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COVID-19 vaccination intention among internally displaced persons in complex humanitarian emergency context, Northeast Nigeria

  • Saheed Gidado ,

    Roles Conceptualization, Formal analysis, Supervision, Writing – original draft, Writing – review & editing

    saheed.gidado@tuni.fi

    Affiliations Health Sciences Unit, Faculty of Social Sciences, Tampere University, Tampere, Finland, African Field Epidemiology Network, Nigeria Country Office, Abuja, Nigeria

  • Melton Musa,

    Roles Investigation, Methodology, Project administration, Supervision, Validation, Writing – review & editing

    Affiliation African Field Epidemiology Network, Borno State Field Office, Maiduguri, Nigeria

  • Ahmed Ibrahim Ba’aba,

    Roles Investigation, Methodology, Supervision, Validation, Writing – review & editing

    Affiliation African Field Epidemiology Network, Yobe State Field Office, Damaturu, Nigeria

  • Lilian Akudo Okeke,

    Roles Investigation, Methodology, Supervision, Validation, Writing – review & editing

    Affiliation African Field Epidemiology Network, Adamawa State Field Office, Yola, Nigeria

  • Patrick M. Nguku,

    Roles Methodology, Project administration, Resources, Supervision, Validation, Writing – review & editing

    Affiliation African Field Epidemiology Network, Nigeria Country Office, Abuja, Nigeria

  • Isa Ali Hassan,

    Roles Investigation, Methodology, Supervision, Validation, Writing – review & editing

    Affiliation Borno State Ministry of Health, Maiduguri, Borno State, Nigeria

  • Ibrahim Muhammad Bande,

    Roles Investigation, Methodology, Supervision, Validation, Writing – review & editing

    Affiliation Department of Disease Control and Immunization, Yobe State Primary Health Care Board, Damaturu, Yobe State, Nigeria

  • Rabi Usman,

    Roles Investigation, Methodology, Supervision, Validation, Writing – review & editing

    Affiliation Resolve to Save Lives, Abuja, Nigeria

  • Gideon Ugbenyo,

    Roles Data curation, Formal analysis, Software, Writing – review & editing

    Affiliation African Field Epidemiology Network, Nigeria Country Office, Abuja, Nigeria

  • Idris Suleman Hadejia,

    Roles Investigation, Resources, Supervision, Validation, Writing – review & editing

    Affiliation Department of Community Medicine, Ahmadu Bello University, Zaria, Kaduna State, Nigeria

  • J. Pekka Nuorti,

    Roles Conceptualization, Funding acquisition, Investigation, Writing – original draft, Writing – review & editing

    Affiliation Health Sciences Unit, Faculty of Social Sciences, Tampere University, Tampere, Finland

  • Salla Atkins

    Roles Conceptualization, Project administration, Resources, Writing – original draft, Writing – review & editing

    Affiliation Health Sciences Unit, Faculty of Social Sciences, Tampere University, Tampere, Finland

Abstract

Internally displaced persons (IDPs) are at high risk for COVID-19 transmission because of congested and unsanitary living conditions. COVID-19 vaccination is essential to build population immunity and prevent severe disease among this population. We determined the prevalence and factors associated with intention to accept COVID-19 vaccine among IDPs in Northeast Nigeria. This cross-sectional study, conducted during July–December 2022, included 1,537 unvaccinated IDPs from 18 IDPs camps. We performed a complex sample survey analysis and described participants’ characteristics and vaccination intention with weighted descriptive statistics. We fitted weighted logistic regression models and computed adjusted odds ratios with 95% confidence intervals to identify factors associated with intention to accept COVID-19 vaccine. Of 1,537 IDPs, 55.4% were 18–39 years old, 82.6% were females, and 88.6% had no formal education. Among them, 63.5% (95% CI: 59.0–68.1) expressed intention to accept COVID-19 vaccine. Among the IDPs who intended to reject vaccine, 42.8% provided no reason, 35.3% had COVID-19 misconceptions, 9.5% reported vaccine safety concerns, and 7.4% felt no need. IDPs who perceived COVID-19 as severe (Adjusted Odds Ratio (AOR) = 2.31, [95% CI: 1.35–3.96]), perceived COVID-19 vaccine as effective (AOR = 4.28, [95% CI: 2.46–7.44]) and resided in official camps (AOR = 3.29, [95% CI: 1.94–5.56]) were more likely to accept COVID-19 vaccine. However, IDPs who resided 2 kilometers or farther from the nearest health facility (AOR = 0.34, [95% CI: 0.20–0.58]) were less likely to accept vaccine. Intention to accept COVID-19 vaccine among the IDPs was suboptimal. To improve vaccination acceptance among this population, health education and risk communication should be intensified to counter misinformation, strengthen vaccine confidence, and shape perception of COVID-19 severity, focusing on IDPs in unofficial camps. Appropriate interventions to deliver vaccines to remote households should be ramped up.

