Qualitative exploration of COVID-19 vaccine uptake among healthcare workers in Sierra Leone: do the ‘trusted messengers’ trust the vaccine?

Abstract

Introduction

Vaccine hesitancy is a global issue, and the important role of healthcare workers in addressing vaccine hesitancy is well documented. However, there is limited theory-guided research on the uptake of COVID-19 vaccinations among healthcare workers in low- and middle-income countries (LMICs). This study examined COVID-19 vaccine uptake among healthcare workers in Sierra Leone and assessed the relevance of the 5C model—which posits that vaccine uptake is shaped by confidence, complacency, constraints, calculation and collective responsibility—in explaining their vaccination attitudes, intentions and behaviours.

Methods

24 indepth interviews were conducted in 2022 with healthcare workers in Freetown, Makeni and Kenema. The resulting narratives were thematically analysed to identify factors that promoted or deterred COVID-19 vaccination.

Findings

Key facilitators of COVID-19 vaccine uptake included positive views on adult vaccines, self-protection and the desire to be role models. Major barriers were complacency, distrust in available vaccines and safety concerns. Additionally, participants’ perspectives were informed by their experiences with the Ebola outbreak, indicating that prior epidemic memory influenced how the 5C domains were interpreted and operationalised in relation to vaccine uptake in contexts such as Sierra Leone.

Conclusions

This paper examines social determinants of vaccine uptake and offers policy recommendations to enhance vaccine uptake among trusted messengers in the region, thereby supporting global COVID-19 recovery and improving LMIC preparedness for future outbreaks. Future responses to public health emergencies in LMICs should be informed by local contextual experiences, and vaccine programmes must consider these factors during planning and implementation.

WHAT IS ALREADY KNOWN ON THIS TOPIC

• Vaccine hesitancy is a global issue influenced by factors related to confidence, complacency, constraints, calculation and collective responsibility (5Cs).

WHAT THIS STUDY ADDS

• In low-income settings, prior experiences with outbreaks influence healthcare workers’ vaccine decisions, highlighting vaccine uptake as both a cognitive and emotional process.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

• Global preparedness for future infectious disease outbreaks necessitates nuanced, context-specific interventions that address vaccine hesitancy in low-income settings while considering complex social and emotional dynamics.

Introduction

The uptake of COVID-19 vaccines by healthcare workers is vital for enhancing public confidence in vaccination.^{1 2} Healthcare workers are perceived as reliable sources of health information and play a significant role in vaccine decision-making.² The existing literature suggests that the recommendation of a healthcare provider is the most important predictor of vaccination for many individuals.^{3 4} Consequently, as well as due to their high risk of exposure to COVID-19, healthcare workers were given priority for early vaccination when limited doses of the vaccine were initially available.^{5 6} This prioritisation was in accordance with the recommendations of both the Advisory Committee on Immunization Practices and the WHO.^{7 8}

As role models in their communities, healthcare workers can greatly influence public uptake and recommendation of the COVID-19 vaccine.^{9 10} Their influence in guiding vaccination decisions, addressing hesitancy and disseminating information about risks and benefits has been demonstrated globally.^{11 12} Healthcare workers are also responsible for prescribing and administering COVID-19 vaccines and are major determinants of patient vaccine acceptance and uptake, which impact herd immunity.^{4 12 13} The quality and dissemination of information by trusted healthcare workers are crucial to improving public acceptance and knowledge about vaccines, as individuals often rely on them for making informed health decisions.^{14 15} Healthcare workers, thus, play a pivotal role in building public trust and promoting vaccine uptake through the provision of accurate and reliable information.14,16 Hence, widespread COVID-19 vaccine acceptance by healthcare workers may enhance public acceptance, as they are more likely to recommend vaccination to patients, family and friends, ultimately promoting health and saving lives.^{2 14 17}

The existing literature suggests that COVID-19 vaccine hesitancy among healthcare workers is not uncommon. Studies conducted globally before COVID-19 vaccines were available and in the early vaccine rollout periods suggest healthcare workers’ varying levels of willingness to get vaccinated. For example, in Africa, willingness ranged from 27.7% in Congo to 90.1% in South Africa, averaging 63% from meta-analytic reviews.¹⁸ These rates are not unique to Africa; in France, only 75% of healthcare workers reported willingness to be vaccinated before vaccine availability, while a similar Canadian study conducted during the initial rollout recorded 80%.^{10 19} In the USA, a study conducted before vaccine availability found only 64% willingness among employees at two large Philadelphia hospitals, while a later study during early vaccine rollout reported 86% among emergency department healthcare workers at 20 urban medical centres across the USA.^{20 21} Vaccine acceptance in the general population mirrored rates among healthcare workers, as polling in 2020 showed that 74% of adults in 27 countries were willing to get the COVID-19 vaccine.²² These similar rates of vaccine uptake among healthcare workers and the general public reinforce the importance of healthcare workers as role models for healthy behaviours.^{21 23}

