Predictors of malaria vaccine acceptability among healthcare providers in conflict-affected Sudan: a cross-sectional analysis

Abstract

Background

In October 2024, Sudan introduced the malaria vaccine, beginning in Al-Qadarif and Blue Nile states amidst an ongoing armed conflict. Vaccine acceptance among healthcare providers (HCPs) is critical for a successful national rollout. This study assessed malaria vaccine knowledge, acceptability, concerns, and their independent predictors among HCPs in these conflict-affected regions.

Methods

A descriptive cross-sectional study was conducted from January to February 2025 et al.-Qadarif and Al-Damazin teaching hospitals. An online questionnaire was administered to 342 HCPs. Multivariable linear regression was employed to identify factors associated with continuous knowledge scores. Subsequently, a multivariable logistic regression model was utilized to determine the independent predictors of high vaccine acceptability, incorporating the knowledge score as a continuous independent variable.

Results

Among the 342 respondents, general vaccine acceptability was promising, yet specific operational knowledge remained limited. Significant overall concern about the vaccine was prevalent (64.0%), primarily regarding adverse effects (57.0%), cold-chain handling conditions in Sudan (56.4%), and vaccine effectiveness (42.7%). Social media (48.5%) and peers (45.0%) were the most common information sources. Multivariable linear regression indicated that older age (p = 0.004)and hospital of work (p < 0.001) significantly predicted higher knowledge. In the multivariable logistic regression, the continuous knowledge score emerged as the only statistically significant independent predictor in this model of high vaccine acceptability (adjusted odds ratio: 1.15, 95% confidence interval: 1.01–1.32, p = 0.033), with no significant influence from demographic variables.

Conclusions

Despite a generally favorable attitude toward the malaria vaccine, Sudanese HCPs exhibit critical knowledge gaps and valid systemic concerns. Our findings suggest a sequential pathway wherein accumulated clinical experience (older age) enhances technical knowledge, which in turn acts as the primary independent driver of vaccine acceptability. Consequently, health authorities must pivot from generalized promotional campaigns to targeted, technical educational interventions. Leveraging secure digital professional networks is urgently needed to bridge these knowledge gaps, optimize provider confidence, and ensure a successful vaccine rollout in this fragile setting.

Trial registration Not applicable.

Supplementary Information

The online version contains supplementary material available at https://doi.org/10.1186/s12936-026-06031-7.

Background

Despite global control efforts, malaria remains a significant global health threat, ranking as the ninth leading cause of disease burden [1] and continuing to cause high mortality and disability, particularly in regions with limited access to effective prevention and treatment [2]. Africa bears the highest malaria burden worldwide, accounting for 94% of the global cases and deaths [3]. Data from the World Health Organization (WHO) World Malaria Report 2023 reported a decline in the number of malaria cases in the Eastern Mediterranean Region (EMR) before a 92% surge in 2022, reaching 8.3 million cases. The leading contributor to malaria in this region is Sudan, accounting for 41% of cases and the majority of regional deaths, with approximately 90% of infections caused by the severe Plasmodium falciparum strain [4].

​Since April 2023, Sudan’s health system has suffered extremely due to the armed conflict, which has displaced millions, severely damaged healthcare infrastructure, and significantly increased communicable disease outbreaks [5, 6]. The collapse has been particularly severe, with an estimated 70–80% of health facilities rendered non-functional, especially in conflict hotspots [7, 8]. Consequently, malaria incidence is increasing rapidly, particularly among internally displaced persons [6], with children under five remaining the most vulnerable demographic [9]. Notably, Al-Qadarif and Blue Nile states are among the highest malaria-burden areas in Sudan. Although multiple prevention strategies exist, their overall effectiveness remains hindered by inadequate resources, making the introduction of a malaria vaccine an exceptionally promising intervention [2]. In October 2024, Sudan became the first country in the EMR to introduce the malaria vaccine, receiving an initial batch of 186,000 doses specifically deployed to Al-Qadarif and Blue Nile states [10].

​However, the success of this historic rollout faces unique challenges within this fragile setting. Routine immunization is frequently hampered by logistical barriers, while public hesitancy toward novel vaccines poses a significant obstacle, as observed in recent studies among caregivers in Ethiopia and Nigeria which highlighted critical gaps in malaria vaccine acceptance [11, 12]. Understanding the drivers of such acceptance is often guided by established behavioral frameworks like the Health Belief Model (HBM), which posits that health behaviors are shaped by perceived susceptibility, severity, benefits, and barriers [13, 14]. Paradoxically, the collapse of environmental health services during the Sudan conflict has heightened the public's perceived susceptibility to vector-borne diseases. Within the HBM framework, healthcare providers (HCPs) serve as critical ‘cues to action’. In the current vacuum of systemic stability, HCPs have become the primary, and often the sole, trusted navigators for health information, making their endorsement one of the most influential determinants of public vaccine uptake [15, 16].