Introduction

Coronavirus disease (COVID-19), an infectious disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified in December 2019 in Wuhan, China [1]. Following the rapid spread of the disease from its origin to many other countries worldwide, the World Health Organization (WHO), on 30 January 2020, declared the COVID-19 outbreak a public health emergency of international concern and characterized the outbreak as a pandemic on 11 March 2020 [2]. Since the pandemic started, over 774 million COVID-19 cases and more than 7 million deaths have been recorded globally [3]. In Africa, COVID-19 infections numbered over 9.5 million individuals, with over 175,000 deaths as of 25 February 2024 [3]. Apart from causing huge morbidities and mortalities, the pandemic has disrupted preventive, promotive, and curative healthcare services, particularly in Sub-Saharan Africa (SSA), causing indirect morbidities and mortalities [4, 5]. On 5 May 2023, WHO declared the end of COVID-19 global health emergency [6]. Nigeria recorded her first confirmed COVID-19 case on 27 February 2020. As of 3 March 2024, the country has recorded over 267,000 confirmed cases and more than 3,000 deaths nationwide [7]. About 46% of Nigeria’s total population have been vaccinated with at least one dose of a COVID-19 vaccine, while 39% have been vaccinated with a complete primary series of a COVID-19 vaccine as of 26 November 2023 [8].

Generally, internally displaced persons (IDPs) are considered among high-risk populations for COVID-19 infection [9]. According to the United Nations Guiding Principles on Internal Displacement, IDPs are ‘persons or groups of persons who have been forced or obliged to flee or to leave their homes or places of habitual residence, in particular as a result of or in order to avoid the effects of armed conflict, situations of generalized violence, violations of human rights or natural or human-made disasters, and who have not crossed an internationally recognized State border’ [10]. In Northeast Nigeria, over two million persons are currently displaced due to a protracted complex humanitarian emergency in the region precipitated by the rebellious activities of armed insurgent groups [11]. Apart from the congested and unsanitary living conditions which predispose the IDPs to an elevated risk of COVID-19 transmission, the limited access of this population to health interventions, including COVID-19 testing and case management facilities, also increases their risk of mortality from COVID-19 infection [12, 13]. Sadly, IDPs face considerable challenges and difficulties in adhering to COVID-19 preventive measures owing to poor environmental and other contextual factors, further exacerbating the risk of disease transmission among this population [14, 15]. Although COVID-19 is no longer considered a public health emergency, there is a risk of the emergence of new variants that could be more transmissible and/or more severe with new surges in cases and deaths [16]. Against this backdrop, it is essential to optimize COVID-19 vaccination uptake among the IDPs to build population immunity against circulating virus variants and prevent severe COVID-19 infection, particularly given their elevated risk for COVID-19 infection, limited access to health facilities and interventions and the contextual obstacles to adopting COVID-19 preventive practices.