Sub-Saharan Africa experienced a relatively muted first COVID-19 wave in 2020, but later surges driven by the Delta (mid-2021) and Omicron (late-2021) variants saw sharp spikes in infections and hospitalisations.^{24 25} Sierra Leone mirrored this broader regional trend, with confirmed cases increasing in each successive wave.²⁶ However, limited testing capacity likely led to an underestimation of the true epidemiological burden.²⁶ Vaccination was rolled out nationally in early 2021, first with healthcare workers and other high-risk groups, and by mid-2023, about 73% of adults were fully vaccinated.²⁶ Sinopharm was the only COVID-19 vaccine available in Sierra Leone until March 2021, when the AstraZeneca-Oxford vaccine was introduced for public use.²⁷ This coincided with the period during which the AstraZeneca-Oxford vaccine was under global regulatory review following reports of rare but serious adverse events.^{28 29} Over time, the Sierra Leone population had access to four brands of the COVID-19 vaccine (Pfizer, Johnson & Johnson, AstraZeneca and Sinopharm), with Sinopharm being the most commonly offered product to individuals with no pre-existing health condition.³⁰ Global evidence suggests that COVID-19 vaccination sharply reduced healthcare workers’ infections and severe outcomes, lowered mortality in long-term care settings and demonstrated no increase in adverse events when co-administered with influenza vaccine.31,34 However, reports suggest that concerns about side effects, along with persistent misinformation and public misconceptions, continued to erode confidence in COVID-19 vaccination efforts in Sierra Leone.^{26 35 36} While robust evidence of safety highlights the COVID-19 vaccine’s potential, lingering doubts about side effects and misinformation suggest the need to understand how such concerns affect uptake, especially among healthcare workers.

Having experienced the Ebola outbreak in 2014 and now dealing with the COVID-19 pandemic, an understanding of healthcare workers’ attitudes towards vaccine uptake could be relevant in predicting their response to future pandemics and infectious disease outbreaks. The findings from this paper could also have relevance to other low and middle-income country (LMIC) settings that have now faced the challenges of COVID-19.

Conceptual framework

Vaccine acceptance is shaped by a range of psychological, contextual and structural factors. To better understand these drivers, researchers first introduced the 4C model, which identified four psychological antecedents of vaccination: confidence, complacency, constraints and calculation.³⁷ Building on this foundation, Betsch and colleagues later developed the 5C model (figure 1), adding collective responsibility to capture the prosocial motivation behind vaccination behaviour.³⁸ The 5C model has since become a widely used framework in vaccine psychology research, outlining five core determinants of vaccination behaviour: confidence (trust in vaccine safety, efficacy and health authorities), complacency (low perceived risk of disease), constraints (logistical or psychological barriers to vaccination), calculation (deliberation based on information-seeking, which may increase hesitancy when misinformation is encountered) and collective responsibility (motivation to protect others through herd immunity).39,42

Figure 1. The 5C model of vaccine hesitancy. This model outlines five key determinants of vaccine hesitancy: confidence, complacency, constraints (convenience), calculation and collective responsibility. Each factor represents a psychological driver influencing vaccination decisions.

Understanding how healthcare workers make decisions concerning COVID-19 vaccination has significant implications for public health, especially in preparing for future outbreaks. Hesitancy among this group can reduce public trust and further exacerbate vaccine hesitancy in the broader population. The Centers for Disease Control and Prevention (CDC) recommends the use of ‘trusted messengers’ as a promising approach to addressing vaccine hesitancy.⁴³ This paper aims to broaden understanding of COVID-19 vaccine uptake among healthcare workers in Sierra Leone by exploring factors that promote or deter vaccination and by examining the relevance of the 5C model in explaining attitudes, intentions and behaviours. While the 5C model remains a widely used framework to understand vaccine hesitancy, several studies have proposed adaptations to capture its limitations across different settings and populations. For instance, Geiger and colleagues introduced a 7C model by adding compliance and conspiracy, reflecting behavioural regulation and misinformation dynamics in Europe during the COVID-19 pandemic.⁴⁴ Similarly, a study involving both healthcare workers and the general public in France expanded the 5C model by incorporating system-level confidence and social conformity, identifying institutional trust and peer influence as distinct drivers of vaccine behaviour.⁴⁵ Another UK study emphasised the importance of an additional two Cs, contextual factors and communication in addressing vaccine hesitancy shaped by sociodemographic and informational disparities.⁴⁶ Although these expansions enhance the 5C framework by addressing contemporaneous social and structural influences, none have explicitly incorporated prior epidemic experiences as a determinant of vaccine behaviour. The relevance of the 5C framework to low-resource, postepidemic contexts has, therefore, received little empirical attention. This study extends the 5C framework by investigating how healthcare workers’ experiences with prior infectious disease outbreaks—particularly the 2014 Ebola epidemic—shape each of the model’s domains (confidence, complacency, constraints, calculation and collective responsibility). In this paper, we apply the 5C model within the context of epidemic memory, conceptualising prior outbreak experience as a cross-cutting contextual modifier—rather than a standalone determinant of vaccine behaviour—that reshapes confidence, complacency, constraints, calculation and collective responsibility. A companion manuscript from the same project examines the postvaccination experiences of these healthcare workers—focusing on adverse-event narratives, perceived protection and subsequent advocacy—using the Theory of Planned Behavior as its analytic lens.⁴⁷ The current manuscript addresses the decision-making phase that preceded vaccination and applies the 5C framework. Separating the two phases into distinct manuscripts allows each to offer deeper, theory-driven insights and avoids conflating pre-decision factors with postvaccination reflections.