​Yet, this effective communication is contingent upon the providers' own vaccine confidence. Alarmingly, recent evidence indicates that HCPs in the region, such as pharmacists in Nigeria, exhibit significant risk perceptions and hesitancy toward malaria vaccines [17]. When HCPs lack comprehensive knowledge about the newly introduced R21/Matrix-M vaccine, they may exhibit hesitancy themselves, directly translating into suboptimal recommendation practices and diminished public trust.

Vaccine acceptability is a multidimensional construct closely linked to several dimensions of trust, including trust in vaccines and their safety and effectiveness, trust in health institutions and regulatory systems, and trust in healthcare providers who recommend and administer vaccines. These dimensions have been repeatedly identified as important determinants of vaccine confidence and acceptance [15, 18]. In the global vaccine hesitancy literature, these trust-related factors have predominantly been examined from a demand-side perspective focusing on communities, caregivers, and vaccine recipients [18]. However, in fragile and conflict-affected settings where institutional trust may be weakened, comparatively less attention has been directed toward supply-side determinants, particularly healthcare provider perspectives [19]. This perspective is critical because healthcare providers function as trusted intermediaries between health systems and communities, and their own acceptance of vaccination can influence the strength and credibility of their recommendations. Provider recommendation has consistently been identified as a major determinant of vaccine uptake across diverse populations and settings [20]. Therefore, examining vaccine acceptability among healthcare providers is essential for understanding and strengthening immunization delivery systems in humanitarian and fragile contexts.

​Currently, empirical evidence regarding Sudanese physicians’ knowledge, acceptance, and hesitancy toward the malaria vaccine remains scarce [21]. This lack of data limits the ability of policymakers and public health authorities to design evidence-based communication strategies and targeted interventions. Therefore, this study aimed to: (1) Assess the level of knowledge and acceptability of the R21/Matrix-M malaria vaccine among HCPs in Al-Qadarif and Blue Nile states; (2) Identify the demographic and professional independent predictors of both knowledge and vaccine acceptance using multivariable regression models; and (3) Examine the association between knowledge levels and the willingness to recommend the vaccine within a conflict-affected context. We hypothesized that higher individual knowledge scores would serve as a robust independent predictor of vaccine acceptance, even after controlling for demographic and professional characteristics. These findings are essential to inform national immunization policies, optimize vaccine introduction strategies, and enhance the effectiveness of malaria prevention efforts in Sudan.

Methods

Study design

This descriptive cross-sectional study assessed knowledge, acceptance, and concerns regarding the malaria vaccine among healthcare providers in Sudan. Data collection took place between 21 January and 25 February 2025.

Study area

The study was conducted at two major teaching hospitals in conflict-affected regions of Sudan: Al-Qadarif Teaching Hospital (eastern Sudan) and Al-Damazin Teaching Hospital (southern Sudan). These states were deliberately chosen because they represent two of the highest malaria-burden areas in Sudan and were the first to receive the malaria vaccine in October 2024. Although they are teaching hospitals, they serve as major referral and supervisory hubs for primary and secondary facilities where the vaccine is actually administered. This setting allows the study to capture the perspectives of frontline providers most directly involved in the national vaccination campaign while reflecting the regions bearing the greatest malaria burden amid ongoing conflict [7, 22, 23].

The inclusion and exclusion criteria were as follows

Eligible participants were house officers and medical officers actively working during the study period who provided informed consent. These cadres were chosen because they constitute the frontline workforce in teaching hospitals, rotate through all major clinical departments (pediatrics, internal medicine, surgery, and obstetrics/gynecology), and have frequent direct contact with caregivers of children under five years—the primary target group for the malaria vaccine. Physicians who declined participation or did not provide consent were excluded.

Sampling technique, sample size, and study population:

The required sample size was initially calculated via Cochran’s formula [24].

$$n=(Z^2\times p\times (1-p))/d^2$$

(where n is the sample size, Z is the score for a 95% confidence level (1.96), p = 0.5 to ensure maximum variability, and d is the margin of error 5%. Since the total population (N) is finite.

The total population of house officers and medical officers in the two hospitals was 418 (312 in Al-Qadarif Teaching Hospital and 106 in Al-Damazin Teaching Hospital).