According to the WHO, COVID-19 vaccines are vital tools in the COVID-19 pandemic response [17]. However, the acceptance of COVID-19 vaccination among different populations in various contexts has been negatively impacted by widespread controversy, misconceptions, and mistrust regarding vaccine safety and effectiveness [18, 19]. For instance, the global pooled COVID-19 vaccine acceptance was approximately 65% [20]. In Nigeria, previous research reported an estimated pooled COVID-19 vaccine acceptance of 20.0%– 58.2% among the adult population [21]. Furthermore, a study conducted among IDPs in Northeast Nigeria revealed that less than half (46.3%) of this population had received at least one dose of COVID-19 vaccine (Oxford/AstraZeneca or Moderna), while just about one-third (33.1%) had received two doses as of November 2022 [22].

In the wake of the extensive misinformation and mistrust that trailed the safety and effectiveness of COVID-19 vaccine, several studies were commissioned to investigate COVID-19 vaccination intention among different populations to enrich the literature and inform strategies to improve vaccine acceptance. However, the majority of these studies were conducted in stable, non-humanitarian contexts and focused on the general population, healthcare workers, students, and chronically ill patients, among others [2330]. Evidently, there is a dearth of research on COVID-19 vaccination intention among IDPs in humanitarian emergency contexts. As reported in the published literature, findings of research conducted among different population sub-groups in stable, non-humanitarian contexts cannot simply be extrapolated to inform disease prevention and control interventions in humanitarian emergency situations [31]. Accordingly, we conducted this study to determine the prevalence and factors associated with intention to accept COVID-19 vaccine among IDPs in Northeast Nigeria.

Materials and methods

Study setting

This study was conducted in the context of a complex humanitarian emergency in Borno, Adamawa, and Yobe States, otherwise known as the BAY States. These three states are among Nigeria’s 36 States (and the Federal Capital Territory). Situated in Northeast Nigeria, the BAY States share international borders with Niger, Chad, and Cameroun. Borno and Adamawa States have a population of 6,111,462 and 4,902,055, respectively, while Yobe State has a population of 3,649,607 [32]. Altogether, these three states host an estimated 284 IDPs camps and camp-like structures with about 195,901 households and 855,020 IDPs [33]. Several IDPs camps are designated as official (formal) camps because of the presence of Government authorities and camp management structure. Besides the official camps, there are a number of unofficial (informal) camps and camp-like settings in these States. Health care services are provided by health facilities located in the IDPs camps, particularly the official camps. However, several other facilities outside the camps, but mostly within the host communities, also serve the IDPs.

Study design and data source

This cross-sectional study included a total of 1,537 IDPs aged 18 years and above, spread across 18 formal and informal IDPs camps in Borno, Adamawa, and Yobe States (BAY States) in Nigeria’s northeast region. These IDPs were among the participants enrolled from July 25 to December 5, 2022, in a complex sample household survey to investigate COVID-19 knowledge, risk perception, and adherence to COVID-19 preventive measures among IDPs in the BAY States, Northeast Nigeria [22]. Due to practical and logistic considerations, participants enrolled in the complex sample household survey were sampled using a complex sampling methodology. As of their enrollment in the complex sample household survey, the IDPs included in the current study had not received any dose of COVID-19 vaccine based on history (self-report). The socio-demographic and household data of these 1,537 IDPs, as well as data regarding their COVID-19 knowledge, risk perception, and vaccination intention, were extracted from the database of the complex sample household survey. The sampling methodology and data collection approach for the complex sample household survey have been described elsewhere [22]. In brief, 18 IDP camps were selected across the BAY States, six in each state, based on key criteria derived from the International Organization for Migration (IOM) ’s field assessment data, Northeast Nigeria Displacement Report Round 40 –March 2022 [33]. Each camp was further stratified into four distinct, well-delineated geographical strata. A simple random sampling technique was employed to proportionately sample households from each stratum based on the population size of the stratum. In each selected household, one household member aged 18 years or older was randomly selected and interviewed within the household to maintain privacy and confidentiality [22]. Data for the complex sample household survey were collected using a semi-structured data collection instrument uploaded on Open Data Kit (ODK). This data instrument is included as S1 File.

