ethnographic study, and conversations with stakeholders in each of the three countries, including Expanded Programme on Immunization (EPI) representatives and government health authorities. Interviews took place in three regions per country to ensure a spread of vaccination coverage rates, ethnic groups, and geographic areas. The interviews took place between October and December 2019 in Nigeria, between June and July 2020 in Uganda, and between January and March 2021 in Guinea.

The researchers found that several factors come together to inform a primary caregiver's demand for vaccination, including the following (illustrated by quotations in the text):

• Microsystem: Across study geographies, the most important individuals in terms of informing vaccination behaviour are the primary caregiver's husband, mother/mother-in-law, community elders/religious leaders, and in some cases, neighbours and friends. For example, the latter groups may play a normative role in signalling to primary caregivers and other family members what is acceptable or unacceptable vaccination behaviour in the community. Their chief role may be in bringing in alternative points of view, which primary caregivers can then build into their conception of vaccination. This may include stories of adverse events, vaccination rumours and conspiracy theories, or other stories about the lived experience of vaccination.
• Mesosystem: Many of the primary caregiver's decisions take place at the interface of her relationship with her husband and her acquired membership of his family, and her relationships with her family of birth. Through marriage, she is considered to have become part of her husband's family, but she also retains close links with her family of birth, which includes advice on child rearing. A primary caregiver may make use of her membership of overlapping microsystems to take some level of decision-making control on the topic.
• Exosystem: Confidence in national governments and international institutions is low across the three countries, particularly in Guinea, where it appears that the response to Ebola further eroded trust in public institutions. Vaccines can be understood by primary caregivers as extensions of the perceived inefficacy of the state to provide for the population or as symbolic of encroachment of international institutions on domestic affairs. The experience of healthcare systems - e.g., inaccessible facilities, long queues, frequent stockouts, poor experience of interactions with healthcare workers, and lack of information about side effects of vaccination - reduce primary caregivers' desire to return for future doses. The primary caregiver's physical and financial circumstances, which may be considered part of the exosystem, also have an impact on demand for vaccination.
• Macrosystem: Cultural values, traditions, and norms influence a parent's demand for vaccination, including religion, traditional medicine, and hygiene. For example, many respondents reported that religious teachings reinforce the authority of a husband over his wife, which then makes it more difficult for a female primary caregiver to contradict her husband on vaccination matters. In this way, religion becomes important not for its direct impact on vaccination but, rather, on how it influences relations at the levels of the microsystem.

The researchers suggest that these findings are consistent with past studies but may enhance understanding of vaccine demand by examining the role of the primary caregiver's interacting microsystems in detail, rethinking the roles of traditional medicine and religious belief, and questioning the assumption that the decision is primarily in the hands of the child's mother. For example, the results of this study feature detailed descriptions of how community leaders inform decision-making within families, and so could be used to design more robust community-based programmes.

Per the researchers, "The involvement of several individuals in vaccination decision-making suggests that 'whole family' or 'whole community' intervention approaches, which encourage entire families or communities to work towards a desired endpoint and have shown some success in other policy areas and settings, could be appropriate to encourage vaccination in Sub-Saharan Africa...[I]nterventions should work with a community's religious and traditional norms rather than attempt to circumnavigate or supplant them."

In conclusion: "Using a Socio-Ecological Model suggests that the decision to vaccinate a child can be viewed as the product of a complex relationship between interpersonal, community, institutional and environmental factors which are inextricably linked....This understanding can be used to inform the design of more holistic interventions to encourage vaccination uptake..." Such interventions, potentially geared toward reaching families and communities instead of individuals, "could be beneficial in creating and sustaining demand for vaccinations."