Introduction

Since the identification of the Ebola virus in the Democratic Republic of the Congo (DRC) in 1976, the country has experienced recurrent Ebola Virus Disease (EVD) outbreaks, with increasing frequency in recent years [1]. The 2018-2020 EVD outbreak in Eastern DRC was the largest in the country’s history and the second largest EVD outbreak globally, resulting in over 3,481 cases (3,323 confirmed, 158 probable) and a case fatality rate of 66% [2]. At the time, only experimental Ebola vaccine doses were available for use in the DRC, administered under an Expanded Access/Compassionate use protocol as recommended by the World Health Organization (WHO)’s Strategic Advisory Group of Experts on Immunization (SAGE) [3,4]. The vaccine was deployed using a ring vaccination strategy, which involved vaccinating contacts and contacts of contacts of EVD cases to interrupt disease transmission [5]. However, the scale and geographic extent of the outbreak exposed critical challenges in the Ebola response and revealed diverse community reactions to vaccination efforts.

The response was also challenged by the complex realities of Eastern DRC, including active conflict, population displacement, a fragile health system, and widespread distrust of both government and foreign actors [6–8]. Although the ring vaccination strategy was implemented, uptake was hindered by persistent community resistance and fears about the vaccine’s safety and intent. Misinformation and rumors, such as suspicions that the vaccine might cause Ebola, led to refusals and, in some cases, violence against response personnel [7]. While trust in institutions was identified as a predictor of vaccine acceptance during the early phase of the outbreak, the sociopolitical context, including historical marginalization and unmet basic needs, continued to shape public skepticism [7]. Community feedback mechanisms provided broad insights into public sentiment, but there remains a lack of in-depth understanding of the local drivers of Ebola vaccine acceptance, especially among healthcare workers and affected communities in Eastern DRC.

Insights from the 2014–2016 West Africa Ebola outbreak highlighted the complex behavioral drivers behind vaccine acceptance, including altruistic motivations, perceived risk, trust in response teams, and broader concerns related to power, fairness, and social justice [8]. Given the increasing number of outbreaks and new focus on preventive Ebola vaccine use, there is a need for updated insights into community perceptions of the vaccine [1,9,10]. Understanding these perceptions is vital for informing effective strategies to improve vaccine uptake in both current and future outbreak responses.

The WHO SAGE vaccine hesitancy working group defines vaccine hesitancy as the delay in acceptance or refusal of vaccines despite the availability of vaccination services [11]. To better understand the roots of hesitancy, the SAGE working group developed the confidence, complacency, and convenience (i.e., “three Cs”) model which posits that vaccine hesitancy arises from (i) a lack of confidence in the safety and effectiveness of the vaccine and the system recommending and delivering it; (ii) complacency, or the belief that the disease poses minimal risk and vaccination is unnecessary; and (iii) convenience barriers, such as difficulties with access, affordability, or the appeal of vaccination services [12]. Vaccine hesitancy is shaped by a complex interaction of cultural, social, psychological, and systemic factors, particularly in the context of EVD outbreaks that strain healthcare infrastructure and challenge public trust.

In the DRC, where EVD outbreaks remain a recurrent threat, it is critical to understand the local sociocultural and contextual factors that shape vaccine perceptions. Comprehensive qualitative research can provide valuable insights into these dynamics, helping bridge the gap between public health recommendations and community realities. This study aimed to explore the factors influencing Ebola vaccine acceptance among communities affected by the 2018–2020 EVD outbreak in eastern DRC. Additionally, we sought input from both community members and key informants on strategies to strengthen vaccine delivery and improve future outbreak response efforts. The findings are intended to inform the design of community-centered approaches that build trust, promote engagement, and address vaccine hesitancy in meaningful and locally relevant ways.