Study variables

In the current study, the outcome variable was COVID-19 vaccination intention (intention to accept or reject COVID-19 vaccination). This variable was measured by asking the participants whether they would accept or reject COVID-19 vaccine. The binary response for the outcome variable was ‘reject’ (coded as 0) or ‘accept’ (coded as 1). For the purpose of data analysis, we designated ‘reject’ as the outcome reference category. The explanatory variables were grouped under different sections and included 1) socio-demographic data such as age, gender, highest education attained, marital status, religion, and occupation, 2) households and camps’ characteristics data including estimated monthly household income, duration of residence in IDPs camps, household distance to the nearest health facility, camp status (official versus unofficial), and state of IDPs camp location, 3) participants’ COVID-19-related knowledge, and 4) perception-related variables which included participants’ perceived COVID-19 susceptibility, severity, and vaccine effectiveness. Table 1 presents an overview of the study variables and their categories.

Assessment of COVID-19 knowledge

We assessed COVID-19-related knowledge using a 12-point assessment tool that included knowledge questions across three key domains, namely: 1) signs and symptoms of COVID-19, 2) mode of spread, and 3) COVID-19 preventive measures. This method is similar to the approach employed by other authors [34, 35]. One point was recorded for every correct response. Participants who scored 6 points and above (out of 12 points) were considered to have adequate knowledge, while those who scored less than 6 points possessed poor knowledge [36]. The assessment tool to evaluate COVID-19-related knowledge is included as S2 File.

Assessment of perception variables

We assessed three variables related to participants’ perception of COVID-19 and COVID-19 vaccine using an adapted Risk Behavior Diagnosis (RBD) scale [37]. These variables were 1) perceived susceptibility to COVID-19, 2) perceived severity of COVID-19, and 3) perceived effectiveness of COVID-19 vaccine. We used a 3-item scale to assess each of the three perception variables and evaluated each item on a 5-point Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). We utilized Cronbach’s alpha coefficient of reliability to determine the internal consistency of the scales for the different perception scales. The Cronbach’s alpha values for perceived susceptibility, perceived severity, and perceived vaccine effectiveness were 0.95, 0.93, and 0.96, respectively, indicating a very high internal consistency of these scales [38]. Further, we summed up the Likert scale scores for all three items in each perception scale to obtain a composite score ranging from 3 to 15 for each scale. We then performed a median split on the composite Likert scale scores of each perception scale to categorize participants into low and high perception categories for the respective perception scales [39, 40]. The list of items for the different perception scales is included as S3 File.

Data analysis and statistical methods

To account for the differential probabilities of selecting study participants using a complex sampling approach rather than a simple random sampling method, we performed a complex sample survey data analysis, consistent with the recommended data analysis approach for complex sampling surveys [41]. We employed an inverse probability weighting approach to determine the survey weight for each study participant. With this survey weight variable, we specified a survey design, created a survey design object, and performed a complex survey analysis to obtain weighted statistical estimates, proportions, standard errors, and confidence intervals [42]. We conducted a weighted univariate analysis to describe participants’ socio-demographics, COVID-19 vaccination intention, and other characteristics. We used the Rao-Scott chi-square test, a design-adjusted version of the Pearson chi-square test, to determine the relationship between vaccination intention and key participants’ characteristics in accordance with the standard statistical procedure for complex sample survey analysis [42]. Furthermore, we performed a weighted crude logistic regression analysis to determine the unadjusted association between each explanatory variable and vaccination intention, designating ‘would reject vaccine’ as the outcome reference category. Employing a backward stepwise regression approach, we fitted weighted multivariable logistic regression models to estimate the covariate-adjusted association between the explanatory variables and vaccination intention. Weighted adjusted odds ratios with 95% confidence intervals were computed. Additionally, we utilized the variance inflation factor (VIF) to examine multicollinearity among the explanatory variables in the multivariable models. The VIF values for all the variables were less than 5, indicating low multicollinearity among these variables [43]. Finally, the Akaike Information Criterion (AIC) was used to compare the quality of the different multivariable model candidates [44]. The model with the smallest AIC value was selected as the best-fit model for our data. Data were analyzed with R statistical and computing software version R-4.2.2. [45].