Methods

Sample

This study’s qualitative data came from indepth interviews conducted with healthcare workers with clinical and public health roles in three regions hardest hit during the 2014 Ebola outbreak in Sierra Leone (Freetown, Makeni and Kenema). In early to mid-2022, participants were recruited via invitation messages on professional association groups on social media. Purposive sampling based on participants’ expressed interest following engagement at each regional hospital was employed and supplemented by snowball sampling techniques. The recruitment continued until data saturation was achieved—when no new themes or insights emerged from subsequent interviews.⁴⁸ The final sample included 24 healthcare workers (see table 1 for participant demographic information).

Table 1. Participant demographic information.

Gender	N	%
Female	17	70.8
Male	7	29.2
Age range
18–25 years	1	4.2
26–32 years	5	20.8
33–39 years	15	62.5
40–50 years	2	8.3
50+ years	1	4.2
Marital status
Single (never married)	9	37.5
Married	12	50
Widow	2	8.3
Single (divorced)	1	4.2
Health worker designation
Nurse	18	75
Doctor	4	16.7
Hygienist	1	4.2
Community Health Officer	1	4.2
Work location
Freetown	9	37.5
Kenema	8	33.3
Makeni	7	29.2
Years of experience
1–3 years	3	12.5
4–6 years	2	8.3
7–9 years	12	50*
>9 years	7	29.2*
COVID-19 vaccination status
Vaccinated	21	87.5
Unvaccinated	3	12.5

^*Participants who practiced as healthcare workers during the 2014–2016 Ebola outbreak.

Interviews

Interviews took place in person or via Zoom based on participant preferences and lasted around 35 min each. All interviews followed a semistructured guide (see online supplemental appendix A for complete interview guide). The first six interviews (with participants from Freetown) were conducted in February 2022, and the remaining sessions took place in June and July 2022 with participants from Makeni and Kenema. The interviews were conducted in English or Krio based on each participant’s preference and questions centred on various aspects of healthcare workers’ experiences during the COVID-19 pandemic and their decision-making on COVID-19 vaccine uptake. Responses to these prompts formed the basis of this analysis. Interviews were recorded and then fully transcribed/translated for analysis. Zoom recordings were captured with end-to-end encryption enabled; inperson sessions were recorded on an encrypted, password-protected digital recorder. All audio files were transferred within 24 hours to encrypted, access-restricted university server and deleted from the recording devices.

Data privacy

Participants were assigned a unique identification code. Identifying information was stored in a separate encrypted file accessible only to the principal investigator and managed in accordance with ethics committee approval.

Analysis

Thematic analysis was used to identify major patterns in the data in accordance with theme analysis protocol by Guest, MacQueen and Namey.⁴⁹ The data were reviewed, coded and interpreted using an iterative process as follows. The first six interviews were reviewed and examined for common themes and unique information. The unique information was incorporated into the interview prompt for the remaining 18 interviews. Once completed, these interviews were analysed for existing and emerging themes. A codebook was created defining each theme and it was used to code three interview transcripts selected at random. Coding cross-checking was conducted on these three transcripts by the lead author and one coauthor to ensure consistency in theme interpretation and code application. Once agreement was reached and a shared understanding of each code was established, the lead author independently coded the remaining transcripts. Frequent analytic meetings were held between the lead author and coauthors throughout the coding and analysis process. During these meetings, coauthors independently reviewed coded excerpts, provided feedback on theme definitions and challenged initial interpretations to ensure reflexivity and reduce the risk of thematic anchoring. Any disagreements about code application or theme boundaries were discussed until consensus was reached. This iterative process, combined with the initial double-coding of three transcripts, helped to establish a shared understanding of the coding framework and consistency in theme interpretation. After coding was completed, all coauthors reviewed the full coding framework and thematic structure in detail to confirm alignment between the final themes and the underlying coded data. The analysis was conducted in ATLAS.ti, where deidentified transcripts were uploaded to the platform, which supports two-factor authentication. Access was restricted to the core analytic team.

This paper specifically focuses on data related to COVID-19 vaccine uptake decision-making. A specific round of coding was performed using the process outlined above (defining subthemes, creating a codebook, coding and reviewing) to identify subthemes related to COVID-19 vaccine uptake that are outlined in the findings section.

Researcher positionality and reflexivity

All interviews were conducted by the first author, a Sierra Leonean clinician who provided care during the 2014 Ebola outbreak. The interviewer’s insider status may have facilitated rapport and disclosure, but it could also have introduced social-desirability or confirmation bias. To minimise bias in the data analysis, two coauthors who were not involved in data collection and did not share the same professional background independently reviewed the transcripts, validated the codebook and resolved discrepancies through peer debriefing.

Patient and public involvement

The healthcare worker population participated in distributing the project’s recruitment flyers and feedback from the first six participants was used to refine the indepth interview guide (online supplemental appendix A) for subsequent data collection.

Findings

The study examined both healthcare workers’ attitudes toward the COVID-19 vaccine and their decision-making regarding vaccine uptake. Thematic analysis was guided by the 5C model of vaccine hesitancy—confidence, complacency, constraints, calculation and collective responsibility—with an additional theme, Epidemic memory as a contextual modifier of the 5Cs, emerging as a contextual lens that influenced participants’ responses across all domains. This experiential component played a major role in the healthcare workers’ decision-making process, adding a significant layer of context to the established 5C model. The findings are presented with participant ID numbers, gender identity and healthcare roles; however, the analysis did not uncover meaningful differences across these categories. While the thematic structure aligns with the five domains of the 5C framework, participants’ narratives frequently traversed distinct decision-making levels—personal uptake, professional responsibilities as health communicators and perceptions of community hesitancy. These domains often overlapped, reflecting the entangled nature of individual experience, professional identity and social context in this setting. Analytically, we also distinguish between healthcare workers’ personal vaccination decisions, their professional role as trusted messengers and their perceptions of population-level hesitancy (see online supplemental appendix B for relevant quotes).