Methods

Data collection

Data collection activities included FGDs and KIIs, conducted during July 27 and August 10 2021. These activities were conducted in-person and in the participants’ language of choice by data collectors trained in qualitative research and fluent in French, Swahili and Kinande, the predominant local languages. This occurred during ongoing COVID-19 transmission and thus safety procedures included social distancing and the use of face masks. Interviewers obtained verbal informed consent from all participants prior to data collection.

Inclusion criteria were age over 18 years, residency in one of the targeted health zones (Beni, Butembo, or Mabalako) during the (DRC’s 10th Ebola outbreak, and willingness to provide verbal informed consent. Participants in FGDs were either survivors of the 10th Ebola outbreak or neighbors of survivors (likely case contacts) who were part of the community group prioritized for vaccination with the limited doses of the rVSV-ZEBOV Ebola vaccine available at the time. HCWs and frontline workers (FLWs) were included only if they had worked in a health facility within the targeted health zones during the outbreak and were among those prioritized for vaccination. In this study, ‘frontline workers’ refers to individuals identified during recruitment as being directly involved in the Ebola response, but not necessarily in clinical roles. Key informants were individuals who held leadership roles during the outbreak, either in the community or within governmental or nongovernmental organizations involved in the Ebola vaccination effort. All interviews were audio-recorded with permission and field notes were taken. FGDs lasted approximately 90 minutes, and KIIs about 60 minutes.

We used a semi-structured guide for the FGDs and KIIs to enable the exploration of a consistent set of questions while at the same time providing the flexibility to probe topics specific to the respondents’ community role and Ebola vaccination status. Participants were asked questions around topic areas expected to influence vaccine uptake including perceived risk of disease; communications (including rumors, misinformation, sources of information, community engagement); societal factors (including religion, community leaders, government, security concerns); health systems (e.g., vaccination teams, geography, logistics); and vaccine specific factors (e.g., safety and efficacy). These topic areas were informed by a literature review, community feedback documented in reports by local health authorities during the outbreak, and direct input from those authorities. Depending on their Ebola vaccination status, respondents were asked their reasons for accepting or refusing vaccination when offered.

The participant characteristics, by health zone, for the 33 FGDs and 15 KIIs that were conducted across Beni, Butembo, and Mabalako health zones are shown in Tables 1 and 2, respectively. A total of 263 participants participated in the FGDs, with some variation by health zone.

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Table 1. Focus Groups conducted by health zone, Democratic Republic of the Congo, 2021. Values represent number of FGDs; numbers in parentheses indicate number of participants.

https://doi.org/10.1371/journal.pone.0346572.t001

Download:

• PPT
  PowerPoint slide
• PNG
  larger image
• TIFF
  original image

Table 2. Key Informant Interviews conducted by health zone, Democratic Republic of the Congo, 2021.

https://doi.org/10.1371/journal.pone.0346572.t002

Results

Thematic analysis yielded several predominant topic areas across FGDs and KIIs including barriers to vaccination, misinformation, sources of information, vaccine confidence, perceptions of the response teams, and reasons for vaccination, and community-based recommendations for improving vaccine confidence. These topic areas were then interpreted and presented using the “three Cs” model of vaccine hesitancy framework, which organizes the findings under the constructs of Vaccine Confidence, Complacency, and Convenience.

Discussion

A central finding from this study is that low vaccine confidence, driven by concerns about the vaccine itself, mistrust in the institutions or individuals delivering it, and skepticism about its deployment, significantly affected acceptance of the Ebola vaccine. This mistrust, particularly in the context of the pre-licensure vaccination campaign that occurred under investigational protocols, likely compounded concerns that the experimental vaccine may not be safe. Many respondents noted the lengthy consent forms and the extended follow-up for adverse events, which contributed to perceptions that the vaccine was not fully trusted or tested. This perception, coupled with a legacy of political instability and distrust in both domestic and international actors perceived as outsiders, significantly undermined vaccine confidence [7]. As the vaccine is now licensed, such barriers may be mitigated in future implementation efforts.

