Understanding the factors that shape vaccination ecosystem resilience: a qualitative assessment of international expert experiences and perspectives

Introduction

Globally, immunisation prevents an estimated 4–5 million deaths across the age spectrum annually and is a valuable and cost-effective public health intervention.1 The Global Alliance for Vaccines and Immunization (GAVI) quantified that vaccines administered in Gavi-eligible countries between 2000 and 2020 generated >$230 billion (2022 US$) in economic benefits by preventing illness, premature death and disability.2 3 Despite the well-recognised benefits of vaccination, vaccination coverage rates (VCRs), or the proportion of an eligible population that is vaccinated, vary globally, demonstrating a continued need to ensure that vaccination programmes reach their full potential.

At the health system level, various functions work together to effectively deliver quality services (eg, infrastructure, workforce, surveillance data, medical products and technology, finance, governance).4 When exposed to a disruption to the system, such as a vaccine-preventable disease (VPD) outbreak, supply chain interruption or a financial crisis, health system functions may be vulnerable to interruptions that can result in health system strain or collapse.4 System disruptions have also been referred to as ‘shocks’, defined as a ‘sudden and extreme change which impacts a health system, and is thus different from the predictable and enduring health systems stresses, such as aging populations’.5 How a health system responds and adapts to a shock is known as ‘resilience’. The concept of resilience was first applied in Holling and Walker’s seminal work on ecological systems, which has since been studied and applied to health systems.6 Specifically, in examining the Ebola epidemic, Kruk and colleagues defined resilience as the ‘capacity of health actors, institutions, and populations to prepare for and effectively respond to crises; maintain core functions when a crisis hits; and, informed by lessons learned during the crisis, reorganize if conditions require it’.7 During an infectious disease outbreak, resilient health systems can minimise social and economic disruption through ‘engaging people as partners in containment efforts, reducing fear, and hastening resumption of normal activity’.7 Dubé and MacDonald further defined resilient immunisation programmes as those that (1) are able to withstand major shocks and disruptions, (2) quickly adapt to changing circumstances and (3) maintain high vaccine uptake and acceptance over time.8

Within a health system’s infrastructure, vaccination systems form a complex interconnected network or ecosystem. The vaccine ecosystems comprised (1) local, national and international healthcare actors or organisations (eg, healthcare professionals), community and policy/government leaders and (2) sectors that promote user uptake (ie, research and development, manufacturing, procurement and finance, distribution, logistics, and supply chain management, and healthcare, including systems designed to support surveillance and monitoring/tracking).9 Each is responsible for provision of services during periods of stability as well as response and recovery in crisis periods.9 10 Ecosystems face political, economic, environmental (ie, natural disasters/climate change) and sociocultural pressures that are shaped by multiple stakeholders, microsystems and policies, as well as supranational entities and geographical regions. Additionally, the degree to which vaccination is deemed acceptable and impacts subsequent uptake is variable and influenced by multiple factors.11 12 For example, perceptions of vaccine safety or efficacy can impact coverage rates, and lack of vaccine confidence, as well as personal and religious beliefs about vaccination can lead to hesitancy or refusal.

Health system shocks that disrupt the vaccine ecosystem may include conflict and political unrest through destruction and/or displacement of healthcare facilities, healthcare workers, infrastructure, resources and equipment.13 Moreover, ecosystem disruptions can result in VPD outbreaks and losses in programme development investments.14 Since early 2020, the global COVID-19 pandemic has caused substantial disruption to routine vaccination across the life course.15 16 Throughout the pandemic, the core elements of health and vaccination ecosystems have been pressure tested, bringing renewed attention to strategies for developing and maintaining resilience.

Despite the articulation of theoretical frameworks and toolkits around the concept of health systems resilience, there remains limited research examining the resilience of vaccination ecosystems in response to an infectious disease outbreak.17 The primary aim of this study was to identify and describe the key components and attributes of ecosystems that facilitate or impede ecosystem resilience during a crisis or shock.

Methods

Results

Factors that facilitate resilience

Interviewees described various factors that positively support or impact the vaccination ecosystem in their country. Survey participants also were asked to select specific factors that positively impacted the resilience of the ecosystem without further elucidation. Data about positive impacts permitted the identification of factors considered to facilitate vaccination ecosystem resilience (figure 1).