Confidence

Healthcare workers’ confidence in the COVID-19 vaccine was shaped by their perception of other vaccines as well as the available COVID-19 vaccine. Participants’ experiences with infectious diseases in the region had positively influenced the acceptance of vaccines. Healthcare workers demonstrated a general knowledge of what vaccines typically do, why getting vaccinated is important and their general willingness to vaccinate against infectious diseases. However, unique factors influenced views on the COVID-19 vaccine, such that confidence was more mixed than for other vaccines. This theme explores healthcare workers’ trust in the COVID-19 vaccine, specific vaccine brands and health authorities.

In discussing their personal vaccination decisions, participants expressed a lack of confidence in the available COVID-19 vaccines, particularly the Sinopharm vaccine, due to insufficient information about its trial process. Some believed that the vaccine had not yet been approved for public distribution, but was being tested on the Sierra Leonean population, reducing their trust in the safety of the vaccine.

My belief about the vaccine is that it’s still experimental. Receiving it doesn’t prevent you from testing positive for COVID in the future. I’m an example of this—I tested positive even after getting two doses of the Sinopharm vaccine. For me, it’s still a trial vaccine. (P02, Male nurse)

While he got the vaccine as he was desperate to protect himself, his subsequent infection with COVID-19 reinforced his pre-existing doubts about the Sinopharm vaccine.

AstraZeneca, another vaccine regimen that garnered enormous controversy regarding safety during its early rollout, was made available shortly after the Sinopharm vaccine rollout commenced. One male doctor explained his thoughts about the available vaccines, “There were two vaccines at the time, and these were AstraZeneca and Sinopharm. I was more confident in the AstraZeneca than the Sinopharm” (P07). When asked about his reasons, this doctor said,

Honestly, I was hesitant about a Chinese-made vaccine. There have been numerous conspiracy theories surrounding COVID vaccines, particularly about alterations to our genetic makeup. While I trusted other vaccines, I couldn’t bring myself to trust the Chinese vaccine due to a lack of sufficient information about it. (P07, Male doctor)

Participants expressed doubts about the viability of the vaccines provided to Sierra Leone by Western countries. Rumours spread that the doses of AstraZeneca supplied to Sierra Leone were only released by the donors when their expiry dates were close. One participant shared their views reflecting on their professional roles as health workers and views on population-level hesitancy.

It’s important for people to take the COVID-19 vaccine provided that the vaccines are not expired. I’ve already taken my complete dose but there has been reliable information that the current vaccines available are expired, hence, I’ve even been advising people to stop taking them until new stocks are available. (P06, Female nurse)

This belief that the majority of such doses were expired by the time they were being distributed in Sierra Leone further dampened health workers’ confidence in them, even though many viewed AstraZeneca as the better of the two options. Ultimately, confidence—or lack thereof—played a critical role in shaping whether healthcare workers chose to receive the vaccine, particularly when information gaps or mistrust of specific vaccine brands existed.

Calculation

Healthcare workers in Sierra Leone weighed their risks of COVID-19 exposure and infection against potential vaccine side effects when deciding on vaccination uptake. Of the 24 participants, the majority (21) were vaccinated, some immediately after the vaccine was available and others after a period of deliberation.

The influence of media coverage on their risk perception was substantial. Reports of deaths and severe illness from COVID-19 globally made healthcare workers particularly fearful, especially those in high-risk clinical roles within COVID-19 isolation and treatment units. One nurse discussed their personal vaccination decision as follows,

When it (referring to the COVID-19 vaccine) was available at our hospital, I took it immediately because I wanted to protect myself. Based on the things we’ve heard in the news in Western countries, I was afraid of getting infected. (P22, Female nurse)

She highlighted her role in an isolation centre as a key factor in her decision, emphasising the dual benefits of personal protection and preventing transmission to her family,

Because I was working in the isolation centr, I knew my risk of contracting COVID-19 was significantly higher without the vaccine. I was there every day, interacting with potentially COVID-19-positive patients, and I was concerned about getting infected and then transmitting the virus to my family members at home. (P22, Female nurse)

Hence, the perception of risk and a desire to protect oneself, as well as loved ones, were key calculations healthcare workers made as they considered COVID-19 vaccine uptake.

Despite the general acceptance of the vaccine by the study population, calculation of adverse effects and vaccine efficacy led some participants to delay or avoid vaccination. Reported side effects and conspiracy theories contributed to hesitancy. For instance, a male doctor explained their views on population-level hesitancy and its impact on their personal vaccination decision.

Even with my knowledge as a healthcare worker, those concerns contributed to my hesitation in getting vaccinated. Most of the people around me were worried and advised against taking the vaccine due to fear of its side effects. I believe this fear is a problem, as those who are not getting vaccinated are influencing others by spreading fear. (P20, Male doctor)

In some instances, the fear of adverse effects was grounded in scientific evidence of typical symptoms experienced after COVID-19 vaccination. This concern was highlighted as a major personal reason for opting out of vaccination, as described by another participant, “I’m afraid of the side effects of the vaccine, especially getting sick. I don’t want to go through that” (P21, Female nurse).