Ethical approval and consent to participate

Approval for this study was granted by the National Health Research Ethics Committee of Nigeria (NHREC) [NHREC Approval Number: NHREC/01/01/2007-14/06/2022; NHREC Assigned Number: NHREC/01/01/2007]. In addition, we obtained the consent, approval, and permission of the Borno State Ministry of Health (SHREC Approval No: 45/2022), Adamawa State Ministry of Health (Approval No: ADHREC 05/07/2022/051), and Yobe State Ministry of Health and Human Services (Approval No: YB/MOH/HREC/04/22/010). Prior to the conduct of the original complex sample household survey, we explained the purpose, procedure, and benefit of the research in the local language to study participants and responded to their questions and concerns. Furthermore, we assured the participants of voluntary participation and the opportunity to withdraw from the study at any time without prejudice in line with the Helsinki Declaration [46]. Moreover, we assured and maintained confidentiality during and after the study. Owing to heightened insecurity in the research area, participants’ fear of being persecuted, and low education level, we obtained verbal informed consent from the participants in the presence of legally authorized representatives. We documented their affirmation and consent to participate in the study in the researchers’ notes and the data collection tool. Mindful of the vulnerability of our study participants, we were guided by key considerations of health research ethics in humanitarian contexts as described in the published literature [47].

Inclusivity in global research

Additional information regarding the ethical, cultural, and scientific considerations specific to inclusivity in global research is included in the S1 Checklist.

Results

Socio-demographic characteristics

A total of 1,537 participants were enrolled. There was no missing data element in the extracted data file of these participants. The weighted median age of the participants was 36 years (95% CI: 35–40 years) with an interquartile range of 15 years. Table 2 shows the socio-demographic characteristics of the participants. Of the IDPs, 23.6% (95% CI: 19.7–28.0) were 18 to 29 years old, while 31.8% (95% CI: 27.4–36.0) were aged 30–39 years. Most of the IDPs were females: 82.6% (95% CI: 79.1–86.0), had no formal education: 88.6% (95% CI: 85.7–91.0), unemployed: 52.2% (95% CI: 47.4–57.0) and resided in households that earn less than 30 US dollars per month: 85.5% (95% CI: 82.3–89.0).

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Table 2. Socio-demographic characteristics of study participants.

https://doi.org/10.1371/journal.pone.0308139.t002

Knowledge and perception regarding COVID-19

Among the IDPs, 25.7% (95% CI: 21.6–29.8) were considered to have adequate COVID-19 knowledge, 48.7% (95% CI: 44.0–53.4) perceived themselves to be susceptible to COVID-19, 43.2% (95% CI: 38.5–47.9) perceived COVID-19 as severe, while 56.7% (95% CI: 52.0–61.4) perceived COVID-19 vaccine as effective.

COVID-19 vaccination intention

Of the 1,537 participants, 1,105 expressed intention to accept COVID-19 vaccine, corresponding to a weighted proportion of 63.5% (95% CI: 59.0–68.1), whereas 432 participants, with a weighted proportion of 36.5% (95% CI: 31.9–41.0) reported intention to reject COVID-19 vaccine. Table 3 presents the absolute numbers and weighted proportions of participants’ COVID-19 vaccination intention by key characteristics. Intention to accept COVID-19 vaccine differed significantly by IDPs’ marital status, household distance to the nearest health facility, and COVID-19-related knowledge. Additionally, intention to accept vaccine among the IDPs varied significantly by perceived susceptibility to COVID-19, perceived severity of COVID-19, and perceived effectiveness of COVID-19 vaccine.

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Table 3. COVID-19 vaccination intention by key participants’ characteristics.

https://doi.org/10.1371/journal.pone.0308139.t003

Reasons for intention to reject COVID-19 vaccine

Of the 432 participants who reported intention to reject COVID-19 vaccine, 110, corresponding to a weighted proportion of 42.8% (95% CI: 34.9–50.6), did not provide any reason for their intention to reject the vaccine. However, 35.3% (95% CI: 27.7–42.9) gave reasons related to myths, misconceptions, and misinformation, 9.5% (95% CI: 5.0–13.9) expressed fear and concerns about vaccine safety and side effects, while 7.4% (95% CI: 3.3–11.4) felt no need for COVID-19 vaccination (Table 4).