The adjusted sample size was calculated via the following formula:

$$n\_adj=\frac{n}{(1+\left(\frac{n-1}{N}\right))}$$

where.

n = 385 (initial sample size),

N = 418 (total population).

The minimum required adjusted sample size was determined to be 201 participants. However, to minimize potential selection bias inherent in convenience sampling and to maximize the study's statistical power, we invited the entire available population of house officers and medical officers in both hospitals. A total of 342 completed questionnaires were retrieved, resulting in an overall response rate of 81.8% (342/418). This high response rate and the inclusion of a larger-than-required sample helped ensure the reliability of the findings despite the challenging field conditions.

Due to the severe administrative disruptions caused by the ongoing armed conflict, a reliable sampling frame (i.e., an updated, official registry of actively working physicians) was unavailable, as the medical workforce has been highly dynamic due to mass displacement. Consequently, probability sampling methods (such as simple random sampling) could not be feasibly implemented. Instead, a convenience sampling approach was adopted. Data were collected through direct, peer-to-peer recruitment by medical data collectors physically present at the selected hospitals, targeting accessible providers who were actively on duty during the study period. This approach ensured the safety of both participants and data collectors while maintaining feasible access. Paper-based questionnaires and face-to-face interviews were not possible because of security concerns. The two largest teaching hospitals (one in each target state) were deliberately selected as they serve as the major referral centers in their respective states, manage the highest patient volume (including internally displaced populations), and provide clinical supervision and training to primary and secondary healthcare facilities where the malaria vaccine is actually administered. Although this selection may limit the generalizability of the findings, it ensures the study captures perspectives from settings with the greatest potential influence on vaccine rollout and community-level uptake.

Data collection tools and procedures

This research utilized a validated questionnaire from previous studies to assess malaria vaccine acceptance and concerns [21] and to determine vaccine awareness [25].

To ensure the reliability of the adopted questionnaire in the current context, internal consistency was assessed. Both scales demonstrated acceptable reliability,and an excellent internal consistency of 0.93 for the 5-item vaccine acceptability scale. The knowledge scale yielded a Cronbach’s alpha of 0.69. During tool validation, item-total correlation was assessed; however, no items were removed as all components were deemed clinically essential for defining minimum vaccine competency in a new national rollout. This marginal reliability is acknowledged as a limitation inherent in exploratory research within emergency settings.

The questionnaire was developed using Google Forms and administered in English, as all participants were physicians proficient in the language. It included a consent section and five main sections addressing the study objectives:

1. Sociodemographic characteristics (age, sex, marital status, educational level, and monthly income).

2. Family profile and personal experience with malaria (including having children under 18 years and concern about them contracting malaria).

3. Knowledge of the malaria vaccine (awareness, source of information, mechanism, doses, effectiveness, target group, benefits, and side effects).

4. Willingness to accept or recommend the vaccine (5 items using a 3-point ordinal Likert scale: certainly, probably, definitely not).

5. Concerns about the vaccine (6 items using a 3-point ordinal Likert scale, where “yes” = 3, “not sure” = 2, and “no” = 1).

Due to the absence of centralized, up-to-date administrative registries amid the conflict, contact with potential participants was established through a decentralized, field-based approach. The research team first coordinated with the medical directorates of the two hospitals to secure institutional approval and facilitate access to the departments. Data collection was then carried out by a team of four trained medical data collectors physically present at the hospitals. These collectors utilized professional networks and department-level duty rosters to identify and approach eligible physicians on duty. A standardized orientation was provided to the collectors by the research leader, covering study objectives, ethical consent procedures, and questionnaire clarification to ensure consistency. To prevent duplicate responses, participants were invited to complete the survey via unique digital links shared directly during the face-to-face recruitment process.

Data management and statistical analysis

Data were initially extracted, cleaned, and coded using Microsoft Excel before being imported into IBM SPSS Statistics (Version 28.0) for formal statistical analysis.

Descriptive statistics and normality testing

Categorical variables, including sociodemographic and professional characteristics, were summarized using frequencies and percentages. For continuous variables (total knowledge and acceptability scores), data distribution was assessed using the Shapiro–Wilk test. Due to significant deviation from normality (p < 0.05) and the presence of skewed data, continuous variables were summarized as medians with Interquartile Ranges (IQR).