Concerns about the vaccine’s effectiveness, especially against different COVID-19 strains, also fueled scepticism. A public health worker noted their personal concerns.

Honestly, I have reservations about the vaccine. Given the emergence of various strains of the coronavirus, I am highly sceptical about the available vaccines’ ability to protect against one or more strains. I was uncertain about the vaccine’s effectiveness, which is why I hesitated to get vaccinated. Additionally, the information provided about the vaccine has been vague regarding its protection against specific strains. (P20, Female public health worker).

These narratives illustrate the complex calculations healthcare workers performed—balancing personal and community protection against perceived risks and misinformation—as they considered COVID-19 vaccine uptake.

Complacency

Some participants were complacent about their need for the COVID-19 vaccination, largely reflecting their personal vaccination decisions. Natural immunity was thought to be a more reliable protection strategy than COVID-19 vaccines. This was especially true for one of our participants who got the vaccine but was not convinced that it was needed. He believed that respiratory viral vaccines are usually less effective and cited the influenza vaccine as an example. Hence, natural immunity was preferred to COVID-19 vaccination.

I took the vaccine for protection but I’m not sure it’s a great deal of protection. I think, I just don’t want to be blamed if I get ill with COVID in the future. Mostly to satisfy my conscience that I’ve done my best. I don’t think respiratory vaccines are effective and the influenza is an example. Another main reason is that I don’t want to be deprived of opportunities because of not getting the vaccine. (P20, Male doctor).

He eventually received the COVID-19 vaccine due to social pressure, not because he was convinced of its necessity.

Participants also saw diligent adherence to COVID-19 prevention practices as sufficient protection, making vaccination unnecessary. At the time of the interview, a nurse felt she did not need the vaccine, “I don’t see a need for getting it when I can just keep using the preventive measures” (P21, Female nurse).

Even though she did not see the value of getting vaccinated at the time, she acknowledges that her stance may change in the future if circumstances dictate it. The COVID-19 vaccine was viewed as new, with low levels of information on safety and efficacy. Complacency, rooted in beliefs about natural immunity, low personal risk and reliance on other preventive measures, influenced some participants to delay vaccination or question its necessity despite general awareness of COVID-19 risks.

Constraints

A key constraint to COVID-19 vaccine uptake among healthcare workers in Sierra Leone was the limited vaccine types, especially during early rollout. The vaccines available in Sierra Leone were limited and different from those in high-income countries, and often individuals were not offered a choice of which vaccine to receive.

In Sierra Leone, the Pfizer and Moderna vaccines, which were believed to have superior safety and efficacy profiles compared with the available Sinopharm vaccine, were not available. When asked about her thoughts on public data from the CDC and the USA on vaccine safety, a nurse was quick to share her personal vaccine thoughts, “We can’t compare our situation with the USA; it is different. Also, by the time the vaccines get to us, we’re not sure if they are still viable to take” (P06, Female nurse).

Healthcare workers expressed doubts about the safety and efficacy of the vaccines distributed in Sierra Leone and were hesitant to take the vaccine. A female public health nurse shared her personal reflections on vaccine hesitancy alongside broader observations regarding population-level hesitancy.

Well, we do not like the available vaccines I guess, but also, everyone is suspicious that the vaccine we are receiving is different from the one that is being given in Western countries. So, people have doubts. Even when the president took the vaccine, people claimed that he might have been given the original version of the vaccine while the rest of the population would be given a different version. So, there is a lot of doubt. (P21, Female nurse)

Healthcare workers’ doubts about the quality of the COVID-19 vaccines distributed in Sierra Leone, especially compared with high-income countries, constrained their choices and thus their willingness to take up the vaccine.

In addition to having only two vaccine options (Sinopharm and AstraZeneca) during the early stages of vaccine distribution in Sierra Leone, individuals were not given the opportunity to choose which of those vaccines to take. The decision was made by the vaccinators based on reported age and the existence of underlying health conditions. Young persons and those not reporting any underlying conditions were given the Sinopharm vaccine while older persons and those with underlying conditions were given the AstraZeneca vaccine.⁵⁰ The rationale for this practice could not be explained by any of the healthcare workers interviewed (including medical doctors), thus casting further doubts on the vaccine distribution process. A male medical doctor speculated on this practice,

Well, the reason was not clear and was not explained. However, it looked like the health authorities were more confident about the safety of AstraZeneca than that of Sinopharm. So maybe that’s why they were not very clear about the reasoning. (P23, Male doctor)

A female nurse also shared her personal experiences of this practice,

I wasn’t even aware of other vaccine options. The vaccinators simply asked about my health condition and then decided which type I should receive. I only found out which vaccine I was given when I looked at the card they provided. (P10, Female nurse)

Her emphasis on her lack of choice—only knowing which vaccine she received when she was handed her card—highlights the reality of this constraint.

Collective responsibility

Healthcare workers demonstrated a sense of collective responsibility as they expressed their commitment to protecting themselves, other health professionals and others in their community. The study participants saw themselves as trusted sources of health information. They believed that their opinions about and actions related to COVID-19 vaccination were among the things shaping public acceptance.