This study builds upon prior research into the sociocultural dynamics that drove vaccine acceptance during the 2018–2020 outbreak in Eastern DRC [7,22]. Study findings also reflect broader vaccine hesitancy patterns documented during other vaccination efforts in the DRC, including COVID-19, cholera, and measles responses [23–26]. Across these contexts, mistrust in government and external actors, circulating misinformation, and perceptions of inequitable access have repeatedly undermined vaccine confidence, suggesting that Ebola vaccine acceptance reflects deep-rooted structural and historical dynamics rather than disease-specific concerns alone. Given the increasing frequency of EVD and other outbreaks of international concern in the DRC, and the important role that vaccines play in their control, our findings on vaccine confidence and acceptance provide critical insights useful for policymakers and outbreak response teams into how communities navigate vaccination decisions in high-risk, conflict-affected settings.

While previous quantitative studies have reported overall high vaccine uptake among HCWs in DRC, our qualitative findings revealed more complex attitudes and motivations for vaccination [14,15]. Many reported being vaccinated due to the perceived necessity for protection in their line of work. For others, vaccine uptake was driven more by institutional mandates rather than by perceived benefits, suggesting a dynamic of coerced compliance rather than voluntary participation resulting from confidence in the vaccine’s effectiveness. Similar tensions between professional obligation, autonomy, and trust have been documented during COVID-19 vaccination campaigns in the DRC [27]. This interplay between confidence in the vaccine itself, confidence in the voluntary nature of the vaccination process and trust in the delivery system reinforces the need for more nuanced models of vaccine decision-making, particularly for HCWs who are both at high-risk and are well-positioned to influence vaccination intentions within their community [12]. Lessons from COVID-19 and influenza vaccination mandates indicate mixed HCW attitudes, with concerns about autonomy and trust in institutions affecting both uptake and public perception [28]. Future research is needed to explore the implications and ethical considerations surrounding mandatory Ebola vaccination policies for HCWs and other individuals at occupational risk and their influence on community vaccine acceptance.

Our results suggest that widespread misinformation about the vaccine’s potential to cause death, infertility, and long-term health effects, particularly for pregnant women, fueled hesitancy. These rumors were exacerbated by inconsistent messaging, insufficient and ineffective communication strategies. A key theme that emerged was the need for clear, transparent, and trusted information about the vaccine from reliable sources, including balanced information detailing both the advantages and potential risks of the vaccine. This underscores the critical need for transparent communication strategies that empower individuals to make informed decisions, supporting findings from similar studies [14,15]. As misinformation continues to play a significant role in shaping public perception of vaccines, the delivery of accurate, evidence-based information through trusted and competent local figures is essential.

Some community members expressed complacency toward vaccination, either because they believed they were not at risk or because they had survived previous outbreaks. Others cited religious beliefs as a protective factor against EVD, perceiving divine intervention as more trustworthy than vaccination [29]. Future research should explore the willingness to be vaccinated in contexts of perceived low disease risk, such as during post-outbreak preventive vaccination campaigns. For example, previous calls for the preventive vaccination of contacts of Ebola virus disease survivors to interrupt transmission in areas with recurrent outbreaks, highlight the need to examine the acceptability of such strategies [9].

Religious beliefs also emerged as a complex factor influencing vaccine acceptance. While some individuals saw faith-based protection as an alternative to vaccination, others recognized the potential of religious leaders to encourage vaccine uptake. Faith leaders and community elders were often seen as more trustworthy than official health authorities, a pattern observed across vaccine contexts, including cholera and COVID-19, in the DRC and elsewhere in sub-Saharan Africa [29,30]. While some religious messages and figures discouraged vaccination, others played a critical role in encouraging uptake. The dual role of religion highlights its importance in either amplifying or mitigating hesitancy. Notably, the quantitative phase of this study found that higher religiosity was associated with greater vaccine uptake, suggesting that religious engagement may support acceptance [15]. Future vaccination campaigns in similar settings where religion is deeply ingrained should therefore carefully consider the importance of aligning public health messages with local religious values to maximize success.