​Bivariate analysis

Non-parametric tests were employed to accommodate the skewed nature of the data. The Mann–Whitney U test and Kruskal–Wallis H test were utilized to evaluate differences in median knowledge and acceptability scores across dichotomous and polychotomous categorical variables, respectively. Additionally, Spearman’s rank-order correlation (rho) was calculated to assess the crude monotonic relationship between continuous knowledge scores and vaccine acceptability.

​Multivariable modeling

To control for potential confounders and identify independent predictors, two distinct multivariable regression approaches were strategically applied:

1. ​Multiple Linear Regression (Predictors of Knowledge): A linear regression model was constructed to determine the independent sociodemographic factors associated with the continuous knowledge score. The assumptions of the model were strictly checked; specifically, the absence of multicollinearity among independent variables was confirmed using Tolerance and Variance Inflation Factor (VIF) statistics. Additionally, residual plots were visually examined to confirm the assumptions of homoscedasticity and normality of residuals.

2. ​Multivariate Logistic Regression (Predictors of Acceptability): To translate the findings into actionable public health outcomes (i.e., identifying specific targets for immunization campaigns), the vaccine acceptability score was dichotomized into "high" versus "moderate/low" acceptability using the median score as a threshold. A multivariable logistic regression model was then fitted. Crucially, to prevent the loss of information and maximize statistical power, the knowledge score was retained and entered into the model as a continuous independent variable. Results are presented as Adjusted Odds Ratios (aOR) with corresponding 95% Confidence Intervals (CI). Variables were included in the multivariable models based on theoretical relevance and their performance in the bivariate analysis.

​Sensitivity Analysis

Sensitivity analyses were conducted to rigorously assess the robustness of the findings and validate the categorization of the outcome variable. This included applying an alternative, higher cut-off threshold for high vaccine acceptability (≥ 80% of the total score) and re-running the multivariable logistic regression model. The consistency of the results across these model specifications supported the stability of the observed associations and confirmed they were not mere artifacts of the chosen median cut-point.

​All statistical tests were two-tailed, and a p-value of < 0.05 was considered statistically significant.

Results:

A total of 342 healthcare providers completed the online questionnaire. Their sociodemographic characteristics are summarized in Table 1. The majority were aged 25–30 years (72.8%), male (55.6%), single (90.4%), employed et al.-Qadarif Teaching Hospital (67.0%) and 89.5% encountering malaria cases on a daily basis.

Table 1.

Baseline sociodemographic and professional characteristics of healthcare providers (N = 342)

Characteristics	n (%)
Age (Years)
• Median (IQR)*	27 (26–28)
• 20–25	71 (20.8%)
• 26–30	249 (72.8%)
• > 30	22 (6.4%)
Gender
• Male	190 (55.6%)
• Female	152 (44.4%)
Marital Status
• Single	309 (90.4%)
• Married/Other	33 (9.6%)
Monthly Income (SDG)
• < 500,000	304 (88.9%)
• > 500,000	38 (11.1%)
Hospital of Work
• Al-Qadarif Teaching Hospital	229 (67.0%)
• Al-Damazin Teaching Hospital	113 (33.0%)
Professional Role
• House Officer (Intern)	206 (60.2%)
• Medical Officer	136 (39.8%)
Frequency of encountering malaria cases
• Daily	306 (89.5%)
• Weekly	28 (8.2%)
• Monthly	4 (1.2%)
• Rarely	4 (1.2%)

IQR: Interquartile Range. SDG: Sudanese Pound. Age is presented as Median (IQR) due to non-normal distribution (Shapiro–Wilk test, p < 0.05)

Family profile and personal experience with malaria are presented in Supplementary Table S1. Only 12.9% had biological children, and 25.1% of those with children under 18 years reported a recent malaria diagnosis in at least one child. High concern about children contracting malaria was reported by 31.9% of participants.

Detailed responses to individual knowledge items are shown in Supplementary Table S2.

Overall, 90.6% of participants failed to correctly identify the required four-dose vaccination schedule, including 73.1% who reported that they did not know the schedule and 17.5% who selected an incorrect response. Similarly, 60.8% failed to identify the target age group for vaccination (54.7% reported not knowing and 6.1% selected an incorrect age group). The most common sources of information were social media (48.5%) and other healthcare providers (45.0%), as illustrated in Fig. 1.

Fig. 1.

source of information regarding malaria vaccine

Vaccine acceptance was moderate to high (Table 2). Nearly half of the participants (49.4%) stated they would “certainly” allow their own child to receive the malaria vaccine, and more than 50% reported they would “certainly” recommend it to family members, friends, colleagues, and patients.

Table 2.