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Figure 1

Factors that facilitate resilience.

The role of stakeholder education about vaccines and VPDs

Interviewees described the importance of a rapid roll-out of public education campaigns in partnership with professional associations. The aim was to counter antivaccination information, support vaccination and encourage conversations between patients and providers about the importance of vaccination. These campaigns were typically approached in two ways. First, public educational campaigns were developed to drive awareness of and health-seeking behaviours around vaccination. Campaigns aimed at healthcare practitioners who administer vaccines were designed to train providers to communicate clearly and effectively about the importance of vaccination to their patients. This served to augment public health education efforts by ensuring that practitioners themselves were (1) cognisant of the effectiveness of vaccination, (2) confident in vaccine administration and (3) equipped to effectively communicate the value of vaccinations to patients and in doing so, engendering trust among the public. Survey responses validated interview findings with ‘educational campaigns for the public’ and ‘educational campaign for health care practitioners’ as the top two factors believed to positively impact vaccination ecosystems.

Interviewees shared that when community organisations and governments collaborated around educational initiatives, such partnerships often resulted in increased community trust about vaccination. Specifically, in Japan, the government’s provision of education around vaccines to specialists in internal medicine, paediatrics, and obstetrics and gynaecology, and midwives led to greater public receptivity. Similarly, in Nigeria, extensive training of healthcare workers such as doctors, nurses and community health workers played a key role in educating the public. One participant described the effectiveness of employing jingles (mass communication on television and radio), photo depictions of communicable diseases and the critical role of patient and immunisation advocacy groups in raising awareness and educating the public about the importance of vaccination.

Investment in vaccination programme financing, infrastructure and delivery

Multiple factors related to financing and investment across the vaccination ecosystem were cited by interviewees as critical drivers to facilitate resilience. Survey participants also ranked ‘increased funding for vaccination programs’ as a factor that positively impacts the resilience of an immunisation system. Interviewees also reported that priority setting and competition for public health resources impacted immunisation policy development. This, in turn, impacts programme financing and inclusion of specific vaccines in National Immunization Program (NIP) schedules, which is fundamental for overall system performance. Interviewees highlighted the importance of enlisting various influencers in the ecosystem—politicians, media figures, advocacy groups and professional societies—to promote government investment in programme financing and persuade decision-makers to enact policy. In the USA, interviewees cited successful elimination of financial barriers as increasing access to and coverage for paediatric vaccination; although generally viewed as a model of success, participants also noted that similar initiatives had not been attempted in adult populations who have been historically undervaccinated due to health-related disparities.

Interviewees also noted that investment in infrastructure, such as vaccine delivery systems that support access, rapid response systems and immunisation information systems (IIS) were key to facilitating resilience. For example, participants from Brazil described how their NIP invested in its vaccination delivery system by building nearly 50 000 vaccination rooms throughout the country; this facilitated greater access among communities who otherwise may have not received vaccination services. This, in turn, led to observable declines in polio, measles and rubella. The importance of rapid response oversight committees available to evaluate and respond to vaccine safety and efficacy crises augmented IIS data and facilitated action during a shock. An interviewee in Spain described the value of a robust, vigilant system where adverse events are rapidly recognised and addressed. An immediate response, coupled with transparency, was credited with building community trust and increasing VCRs in Spain.

In Brazil, a more cohesive IIS helped to effectively address acute and long-term vaccination supply concerns which in turn mitigated VPD outbreaks. One Brazilian interviewee shared that IIS had initially been administered under the direction of federal and state levels. This resulted in data collection gaps across and within regions. However, after transitioning to an IIS system whereby responsibility for data collection was coordinated at the municipal level (the level also responsible for healthcare delivery), data reporting improved considerably. Similarly, Japan has made IIS system improvements that include real-time communicable disease tracking. Nigeria launched an electronic vaccination monitoring system application for real-time tracking of administration, side effects and hesitancy, connected with the National Primary Health Care Development Agency for streamlined monitoring. Select exemplar narratives highlighting the findings are presented in table 1.