Logistical barriers, including long wait times, distant vaccination sites, and burdensome consent processes hindered access to vaccination. Some participants viewed the ring vaccination strategy, focused on the vaccination of social contacts of EVD cases, as discriminatory. While others believed that only the elite or politically connected received timely access or a more efficacious version of the vaccine. These barriers reinforced broader frustrations with the inequities perceived in the Ebola response that have been previously documented [31]. Ring vaccination was a pragmatic response to limited vaccine supply and an expanding outbreak, but its rationale was often unclear to communities, contributing to perceptions of favoritism. While population-based approaches such as geographic or mass vaccination may have been viewed as more equitable, they were not feasible under the circumstances. Strengthening communication around the rationale for vaccination strategies, and ensuring that these strategies are appropriately contextualized, is vital for fostering trust and improving uptake.

Vaccine perceptions were deeply entangled with political narratives. In a region scarred by decades of conflict, including violence reportedly perpetrated by armed groups from outside the country, participants frequently interpreted response and vaccination efforts through a lens of marginalization and control. Conspiracy theories about the true purpose of the vaccine were common, especially regarding international motives as others have noted elsewhere [7]. The disproportionate mobilization of resources for the Ebola outbreak control and vaccination efforts, compared to those allocated for other community needs including endemic diseases, along with the influx of international actors in the response, also contributed to alienation and suspicion.

Sustainable, community-driven vaccination efforts are essential for improving acceptance. Our findings support the growing recognition that continuous community engagement, particularly through the involvement of trusted and competent local leaders and influencers, builds long-term trust and reduces skepticism [32]. When vaccination campaigns are locally owned and embedded in the community’s social fabric, they are more likely to be effective and accepted. Localized health systems that reflect the cultural, social, and political realities of their communities are better equipped to foster adherence to health interventions [33]. In settings marked by institutional mistrust and a perception of foreign actors as outsiders, empowering local healthcare providers, religious leaders, and other trusted figures is key to ensuring health efforts resonate and gain legitimacy.

Especially in low-trust, conflict-affected settings, implementing health interventions through long-term, community-centered engagement can be challenging, yet remains essential. Our study reinforces that effective engagement must be sustained, adaptive, and integrated within broader health system strengthening efforts. Involving communities and FLWs, throughout both response and recovery phases creates feedback loops, improves communication, and promotes local ownership of public health strategies [32]. Future inquiry should also examine the relative impact of community engagement and social mobilization activities during outbreak response compared to preventive vaccination campaigns. Understanding these dynamics will help tailor engagement strategies to different phases of outbreak risk.

Findings from this study suggest several actionable strategies for improving vaccine uptake in conflict-affected outbreak contexts. These include co-developing culturally relevant communication materials with local communities; training and empowering trusted local leaders to serve as vaccine advocates; and ensuring equitable vaccine distribution to avoid perceptions of favoritism. Additionally, consent processes should be clearly explained and adapted to local contexts. Early in the outbreak, individually delivered consent under compassionate use protocols was perceived by some as burdensome or isolating. Later shifts to group education with individual consent were more acceptable, highlighting the importance of balancing ethical standards with culturally and logistically appropriate approaches. Finally, strengthening local health system capacity to reinforce long-term trust is crucial, as is sustaining community engagement beyond emergency phases to foster continuity and trust. Embedding anthropological and social science perspectives into response planning and evaluation may further support culturally grounded and responsive public health strategies.

Limitations

While this study provides valuable insights into Ebola vaccine decision-making during the 2018–2020 outbreak in Eastern DRC, several limitations warrant consideration. The findings are context-specific and may not be generalizable to all EVD-affected settings, particularly given the unique sociopolitical dynamics in North Kivu. The qualitative design, while allowing for depth and nuance, involved a relatively localized sample, which may not fully represent the broader population or diverse subgroups.