Acceptability of the malaria vaccine among healthcare providers (N = 342)

Acceptability Indicators	n (%)
Are you willing to vaccinate your child when the vaccine is available?
• Yes	258 (75.4%)
• No	84 (24.6%)
Likelihood of recommending the vaccine to…
Family members
• Yes	291 (85.1%)
• No	51 (14.9%)
Friends' children
• Yes	288 (84.2%)
• No	54 (15.8%)
Fellow healthcare professionals' children
• Yes	285 (83.3%)
• No	57 (16.7%)
Patients seeking professional advice
• Yes	303 (88.6%)
• No	39 (11.4%)
Overall Acceptance Score (Out of 25)
• Median (IQR)*	22 (20–25)

IQR: Interquartile Range. The overall acceptance score was calculated based on a 5-point Likert scale for all acceptability items (higher scores indicate higher acceptability)

Overall, 64.0% of participants expressed high concern about the vaccine, mainly due to potential adverse effects (57.0%), uncertain effectiveness (42.7%), and challenges related to cold-chain handling in Sudan (56.4%).

Bivariate analysis

Mann–Whitney U and Kruskal–Wallis H tests evaluated the differences in knowledge and acceptability scores across baseline characteristics. Statistically significant differences in knowledge scores were observed based on the hospital of work (p < 0.001), age group (p < 0.001), and gender (p = 0.035). However, no significant difference in knowledge was found regarding the professional role (p = 0.343) (Table 3).

Table 3.

Bivariate analysis of sociodemographic factors associated with Knowledge and Vaccine Acceptability (N = 342)

Variables	Knowledge Score	Vaccine Acceptability
	p-value*	p-value*
Gender (Male vs. Female)	0.035*	0.115
Hospital (Al-Qadarif Teaching Hospital vs. Al-Damazin Teaching Hospital)	< 0.001*	0.185
Age Group (20–25, 26–30, > 30)	< 0.001*	0.240
Professional Role (House vs. Medical Officer)	0.343	0.210

p-values were calculated using Mann–Whitney U and Kruskal–Wallis H tests. *Significant values (p < 0.05)

Correlation Analysis

A Spearman’s rank-order correlation demonstrated a statistically significant, weak positive association between the total knowledge score and vaccine acceptability (rho = 0.127, p = 0.017).

Multivariate Analysis

Predictors of knowledge score (linear regression)

A multiple linear regression analysis was conducted to evaluate factors associated with the providers' knowledge scores. The model indicated that age category (Standardized Beta = 0.156, p = 0.004) and hospital of work (Standardized Beta = 0.212, p < 0.001) were statistically significant predictors of knowledge levels. Gender (p = 0.098) and professional role (p = 0.320) demonstrated no significant association. Collinearity diagnostics confirmed the absence of multicollinearity among the variables (all VIF values < 5) (Table 4).

Table 4.

Multivariable Linear Regression Analysis of Factors Associated with Total Knowledge Scores Regarding the R21 Malaria Vaccine.(N = 342)

	Unstandardized Coefficients		Standardized Coefficients	t	Sig	95.0% Confidence Interval for B		Collinearity Statistics
	B	Std. Error	Beta			Lower Bound	Upper Bound	Tolerance	VIF
(Constant)	0.500	0.956		0.523	0.601	−1.380	2.380
Age	0.088	0.031	0.156	2.871	0.004*	0.028	0.149	0.928	1.078
Gender	−0.173	0.187	−0.050	−0.925	0.356	−0.541	0.195	0.950	1.053
Hospital	0.782	0.195	0.212	4.002	< 0.001*	0.398	1.167	0.971	1.030
Role	0.047	0.190	0.013	0.245	0.807	−0.328	0.421	0.948	1.055

CI = Confidence Interval, aOR = Adjusted Odds Ratio. *Significant values (p < 0.05)

Predictors of vaccine acceptability (logistic regression)

A multivariate logistic regression model was utilized to identify independent factors associated with high vaccine acceptability. After adjusting for potential confounders, the continuous knowledge score emerged as the sole statistically significant predictor of acceptability (aOR = 1.15, 95% CI: 1.01–1.32, p = 0.033). Each one-unit increase in the continuous knowledge score increased the odds of high vaccine acceptance by 15%. Other demographic and professional variables, including age (p = 0.996), gender (p = 0.201), hospital of work (p = 0.832), and professional role (p = 0.334), showed no statistically significant association in the adjusted model (Table 5).

Table 5.