Table 1

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Exemplar narratives of factors that facilitate resilience

Factors that impede resilience

Participants were asked to share factors perceived to negatively impact a vaccination ecosystem resilience, as well as identifying specific instances they believed contributed to impeding resilience. Participants overwhelmingly noted the influence of antivaccination movements to undermine confidence and contribute to increased hesitancy. In addition, other factors that have impeded resilience include perceptions and reports of vaccine-related adverse events and lack of investment in vaccination programmes (figure 2).

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Figure 2

Factors that impede resilience.

Vaccine hesitancy and mistrust

Interviewees cited antivaccination movements and vaccine hesitancy as negative impacts on ecosystem resilience, with misinformation about vaccination-related adverse events and subsequent mistrust of vaccine efficacy serving as notable drivers. Nigerian participants described the spread of misinformation about unconfirmed adverse events associated with the oral polio vaccine. Interviewees from multiple countries described how well-respected and revered community leaders—who hold sway among the public—often perpetuated vaccine-related rumours and misinformation. Participants from Japan described how widely publicised media portrayals of alleged adverse events from the human papillomavirus (HPV) vaccine created fear and angst among adolescent girls and their parents, leading to governmental suspension of the programme. This, in turn, impeded resilience and facilitated a precipitous drop in VCRs among the target population. Such depictions demonstrate how the public may focus more on the perceived adverse events and less on the benefit of protection from infectious diseases. Ineffective or inadequate communication strategies to counter misinformation serve to augment the shock, perpetuate mistrust and erode resilience.

Lack of resource investment and lack of workforce development

While investment was identified as a key driver to facilitating resilience, several interviewees also reported that insufficient investment in ecosystem critical resources confers myriad negative impacts. Interviewees shared first-hand their observations of how governing bodies and political actors shaped vaccination priorities and policies, and impeded investment in ecosystem infrastructure. One participant from Brazil described how cost-cutting measures directly led to vaccine shortages, which impacted VCRs in the short term and accelerated VPD outbreaks over the long term. Another Brazilian participant noted the importance of investing in workforce development as high personnel turnover led to disruptions in the delivery system. Participants across settings emphasised how lack of investment in any one critical area of the system impeded overall system resilience. Select exemplar narratives highlighting the findings are presented in table 2.

Table 2

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Exemplar narratives of factors that impede resilience

Discussion

This study sought to identify, elucidate and describe how shocks have impacted vaccination ecosystems and examine divergence between theoretical frameworks of resilience and how resilience manifests in practice. In so doing, we highlight the degree to which key components associated with resilience are inter-related and multifactorial. Through an analysis of the data and theories on health systems resilience, our study reveals the on-the-ground impacts and outcomes that can be mapped back to elements of resilience explicated in the published literature.

In describing the emerging concept of resilience, Fridell et al4 identified several terms (eg, major shock, adapt, maintain, absorb, respond, change, learn, transform, withstand) and characteristics (eg, financing, health workforce, information, leadership and governance, access to projects/technology, service delivery) to describe resilience and the degree to which a health system is equipped to deal with acute shocks and chronic stressors.4 Nuzzo et al26 described capacities needed to achieve and maintain health systems resilience in the wake of an infectious disease shock. Many of the elements described in these works were highlighted by our study participants, for example, the importance of maintaining critical infrastructure, adequately trained workers, timely access to finances, collaboration and communication with partners both inside and outside of the healthcare delivery system, including the integral role the public plays with in the ecosystem with respect to vaccine awareness, access and acceptance.26 27 A notable stressor and impediment to resilient systems described by study participants is the pervasive mistrust in vaccination more generally, be that concerns around vaccine efficacy and safety, or mistrust in the personnel who administer them. The long and complex history around perceptions of vaccine-related side effects has been well established across multiple vaccines and disease areas in the peer-reviewed literature, with vaccine acceptance dependent on public confidence and trust.28–31 It is believed that reversing the trend away from mistrust and towards trust is best operationalised within the specific context at local and regional levels. In examining the resilience of Kenya’s health system, Kagwanja et al32 focused on chronic stressors (rather than acute shocks) and the responses and organisational capacities underpinning the responses.32 In this study, health manager participants reported a wide range of health system stressors related to resource scarcity, lack of clarity in roles, political interference, reduced autonomy in resource allocation and decision-making, and poor human resource management. Everyday resilience emerged from strategies enacted by managers drawing on a combination of organisational capacities depending on the stressor and context.

