Insights into Vaccine Hesitancy from Systems Thinking, Rwanda

"...future research could build on [the] insights and causal loop diagrams to develop a human-centred, collaborative approach to identifying leverage points that could be used to design sustainable interventions for minimizing vaccine hesitancy."

Although national immunisation coverage rates in Rwanda are high, some communities face local disease outbreaks due to underimmunisation. A major driver of underimmunisation is vaccine hesitancy. The World Health Organization (WHO)'s Immunization Agenda 2030 highlights the importance of people-centredness for understanding the context-specific root causes of vaccine hesitancy and for co-designing solutions. This study explores the mechanisms underlying vaccine hesitancy in Rwanda that contributed to local underimmunisation for measles and a subsequent measles outbreak. It analyses immunisation service delivery in both a rural community and a peri-urban community and derives a conceptual model of vaccine hesitancy to assist in the design of sustainable interventions.

The study design was based on an already-published immunisation system diagram (see Figure 1 in the paper). In analysing vaccine uptake, the researchers used systems thinking, human-centred design, and behavioural frameworks. Specifically, they:

• Assessed how underimmunisation was influenced by the 3 so-called immunisation service flows: (i) the vaccinee (child); (ii) the healthcare workforce (nurse); and (iii) vaccine availability (vaccine).
• Sought to understand local factors influencing vaccine hesitancy by: conducting in-depth interviews with 11 vaccination service providers at 11 health centres, collecting secondary data, and interviewing 161 children's caregivers at 2 health centres: one in rural Ramba in Ngororero District, where there was a measles outbreak in 2019, and one in Gahanga in the Kicukiro District, where there had not been a measles outbreak since 2018.
• Used the 3Cs framework - confidence; complacency; and convenience - to categorise factors reported by caregivers and health centre staff.
• Derived causal relationships between behavioural drivers, vaccination intent, and vaccination uptake by analysing the vaccine hesitancy factors identified and presented these relationships in causal loop diagrams, which were validated and explained during 9 additional interviews with health centre staff.

During data collection (2018-2020) at the 11 health centres, the researchers found no evidence of vaccine stockouts in 2018 or 2019. Moreover, there were no human capacity limitations that resulted in immunisation services being unavailable, and national immunisation coverage rates were above 90%. However, measles outbreaks occurred because of a lack of timely immunisation. Thus, the suspected cause was reluctant vaccine uptake rather than limited vaccine availability.

Selected findings:

• Vaccination service providers' perspectives (see Table 2 in the paper):
  • Providers reported that confidence is increased by trust in immunisation service delivery and that a good relationship between caregivers and both nurses and community health workers (CHWs) is key. However, the time health centre staff could spend with each caregiver and the resulting quality of care were affected by an increased workload due to high peri-urban immigration rates of up to 10% per year, paperwork, and other responsibilities.
  • Complacency was successfully reduced by: (i) organisation of 6-monthly mother-and-child health weeks; (ii) regular community meetings (umuganda and w'ababyeyi or mothers' evenings); (iii) educational sessions before vaccination sessions; and (iv) individual contacts between CHWs and caregivers. However, in rural settings, mothers tended to deprioritise or forget immunisation of older children because of other tasks and because they had little contact with health centres in the 6-month interval between the first and second measles and rubella vaccine doses. CHWs were regarded as playing a crucial role in connecting mothers to antenatal care and vaccination services. However, concerns were raised about the sustainability of CHW programmes.
  • With regard to convenience, the main problem mentioned by Expanded Programme on Immunization (EPI) and peri-urban health centre staff was a long waiting time. In rural settings, time-saving strategies such as holding vaccination sessions on market days were regarded as having a positive impact on convenience and also on the provision of nutritional and family planning services. Interviewees from all levels and settings said paper-based data management made it difficult to monitor late immunisations and dropouts.
• Caregivers' perspectives (see Table 3 in the paper):
  • With regard to confidence, caregivers reported no concerns about vaccine quality and trusted vaccines. In rural settings, trust was reported to stem from respect for providers, including nurses and CHWs. CHWs were more often reported as a source of information in rural than in peri-urban settings. The impact of government information campaigns seemed greater in peri-urban settings.
  • In terms of complacency, carelessness and forgetting were considered to be the main reasons for underimmunisation, particularly when mothers had older children, more tasks, and different priorities. Caregivers did not mention misinformation on social media in either setting.
  • Factors affecting convenience varied considerably between rural and peri-urban settings, with differences in travel distances and waiting times. In the rainy season, travelling safely with young children was complicated in rural areas; some people relied completely on outreach services.