Multivariable Logistic Regression Analysis of Independent Predictors for High Vaccine Acceptability Among Healthcare Providers

	B	S.E	Wald	df	Sig	Exp(B)	95% C.I.for EXP(B)
							Lower	Upper
Age	0.024	0.039	0.396	1	0.529	1.025	0.950	1.106
Gender	0.341	0.230	2.197	1	0.138	1.407	0.896	2.209
Hospital	0.003	0.245	0.000	1	0.989	1.003	0.621	1.622
Role	0.292	0.233	1.562	1	0.211	1.339	0.847	2.115
Know_Score	0.143	0.067	4.540	1	0.033*	1.154	1.012	1.316
Constant	−1.834	1.190	2.376	1	0.123	0.160

CI = Confidence Interval, aOR = Adjusted Odds Ratio. *Significant values (p < 0.05)

Sensitivity analyses confirmed the robustness of these findings; when applying an alternative higher cut-off threshold for high acceptability (≥ 80% of the total score), the continuous knowledge score remained a statistically significant predictor (aOR = 1.14, 95% CI: 1.01–1.29, p = 0.041). This confirms the association is not a mere artifact of the chosen median cut-point.

Concerns about the malaria vaccine

Concerns regarding the malaria vaccine were common, with 64.0% of participants reporting high overall concern. The most frequently reported concerns were potential adverse effects following immunization (57.0%), worry about the vaccine’s effectiveness (42.7% feared failure to protect against malaria), and poor vaccine handling and storage conditions in Sudan (56.4%). Additionally, 29.8% expressed concern that the vaccine itself could cause malaria infection. Despite these concerns, 51.5% of participants believed that malaria vaccination is necessary, and 73.1% reported a general belief in vaccination. Detailed responses to individual concern items are presented in Supplementary Table S3.

Discussion

This study found that the vast majority of respondents (82.5%) had heard of the malaria vaccine, indicating greater awareness compared to prior findings reported by Hamza et al. [21]. However, this high general awareness did not equate to comprehensive clinical understanding. A significant proportion of the participants were unaware of critical operational details, such as the correct four-dose schedule (90.6%) and the specific target age group (60.8%). In contrast, Mugasia et al. [26] reported that 98.6% of nurses in comparable settings demonstrated high knowledge levels regarding vaccine protocols. To identify factors associated with these knowledge gaps, our multivariable linear regression model revealed that older age and the specific hospital of work were the only significant independent predictors of higher knowledge scores. This aligns with findings by Albaker et al. [27] and Saleh et al. [28], suggesting that clinical experience and institutional exposure play critical roles in health literacy among professionals.

This suggests a sequential pathway where accumulated clinical experience (older age) enhances technical knowledge, which, as our subsequent models demonstrate, serves as the primary catalyst for vaccine acceptance.

​Information sources in a conflict setting

Social media platforms and peer networks were the most commonly reported sources of vaccine-related information (48.5% and 45.0%, respectively). This high reliance on digital platforms is likely a direct consequence of the ongoing armed conflict in Sudan. Since April 2023, the war has severely disrupted formal health communication and continuous medical education systems, with an estimated 70–80% of healthcare facilities rendered non-functional in conflict hotspots [7]. In this vacuum of institutional guidance, healthcare providers have increasingly turned to informal digital channels as rapid, accessible alternatives. However, this heavy reliance on unregulated social media introduces a dual-edged challenge; while it facilitates rapid peer support, it simultaneously exposes providers to the pervasive risk of medical misinformation and unverified data (an infodemic). In a conflict setting where official health advisories are disrupted, encountering conflicting narratives regarding vaccine safety on these platforms could inadvertently fuel the very hesitancy we seek to mitigate. Despite this, HCPs remain a pivotal and trusted source of vaccine information for the public [29], emphasizing the urgent need to secure these digital channels with verified medical guidelines.

​Predictors of acceptability and theoretical framing

Regarding vaccine acceptance, our findings indicate a generally favorable attitude, with nearly half of the participants (49.4%) expressing certainty in vaccinating their own children and recommending it to patients. Crucially, the multivariate logistic regression analysis revealed that the continuous knowledge score was the only statistically significant independent predictor of high vaccine acceptability in our model (aOR = 1.15, 95% CI: 1.01–1.32, p = 0.033). Although the initial non-parametric correlation was statistically significant but weak (rho = 0.127), the robust adjusted regression model confirms its clinical relevance. This finding closely aligns with the Health Belief Model (HBM), which posits that health-related decisions are driven by the mitigation of perceived barriers [14]. By utilizing a continuous knowledge score, our model demonstrates that every incremental gain in understanding the R21 vaccine specifications directly reduces clinical uncertainty, thereby increasing providers' confidence to accept and recommend it.