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Table 4. Reasons for intention to reject COVID-19 vaccine.

https://doi.org/10.1371/journal.pone.0308139.t004

Factors associated with intention to accept COVID-19 vaccine

Table 5 shows the results of the weighted crude and multivariable logistic regression analysis of factors associated with intention to accept COVID-19 vaccine. At crude analysis, marital status, COVID-19-related knowledge, perceived susceptibility to COVID-19, perceived severity of COVID-19, and perceived effectiveness of COVID-19 vaccine demonstrated significant positive association with intention to accept COVID-19 vaccine. In contrast, household distance to the nearest health facility was negatively associated with intention to accept vaccine. Adjusting for co-variates at multivariable logistic regression analysis, IDPs who perceived COVID-19 as a severe illness compared to those who did not (Adjusted Odds Ratio (AOR) = 2.31, [95% CI: 1.35–3.96]), and IDPs who perceived COVID-19 vaccine as effective compared to those who did not (AOR = 4.28, [95% CI: 2.46–7.44]), irrespective of whether they resided in formal or informal camps, were significantly more likely to accept COVID-19 vaccine. Furthermore, IDPs who resided in formal (official) camps compared to those who resided in informal (unofficial) camps (AOR = 3.29, [95% CI: 1.94–5.56]) were significantly more likely to accept COVID-19 vaccine. However, IDPs who resided 2 kilometers or farther from the nearest health facility (AOR = 0.34, [95% CI: 0.20–0.58]) were less likely to accept vaccine.

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Table 5. Results of weighted logistic regression analysis of factors associated with intention to accept COVID-19 vaccine.

https://doi.org/10.1371/journal.pone.0308139.t005

Discussion

In this cross-sectional study, we investigated COVID-19 vaccination intention among unvaccinated IDPs in Northeast Nigeria and identified the factors associated with intention to accept COVID-19 vaccine as a protective measure against severe disease. The study provides epidemiological evidence to improve COVID-19 vaccination uptake, particularly among crisis-affected, vulnerable populations in complex humanitarian emergency contexts. Study participants were mostly females, unemployed, had no formal education, and predominantly resided in households that earned less than 30 US dollars income per month. Nearly two-thirds of the IDPs expressed intention to accept COVID-19 vaccine. Whereas perception of COVID-19 severity, perception of COVID-19 vaccine effectiveness, and status of IDPs camps were positively associated with intention to accept COVID-19 vaccine, household distance to the nearest health facility was negatively associated with intention to accept vaccine.

About 64% of IDPs in this study expressed intention to accept COVID-19 vaccine. This proportion is higher than the COVID-19 vaccination acceptance rate of 56.7% reported among migrants, refugees, and foreign workers in a systematic review and meta-analysis [48], but lower than 89.6% obtained among Syrian refugees in Jordan [49], 70.3% reported among refugees in the United States [50], and 70% reported among migrant and refugee groups in a systematic review and meta-analysis [51]. Compared to other populations, our result is similar to the figure obtained among the general population in China (63.3%), but lower than those reported among Bangladeshi adults (74.6%), Pakistani university students (72.5%), and the general population in Northwest Nigeria (72.4%) [23, 24, 52, 53]. Although the COVID-19 vaccination population proportion required to achieve herd immunity is still a subject of scientific debate, the proportion of IDPs in our study with the intention to accept vaccine fell short of a minimum of 90% vaccination proportion reported by some global health experts [54, 55]. Additionally, prior research have shown that the proportion of individuals with the intention to accept vaccine is usually lower than the eventual vaccination coverage [56, 57]. Presumably, the foregoing narrative indicates a gap in COVID-19 vaccination acceptance among the IDPs and underscores the need for targeted interventions to improve vaccination acceptance and uptake among this high-risk population.