The causal relationships between the main factors affecting vaccine hesitancy identified in interviews with vaccination service providers and caregivers are illustrated in 3 causal loop diagrams in Figure 2 of the paper - for confidence, complacency, and convenience, respectively. Figure 3 (see above), which is a composite of these 3 diagrams, indicates that vaccine uptake is governed by 3 key factors: (i) trust in vaccination; (ii) community engagement; and (iii) access to vaccination. As vaccine uptake evolves, 6 feedback loops are activated, illustrating the dynamic nature of the system. The same factors and loops were identified in both rural and peri-urban settings, but their relative impact on vaccination uptake differed. Overall:

• For confidence, reinforcing factors include: (i) respectful relationships with health centre staff and CHWs engender trust in vaccine services; (ii) mothers overcome fear of being late for immunisation when they know the nurse and feel welcome; (iii) multiple contacts between the caregiver and nurse increase trust; and (iv) an entry in the mother-and-child booklet indicating immunisation has been completed is encouraging for both caregivers and their families. Balancing factors include: (i) long wait times; (ii) short contact times between nurse and caregiver; and (iii) suspension of educational sessions before vaccinations during the COVID-19 pandemic.
• For complacency, a reinforcing factor is: (i) a well-protected population experiences fewer cases of disease, which increases the perceived benefit of vaccination and community engagement. Balancing factors include: (i) a decline in cases of disease, which lowers both awareness of the threat to young children and the perceived importance of vaccination; and (ii) caregivers worrying less about their children's health as they grow up.
• For convenience: a reinforcing factor is: (i) families that are healthy, literate, and financially stable are more likely to understand their appointment schedule and can afford to travel to health centres to vaccinate their children. A balancing factor is: (i) the risk of a disease outbreak, which is increased in poorly protected populations.

A comparison of service providers' and caregivers' perspectives in both rural and peri-urban settings showed that similar factors strengthened vaccine uptake: (i) high trust in vaccines and service providers based on personal relationships with health centre staff; (ii) the connecting role of CHWs; and (iii) a strong sense of community. Factors identified as increasing vaccine hesitancy (e.g., service accessibility and inadequate follow-up) differed between service providers and caregivers and between settings, a finding that provides an opportunity for collective learning and for increasing vaccine uptake.

Based on this analysis, the resarchers suggest that, to maintain measles vaccination coverage at the desired level of over 95%, behaviour that increases vaccine uptake, as indicated by loops in the causal loop diagram (Figure 3), must be actively promoted. For example, government-led information and vaccination campaigns, community advocacy, and direct communication from CHWs during home visits can be capitalised on to boost the perceived benefit of vaccination and community engagement.

In short, the study's use of behavioural frameworks and systems thinking revealed vaccine hesitancy mechanisms in Rwandan communities that demonstrate the interrelationship between immunisation services and caregivers' vaccination behaviour. Selected insights for application elsewhere:

• Trust in vaccination and social cohesion are factors that can be leveraged in various settings. However, the differences identified in the study between rural and peri-urban settings in the ease of travel indicate that solutions for vaccine hesitancy and vaccine policy design are dependent on the setting, even for the same vaccine in the same country.
• Community engagement plays a critical role in building system resilience. For instance, communication within communities can be leveraged through CHW programmes that enhance social cohesion. In contrast, the COVID-19 pandemic induced the perception that health centre visits were unsafe. This perception, combined with the temporary cancellation of community awareness activities and educational sessions at health centres, resulted in immunisation being delayed until mid-August 2020.
• The study revealed leverage points that cut across several factors influencing vaccine hesitancy (i.e., one specific intervention can impact multiple loops within the immunisation system). For example, the connecting role of CHWs was pivotal, and they could function as a high-potential leverage point because they have a direct impact on two feedback loops: the balancing convenience loop (i.e., identifying the need for outreach and vaccination campaigns) and the reinforcing complacency loop (i.e., increasing awareness of the benefits of vaccination through home visits).

The researchers conclude by proposing that their systems thinking approach and factors influencing hesitancy identified herein could be integrated with initiatives like the Vaccine Confidence Project, which features a tool for mapping confidence globally.