The COVID-19 pandemic served as a major shock to vaccination ecosystems across the world, resulting in acute and extended stress to all aspects of the global ecosystem. Social distancing measures disrupted essential primary healthcare services and vaccine administration globally.15 16 33–36 UNICEF reported that as a result of the pandemic, 23 million children missed basic vaccinations in 2020 and approximately 17 million of them did not even receive a single vaccine (‘zero dose children’).37 38 The impact was particularly concerning in under-resourced countries where infants and children are at higher risk of VPDs such as polio and diphtheria.35 36 With these disruptions, some governments and health systems have implemented approaches to address low vaccination rates, including engaging non-physician healthcare professionals as vaccinators, leveraging alternative sites for vaccination services and increasing the use of IIS.33 39 Study participants reported substantial disruptions but also opportunities to re-evaluate and strengthen current systems, with addressing vaccine hesitancy and misinformation as a key component. Although vaccine hesitancy has been a historical public health threat, COVID-19 vaccine hesitancy may have spillover effects with other vaccines, especially in the context of declining trust in health experts, political polarisation and the spread of misinformation.40 41

Separately (with the exception of one interview participant from Greece), vaccine mandates and demand side interventions, such as incentives to vaccinate, were not discussed by study participants as a component related to resilience, however were identified as an area to explore more in future work considering it as an important aspect related to vaccine ecosystem resilience. For example, in the USA, vaccines are federally regulated, while vaccine mandate (or exemption) authority rests with individual states where policies may vary; state-level and school-entry mandates have been associated with historical declines in diseases such as measles, mumps, pertussis and polio.42 43 In response to VPD outbreaks and antivaccination movements, some countries have adopted or reformed vaccine mandate policies, with varying degrees of success. Attwell et al compared the construction, introduction/amendment and operation of six vaccine mandates in Australia, France, Germany, Italy, California and Washington; finding that mandates differed in their effects on behaviour, as well as with regard to their structure, exemptions, target populations, consequences and enforcement, with diverse outcomes as far as the degree to which mandates restrict or incentivise behaviours around vaccination.44 Another review of vaccination mandate effectiveness in improving uptake of COVID-19 vaccines in the USA reported that while mandates play a role in promoting uptake of vaccination, it cannot be the only approach as ‘imposing mandates does not remove the need for effective messaging to overcome vaccine hesitancy’.45

Several study participants noted that shocks can serve as an opportunity for vaccine ecosystem stakeholders to assess resilience, develop capacity-building strategies and implement lessons to inform future preparedness and resilience, particularly at the country level. Ozair and Singh46 detailed an approach in their examination of the Indian healthcare system, which was under chronic stress before the COVID-19 pandemic, and how the acute shock of the pandemic created an opportunity to explore innovative short-term and long-term strategies for equitable health services.46 Participants in our study, as well as previously published research, highlight the continued need for developing methodologically sound and relevant research, not just concepts or theories, on how health systems—across stakeholders, sectors and layers—can maintain resilience in the face of a VPD crisis.47 48 We acknowledge that challenges remain in addressing impediments to resilience; however, this study provides formative insights based on vaccination ecosystem stakeholder experiences and areas in which to pursue future rigorous, meaningful and sustained research on resilience in both concept and practice.

Conclusion

To achieve and maintain resilient vaccination ecosystems, participants in this study emphasised the need for investment in comprehensive programme development and implementation, infrastructure and vaccine access. Additionally, educational campaigns to raise awareness, build trust in the effectiveness of health systems and in the providers who administer vaccines, as well as ensure confidence in the efficacy of vaccines were deemed critical to ensuring programmes reach their full potential. Anticipating, identifying, adapting and responding to shocks is central to strengthening vaccination programmes, ensuring ecosystem resilience and protecting against current and future VPD threats. Recent crises, including the COVID-19 pandemic, highlight that resilient vaccine ecosystems require the capacity to swiftly adapt and respond to VPD-related shocks by implementing policy and programmatic changes to help minimise declines in VCRs.