While technical knowledge was evaluated as a composite score in the multivariable model, an item-level descriptive examination provides additional insight into specific domains where knowledge gaps were concentrated. The most substantial deficits were observed in operational and implementation-related knowledge. Notably, 73.1% of participants reported that they did not know the correct vaccination schedule, and only 9.4% correctly identified the recommended four-dose regimen for the R21 malaria vaccine [30]. Similarly, 61.7% reported uncertainty regarding vaccine efficacy. In contrast, awareness of general vaccine safety concepts was comparatively higher, with 78.9% recognizing that the vaccine may be associated with side effects and 74.0% acknowledging potential risks related to incorrect administration. Although the present analysis was not designed to assess the independent contribution of individual knowledge domains to vaccine acceptability, these findings suggest that knowledge gaps were particularly concentrated in operational and efficacy-related aspects of the vaccine. Given that these domains exhibited the highest levels of uncertainty, future educational interventions may benefit from prioritizing practical implementation knowledge, including vaccination schedules, efficacy expectations, and deployment procedures.

Furthermore, the robustness of this association between precise clinical knowledge and vaccine acceptance was strongly supported by our sensitivity analyses. By demonstrating consistent findings across different acceptability cut-off thresholds, the analysis reinforces the reliability of providers' knowledge as a key determinant, completely independent of methodological assumptions or arbitrary scoring boundaries.

While local providers may have limited direct influence on globalized digital misinformation networks, substantial evidence indicates that healthcare provider recommendations remain among the strongest determinants of vaccine acceptance and uptake, even among initially hesitant individuals. In conflict-affected settings such as Sudan, where formal communication channels are disrupted, interpersonal trust in local healthcare providers may serve as a resilient buffer against misinformation. Frontline providers who are well-informed and supportive of vaccination can counter rumors at the point of care and facilitate informed vaccine decision-making within their communities [20].

​The homogenizing effect of conflict

Interestingly, demographic factors and geographic location (Al-Qadarif vs. Blue Nile) did not independently influence vaccine acceptance in the adjusted model. This homogenous high acceptability across diverse demographic groups and conflict-affected states highlights a critical phenomenon: the profound impact of systemic health crises on risk perception. The severe degradation of environmental health services during the conflict has heightened the perceived susceptibility to vector-borne diseases [31]. In such volatile environments, the imminent threat of malaria outbreaks overrides conventional geographic differences, forging a unified professional consensus on the necessity of preventive interventions. While the conflict has heightened the perceived susceptibility to malaria, it may simultaneously erode 'Institutional Trust'—a known pillar of vaccine confidence. In the absence of stable health authorities, the high reliance on informal networks (48.5%) suggests that HCPs are substituting formal institutional guidance with peer-validated information. This shift necessitates that vaccine communication strategies focus on rebuilding professional trust through transparent, evidence-based digital outreach.

Policy implications

These empirical findings yield specific policy implications for the Sudanese health authorities. Because general acceptability is high but contingent upon precise technical knowledge, immunization campaigns must pivot from generalized promotional messaging to targeted educational interventions. Training modules tailored for Sudanese providers should prioritize logistical specifics—such as the dosage schedule and cold-chain handling—rather than merely emphasizing the vaccine's general importance. Given the disruption of formal communication channels, deploying these modules through secure, decentralized digital professional networks is recommended.

To address systemic concerns regarding cold-chain integrity (56.4%), health authorities should prioritize solar-powered storage. Furthermore, clinical uncertainty (57.0%) must be mitigated through technical webinars and peer-validated digital outreach.

This apparent perception-reality gap should be interpreted within Sudan’s challenging environmental and infrastructural context. High ambient temperatures increase the vulnerability of vaccine supply chains to heat exposure when cold-chain systems are disrupted. This vulnerability has been further exacerbated by the ongoing conflict, which has severely damaged health infrastructure, disrupted electricity supplies, and constrained the transportation of medical commodities. In such settings, frontline healthcare providers’ concerns regarding cold-chain integrity (56.4%) likely reflect rational responses to operational challenges rather than simple knowledge deficits. Consequently, educational interventions should extend beyond communicating the R21 vaccine’s recommended storage temperature of 2–8°C and should be accompanied by practical system-level solutions, including strengthening cold-chain infrastructure and expanding the use of solar-powered refrigeration technologies [30].

Ultimately, these findings contribute to the growing body of global evidence on vaccine acceptance in low-resource and conflict-affected settings, highlighting the critical role of frontline provider knowledge in shaping resilient public health outcomes amidst systemic fragility.