Some healthcare workers saw their personal vaccine uptake decision as influential to others’ decision-making process given their professional roles. A medical doctor explains,

I received two doses of the vaccine and was among the first to be vaccinated. As the coordinator when the vaccination process began at the hospital, I needed to lead by example. So, I was the first to get vaccinated, and all other staff members witnessed my actions. However, my primary reason for getting the vaccine wasn't just to set an example; I wanted to protect myself. (P07, Male doctor)

While he was keen to protect himself as well as others, his decision to vaccinate early further reinforces his role as a trusted messenger.

Healthcare professionals also saw themselves as role models in their homes and communities, contributing to a collective responsibility for vaccine uptake. Two female nurses described their COVID-19 vaccine uptake decisions as shaped by both personal choice and perceived professional obligation, “I took the COVID-19 vaccine to protect myself and also to sensitise and give confidence to my loved ones that the vaccine is good” (P17, Female nurse). Another said, “As health workers, we had to take the lead” (P10, Female nurse). Acknowledging their roles in building COVID-19 vaccine trust in their communities, healthcare workers recognised that their own vaccine uptake decision was crucial.

Epidemic memory as a contextual modifier of the 5Cs 

In addition to the 5Cs, prior epidemic experience (epidemic memory) emerged as a theme. A recurring theme in discussions was the impact of the Ebola outbreak on vaccine confidence. Despite facing challenges such as low confidence in the COVID-19 vaccine, most healthcare workers, having witnessed the devastating consequences of Ebola without a vaccine, chose to get vaccinated. When asked why she got vaccinated despite low confidence in the vaccine, a participant shared their personal decision-making.

To prevent myself from getting COVID-19, because, during the Ebola outbreak, we did not have a vaccine, and hence many lives were lost, which would not have been the case if there was a vaccine. (P04, Female, nurse)

Another healthcare worker who had previously worked in the Ebola treatment unit echoed a similar sentiment.

During the Ebola outbreak, people were dying all the time … I just felt vulnerable as a health worker, and I wanted to protect myself. My decision had nothing to do with the advertisements. I was among the first group of people to take the vaccine. (P02, Male nurse)

Thus, epidemic memory tempered the influence of low confidence in a way that led to higher vaccination uptake than might be expected given this level of confidence in available vaccines.

The calculation involved in the decision-making process also bears the imprint of Ebola. Healthcare workers’ experiences of vulnerability during the outbreak guided their choices and echoed in the ways they spoke about their vaccination decisions. Participants mainly accepted the COVID-19 vaccine to protect themselves, a personal decision underscored by narratives of self-preservation: “Because I was afraid of the COVID-19 illness, and I wanted to protect myself” (P12, Female nurse) and “Because I want to protect myself and be well” (P16, Female hygienist). These participants were vaccinated early to protect themselves as they felt similar fear and vulnerability that they had experienced during Ebola returning with the emergence of COVID-19, as reported in their descriptions of Ebola experiences: “Ebola was very scary…. even at our houses, if you are a health worker and you are renting, you will be evicted by the landlord during the Ebola outbreak people were very very scared” (P16, Female hygienist); “the Ebola outbreak was worse” (P12, Female nurse). The comparative severity of COVID-19 and Ebola also seemed to influence levels of complacency. Hence, while some healthcare workers felt vulnerable, others seemed to sense that COVID-19, particularly in Sierra Leone, was not as severe as Ebola had been. A participant shared both their personal views and their perceptions of vaccine hesitancy at the population level.

With the Ebola, even when the vaccines were under trial, people were rushing to get it. Ebola was more dangerous. This one [COVID-19] is just different, and no one is advising each other to get the vaccine. Rather we’re taking the prevention measures seriously (P21, Female nurse).

These comparisons suggest that epidemic memory may not uniformly increase vaccine uptake; rather, it operates through comparative risk appraisal, sometimes amplifying and sometimes dampening perceived need depending on how the new threat is evaluated relative to past outbreaks.

As noted above, despite limited choices and other constraints, the majority of healthcare workers reflected on their past experiences with Ebola, leading them to get the COVID-19 vaccine soon after it became available to protect themselves and others; “We were eagerly awaiting the vaccine’s arrival so when it was available, we took it to protect ourselves” (P04, female nurse). When asked about their experiences with COVID-19 prior to vaccination, this participant had reported the following: “I was afraid especially when I reflect back on the past Ebola outbreak” (P04, female nurse). The collective responsibility to vaccination, despite the constraints, signifies a broader recognition of ways that healthcare workers must signal to others the importance of immunisation.

In summary, the participants’ recent experiences with the Ebola outbreak were pivotal in shaping their responses to the COVID-19 vaccine. The Ebola outbreak functioned as a form of epidemic memory that recalibrated how healthcare workers interpreted each of the 5Cs, often explaining vaccine uptake even in the presence of low confidence or high uncertainty. In a setting where vaccine information dissemination efforts left so many unanswered questions, prior experiences with Ebola impacted vaccine uptake decisions among the study participants. Integrating an understanding of how past experiences shape the 5Cs offers a richer perspective on vaccine uptake.