Additionally, the retrospective nature of the study introduces potential recall bias, as participants were reflecting on experiences that may have evolved over time. The interviews were completed after the outbreak and during the early stages of the COVID-19 pandemic, which may have influenced how participants framed their experiences with Ebola vaccination. The heightened global attention to vaccination and public health during this period could have shaped perceptions of trust, risk, and institutional response, potentially prompting comparisons between the two outbreaks. Language barriers and researcher positionality may have influenced responses provided by participants, though these risks were mitigated through training local researchers, providing preferred language options for data collection, and culturally adapted protocols.

Despite these limitations, the study presents several important strengths. By capturing community perceptions during the pre-licensure phase of Ebola vaccine deployment, the research offers a critical baseline that future studies can build upon to assess how attitudes, trust, and hesitancy may evolve in post-licensure contexts or during preventive campaigns. This temporal positioning makes the study especially valuable for comparative analysis as the Ebola vaccine becomes more integrated into routine preparedness strategies [34].

Moreover, the qualitative approach enabled deep exploration of how trust, misinformation, and political context shape vaccine decisions; factors often missed in quantitative surveys. For example, while quantitative findings from the broader study showed high uptake and associations with trust, risk perception, and religiosity, our qualitative data revealed deeper complexities such as perceived coercion among HCWs and tensions between vaccine acceptance and religious beliefs. By capturing these lived experiences, this study adds important context to the survey data and highlights how sociopolitical dynamics shape vaccine decisions in fragile settings. Conducting the study in a conflict-affected setting added complexity but also provided a rare opportunity to examine vaccine acceptance under conditions of institutional fragility.

The active involvement of local researchers and community liaisons enhanced trust, cultural relevance, and data quality, offering a methodological model for research in similarly sensitive environments. Finally, by applying the WHO SAGE 3Cs model, the study offers a focused and policy-relevant analysis grounded in a framework that has been used in outbreak and emergency vaccination research [12]. Although more recent frameworks provide expanded constructs to capture additional dimensions of vaccine acceptance, the 3Cs remain foundational, and particularly suited for identifying primary behavioral determinants in high-risk, resource-constrained environments [35,36]. Our use of this model prioritized conceptual clarity and applicability, offering a strong foundation for future research to build upon.

Conclusion

This study offers a critical, context-specific exploration of the sociocultural drivers of Ebola vaccine acceptance and hesitancy during the 2018–2020 outbreak in Eastern DRC. Conducted in a region marked by armed conflict, institutional fragility, and widespread mistrust, the study provides an in-depth understanding of how confidence, perceived risk, access, and socio-political dynamics influence vaccination decisions. Through FGDs and KIIs with diverse community members, including EVD survivors, healthcare workers, and religious leaders, the study captured a range of perspectives that reflect both individual experiences and broader systemic challenges.

Importantly, this research captured perceptions during the pre-licensure phase of Ebola vaccine deployment, offering a valuable baseline for future comparisons with licensed vaccine dose delivery and other vaccines deployed during the pre-licensure phase. As such, the findings not only illuminate key barriers and drivers at a critical historical moment but also lay the groundwork for understanding how perceptions may shift in response to changes in policy, delivery strategies, and levels of institutional trust.

Overall, the study reinforces the need for sustained and community-centered engagement strategies, transparent and balanced communication, integration of trusted local actors in planning and implementation for vaccine delivery, and the tailoring of public health messages to address deeply rooted concerns. Future vaccination campaigns, particularly in conflict-affected or low-trust settings, must go beyond biomedical considerations and actively engage with the social, political, and cultural contexts that shape community decision-making. In doing so, they will be better positioned to build lasting trust, counter misinformation, and support equitable access to life-saving vaccines.

Supporting information

Acknowledgments

The authors acknowledge the invaluable contributions of the participants and local communities in sharing their insights, which have contributed significantly to our understanding of vaccine hesitancy in the context of EVD outbreaks, as well as to the research team and International Medical Corps staff for their contributions to this study.