Strengths and limitations

To our knowledge, this is one of the earliest attempts to evaluate HCPs' acceptance of the R21 malaria vaccine in Sudan during an active armed conflict, providing crucial real-time evidence. Methodologically, continuous knowledge scoring and sensitivity analyses bolster the robustness of the modeling. However, the study has notable limitations. The reliance on convenience sampling—necessitated by severe security constraints and the mass displacement of medical personnel—may introduce selection bias, limiting the generalizability of findings beyond the selected teaching hospitals to the broader national workforce. Furthermore, while the acceptability scale demonstrated excellent internal consistency (α = 0.93), the knowledge scale yielded a borderline acceptable reliability (α = 0.69). This is generally deemed acceptable for exploratory field research in acute emergency settings, yet future studies should consider refining the instrument items to optimize internal consistency. Lastly, the cross-sectional design precludes causal inferences. Furthermore, the study could not access HCPs in active combat zones or besieged areas, who may face a severe 'information blackout' and logistical isolation, potentially leading to different levels of knowledge and acceptability compared to our study population.

Furthermore, the geographical context of our convenience sampling requires careful consideration when interpreting generalizability across Sudan. Al-Qadarif and Blue Nile states, although heavily affected by population displacement, retained relative administrative and security stability during the study period. This differs substantially from highly conflict-affected regions such as Khartoum and Darfur, where WHO estimates indicate that approximately 70–80% of health facilities are non-functional or only partially functional because of conflict-related destruction, insecurity, and resource shortages. Consequently, our findings are most applicable to relatively stable or transitional conflict settings and may not fully reflect vaccine acceptability dynamics in areas experiencing severe health-system disruption. Future studies in highly volatile regions are needed to assess acceptability under conditions of near-complete infrastructure collapse. (6,7,8).

Conclusion

​This study highlights a critical dichotomy among healthcare providers in conflict-affected Sudan: while general acceptability of the newly introduced R21/Matrix-M malaria vaccine is encouragingly high, it is juxtaposed with significant gaps in specific technical knowledge. Crucially, multivariable analysis established that the providers' knowledge level is the only statistically significant independent predictor in this model of vaccine acceptance. This indicates that vaccine hesitancy in this context is not driven by demographic or geographic variations, but rather by clinical uncertainty and valid systemic concerns, particularly regarding safety and cold-chain handling within a fragile health infrastructure. To ensure the successful national rollout of the vaccine, health authorities must pivot from generalized promotional campaigns to targeted educational modules that address specific clinical protocols and safety profiles. Given the severe disruption of formal institutional channels due to the ongoing conflict, leveraging secure digital professional networks is essential to rapidly build provider confidence, which remains a fundamental prerequisite for broader community uptake. Future research should encompass broader geographic regions and diverse healthcare cadres to monitor longitudinal trends in vaccine confidence as the immunization program expands.

Abbreviations

WHO

World Health Organization.

ITNs

Insecticide-Treated Nets.

IRS

Indoor Residual Spraying.

MVIP

Malaria Vaccine Implementation Programme.

UNICEF

United Nations Children’s Fund.

EMR

Eastern Mediterranean region.

SDG

Sudanese Pound

Author contributions

RMB: conceptualization, project administration, methodology, writing original draft, revised and edited manuscript. ABME: conceptualization, formal analysis and visualization. WMMA: Writing original draft revised and edited manuscript. LSYO: Conceptualization, methodology and revised manuscript. AM: conceptualization, supervision and edited manuscript. DAAA: conceptualization, writing original draft and revised manuscript. MAAR: Conceptualization and writing original draft. AAHM: Conceptualization and revised manuscript. BAOH: Data collection and revised manuscript. AAO: Data collection and revised manuscript. EFEE: Data collection and revised manuscript. MMAA: Data collection and revised manuscript. YMAA: statistical analysis, supervision, writing, review & editing.

Funding

The authors received no financial support for the research, authorship, or publication of this article.

Availability of data and materials

The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

​Ethical approval for this study was obtained from the Local Ethics Committee of the Ministry of Health in the Blue Nile State, Sudan (Approval ID: RREC-BNR-03). The study was conducted in accordance with the principles outlined in the Declaration of Helsinki. Informed consent was obtained from all participants prior to their inclusion in the study; the consent form was attached to the digital questionnaire, outlining the study’s purpose, objectives, the voluntary nature of participation, and the right to withdraw at any time. To ensure confidentiality, all data were anonymized, and no personal identifying information was collected.

​Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.