Discussion

This study aimed to explore COVID-19 vaccine uptake among healthcare workers in Sierra Leone, identifying the facilitators and barriers to vaccine uptake. Healthcare workers discussed their experiences of vaccine uptake in terms of their perceptions of other adult vaccines, wanting to protect oneself and a desire to set examples for others recognising their role as ‘trusted messengers’. Online supplemental appendix B presents a domain-level analytic mapping of all quotations included in the findings, distinguishing between personal vaccination decisions, professional trusted-messenger roles and perceptions of population-level hesitancy. Conversely, complacency, distrust for vaccine regimens available in Sierra Leone and concerns about safety and efficacy emerged as key barriers to vaccine uptake. Importantly, while the 5Cs provided a strong framework for understanding the experience of these healthcare workers, their past experiences with infectious disease outbreaks impacted each of these factors.

Given that their healthcare roles heightened their exposure risk to COVID-19,^{51 52} the decision to postpone vaccine uptake could have proven to be a costly one. Similar to other studies, healthcare workers who felt vulnerable to infection, particularly in our study those working in COVID-19 isolation and treatment units, were motivated to get vaccinated by the desire to protect themselves and their patients.⁵³ Healthcare workers believed that their uptake of the vaccine would encourage other members of their household, patients and communities to take the vaccine. This notion of collective responsibility underscored the importance of healthcare workers as role models and trusted messengers in promoting vaccine uptake among their communities (CDC,⁴³). Participants’ accounts also suggested that their role as ‘trusted messengers’ operated both as a motivator for vaccine uptake and, in some cases, as a retrospective justification for their decisions. This duality appeared to be shaped by a combination of internal values, institutional expectations and prevailing social norms. Participants, therefore, frequently described balancing self-protection with a sense of altruistic or professional responsibility, illustrating how individual risk perceptions and collective obligations coexisted in shaping vaccine decisions.

Complacency emerged as a barrier to vaccine uptake as some healthcare workers preferred natural immunity and prevention behaviours to COVID-19 vaccine uptake. This finding is consistent with previous research on vaccine hesitancy, where perceptions of low risk are a common reason for vaccine hesitancy.^{23 54} Distrust and concerns about the safety and efficacy of the available vaccine regimens in Sierra Leone were also a deterrent for COVID-19 vaccine uptake. Following a decade-long civil war in Sierra Leone that was fuelled by considerable international support for violence in exchange for natural resources such as diamonds,^{55 56} people are not always trusting of international ‘assistance’. As a result, the authenticity of global assistance in supplying healthcare products is frequently scrutinised and examined in comparison to what is offered in high-income contexts.⁵⁷ The Sierra Leonean population only had access to Sinopharm and AstraZeneca, both with questionable safety and efficacy profiles at the time due to limited research literature and reports of adverse events.58,60 Even worse, news reports that the COVID-19 vaccine doses donated to Sierra Leone only had a few weeks of shelf-life before expiration did not engender confidence.⁶¹ However, these factors do not explain the observed pattern of vaccine uptake. Epidemic memory provides the missing explanatory link by clarifying how healthcare workers prioritised action despite uncertainty, drawing on prior experiences of loss, vulnerability and institutional inadequacies.

Applying the 5C model in contexts shaped by epidemic memory

The findings of this study not only support the constructs of the 5C model of vaccine hesitancy but also emphasise the substantial influence of contextual experiences on individuals’ decisions regarding vaccine uptake (figure 2). Most of the study participants had healthcare roles during the 2014 Ebola outbreak, which shaped their perceptions of risk, severity and vaccine benefits. Discussions among the participants revealed that their experiences during both the Ebola outbreak and the ongoing COVID-19 pandemic had an impact on their viewpoints regarding vaccine facilitators and barriers.

Figure 2. The 5C model applied under conditions of epidemic memory in Sierra Leone. An adaptation of the 5C model, Epidemic memory operates as a contextual overlay shaping all five domains, rather than as an additional construct. This includes personal and collective experiences with Ebola, COVID-19 and broader historical and health system-related events.

Aligned with the 5C model of vaccine hesitancy, healthcare workers drew comparisons between the Ebola and COVID-19 outbreaks, considering aspects of vaccine confidence, complacency, calculation, convenience and collective responsibility. Their firsthand encounters with disease outbreak severity, coupled with the portrayal of COVID-19’s expected severity by the media, influenced their motivation for COVID-19 prevention and vaccine acceptance.

While the 5C model of vaccine hesitancy provides valuable insights into the factors driving individual vaccine decisions, it was primarily developed based on research conducted in high-income settings, where confidence and complacency issues play a prominent role in vaccine hesitancy.38,42 However, in low-resource settings like Sierra Leone, where previous experiences with infectious diseases and healthcare systems are significant, the 5C model may not capture the full complexity of vaccine hesitancy. The study findings suggest that the decision-making process regarding vaccine uptake was not solely influenced by the constructs of the 5C model but also by participants’ prior encounters with infectious disease outbreaks. Furthermore, the study participants reported that their experiences with the Ebola outbreak substantially shaped their perceptions towards disease prevention, enhanced their understanding of infectious diseases and contributed to their knowledge in this area. The findings suggest that vaccine hesitancy in low-resource settings is not solely a cognitive process but also an emotional and social one, shaped by personal and collective histories of survival, resilience and commitment to safer health practices. As a result, the study demonstrates that prior outbreak exposure (epidemic memory) operates as a cross-cutting contextual modifying factor that reshapes how confidence, complacency, constraints, calculation and collective responsibility are interpreted and enacted.

Prior outbreak experience has been shown to influence vaccine attitudes in some contexts, with studies reporting increased willingness among healthcare workers familiar with Middle East Respiratory Syndrome or Ebola vaccination efforts.^{62 63} However, other research findings from SARS and H1N1 influenza-affected settings suggest that prior exposure alone does not consistently translate into higher vaccine uptake, particularly when concerns about safety and trust persist.64,66 In Sierra Leone, historical institutional trust, geopolitical legacies and epidemic memory are critical contextual factors that intersect with the traditional 5C domains.^{67 68} While the traditional 5Cs provide insight into vaccine decision-making, participants’ narratives suggest that prior epidemic experience (epidemic memory) functioned as an interpretive lens through which each of the 5C domains was understood. In this analysis, epidemic memory (E) is conceptualised as the lasting, embodied, and socially shared interpretations of risk, responsibility and response shaped by health workers’ prior outbreak experiences, including perceptions of vulnerability, expectations of institutional performance and moral narratives of duty and survival. Epidemic memory is therefore operationalised as a temporal mechanism that shapes how new epidemic threats and interventions are interpreted in relation to the 5C domains. Our analytic 5C+E framework introduces experiences as a critical cross-cutting nuance, capturing the emotional, cognitive and social imprint of prior epidemic exposure—particularly relevant in low-resource settings shaped by recurring infectious disease outbreaks. This framework was pivotal in illuminating the paradoxical vaccine uptake observed in our study, where healthcare workers accepted vaccines despite low confidence in their efficacy and safety. Unlike prior modifications focused on present-day beliefs or systemic trust, the inclusion of epidemic memory adds a temporal dimension to the model, acknowledging how personal and collective histories shape vaccine decisions. Our findings suggest that epidemic memory operates through three interrelated processes: recalibrating perceived risk and vulnerability, shaping expectations of institutional trustworthiness and reinforcing moral narratives of professional responsibility. Through these processes, healthcare workers assessed COVID-19 vaccines not only as biomedical products but as tools for avoiding a repetition of past catastrophe. Existing anthropologic literature supports this notion as researchers found that preparation for COVID-19 in Sierra Leone was similarly shaped by ‘embodied epidemic memory’.⁶⁹

By incorporating epidemic memory into the existing 5C model, the framework better reflects the diverse reality of vaccine hesitancy in the region. This modification allows for more nuanced and context-specific interventions to address vaccine hesitancy and promote vaccine acceptance in low-income settings.

Conclusion and recommendation

The study highlights the importance of understanding facilitators and barriers to COVID-19 vaccine uptake among healthcare workers in low-income settings such as Sierra Leone. The findings also underscore the importance of addressing vaccine hesitancy and promoting vaccine confidence and trust to improve vaccine uptake. Furthermore, the study highlights the importance of understanding how past experiences with infectious diseases and vaccinations are likely to influence future vaccine decision-making. While vaccine hesitancy can be disease-specific, participants in this study frequently drew on their Ebola outbreak experiences when discussing COVID-19 vaccine decisions. These reflections may not imply a direct transfer of trust between or across vaccines, but rather reveal how prior epidemic exposure shaped perceptions of risk, urgency and institutional response—factors that informed their COVID-19 vaccination choices.

To increase COVID-19 vaccine uptake among healthcare workers in low-income settings, there is a need to: (1) address vaccine complacency through education and awareness campaigns that highlight the severity of COVID-19 and the potential for serious health consequences; (2) address concerns about vaccine safety and efficacy through clear and transparent communication about the safety and effectiveness of available vaccines, including dispelling common myths and conspiracy theories; (3) address distrust of vaccine regimens available in the region by ensuring that healthcare workers have adequate information and that donor agencies understand the importance of maintaining quality when distributing pharmaceutical products to low-income settings; (4) encourage healthcare workers to continue to set an example for others by taking the vaccine themselves and sharing their positive experiences with their colleagues, patients and communities; (5) continue to explore and evaluate vaccine uptake among healthcare workers in Sierra Leone to identify and address any ongoing barriers to vaccine acceptance; (6) further explore the role of the 2014 Ebola outbreak experiences on healthcare worker perceptions of infectious disease prevention and public health emergency response. In addition to these strategies, evidence from other settings demonstrates that brief dialogue-based training, structured reminder/recall systems and easily accessible workplace-based vaccination clinics can significantly increase healthcare worker vaccination rates.^{70 71} Adopting this integrated approach could similarly enhance booster and updated dose uptake among Sierra Leone’s frontline workforce. Future global response to public health emergencies in low-income settings should therefore be grounded in knowledge of unique local contextual experiences. Considering these factors during the planning of vaccine campaigns is essential to ensure the effectiveness of such interventions.

Given the research methodology, the findings from this study may not be applicable beyond similar low- and middle-income contexts, particularly those with recent epidemic exposure or histories of international health assistance. Hence, the 5C+E framework may be more relevant to LMICs with comparable epidemic legacies, such as Ebola. Additionally, although the sample included healthcare workers from three regions and varied professional roles, most participants were young and had received a COVID-19 vaccine. This may limit the diversity of perspectives captured, particularly among older or unvaccinated healthcare workers. Future research should explore the model’s relevance across more diverse demographic and experiential groups.

Data availability statement

Data are available upon reasonable request.