Among the IDPs who would reject COVID-19 vaccine in this study, more than half gave reasons related to COVID-19 myths and misconceptions, concerns about vaccine safety and side effects, and no felt need as the justifications for their intention to reject vaccine, similar to findings reported by other authors [27, 58, 59]. Our results reflect the pervasive misinformation and erroneous beliefs regarding COVID-19 and COVID-19 vaccine at national and global scenes. For instance, COVID-19 was regarded as a hoax in many quarters across the world [60], while several individuals, particularly in sub-Saharan Africa, believe that COVID-19 was a ploy to reduce the world’s population [61]. Moreover, the safety and effectiveness of COVID-19 vaccine were subject of intense controversy among several population subgroups worldwide [62, 63]. Importantly, about 43% of IDPs who intend to reject vaccine provided no reason for their standpoint. We posit that understanding the reasons for vaccine rejection will guide evidence-based interventions to address its root cause and improve vaccination acceptance among this population. In this regard, we suggest a qualitative inquiry to gain a deeper insight into the reasons for intention to reject COVID-19 vaccine in this context.

Our study indicated that IDPs who perceived COVID-19 as severe were significantly more likely to accept COVID-19 vaccine compared to those who did not, similar to the findings of other studies [64, 65]. This result aligns with the underlying constructs of the Health Belief Model, the Protection Motivation Theory, and several other models of health behavior [66, 67]. Fundamentally, when individuals perceive a disease (or other health conditions) as severe, they eagerly strive to overcome various forms of physical and socio-cultural impediments so as to access preventive and therapeutic care to maintain health and well-being. Given that less than half (43.2%) of the IDPs in the current study perceived COVID-19 as severe, our result provides the basis for health authorities to ramp up context-specific, culturally appropriate COVID-19 educational and risk communication activities tailored to the needs of the IDPs to shape disease risk perception and promote informed decision-making on COVID-19 vaccination among this population to increase vaccination acceptance and uptake.

We demonstrated that IDPs who perceived COVID-19 vaccine as effective compared to those who did not were significantly more likely to accept COVID-19 vaccine. This result is consistent with the findings of previous research conducted in Ethiopia, Ghana, and Nigeria [26, 28, 68]. Existing literature indicates that perceived vaccine effectiveness (response efficacy) motivates individuals’ adoption of COVID-19 protective health behavior, including vaccination acceptance and uptake to avert COVID-19 threats [69]. Despite the widespread controversy and misinformation regarding the safety and effectiveness of COVID-19 vaccine among the general public [70], several authors have reported that perceived COVID-19 vaccine effectiveness is a major antidote to vaccine hesitancy [71, 72]. Furthermore, previous research have shown that providing information on COVID-19 vaccine effectiveness improves vaccination acceptance and uptake [73]. Seemingly, this evidence favors the feasibility of enhancing COVID-19 vaccination uptake by crafting and disseminating tailored information, education, and communication (IEC) messages to particularly emphasize the effectiveness of the COVID-19 vaccine, as documented in the published literature [74, 75].

Furthermore, IDPs who resided in formal (official) camps were significantly more likely to accept COVID-19 vaccine compared to those who resided in informal (unofficial) camps. Typically, formal camps in our study setting are officially recognized by the Government agencies responsible for emergency management and humanitarian affairs. As such, IDPs who reside in formal camps apparently benefit from healthcare, social, and other humanitarian support from Governmental and Non-Governmental Organizations (NGOs). For instance, with the support of Governmental agencies and NGOs, many health facilities in formal camps offer basic health care services, antenatal care, immunization, and other health interventions at a free or heavily subsidized cost. Moreover, facilities in formal camps served as the programmatic hubs for the planning and implementation of COVID-19 pandemic response interventions, including IEC activities, COVID-19 vaccination, case detection and reporting, among others. We believe that the facilitated access of IDPs in formal camps to COVID-19 vaccination, as well as their exposure to COVID-19 IEC at the health facilities, could partly explain their higher likelihood to accept COVID-19 vaccine compared to IDPs residing in informal camps.

Our study revealed an inverse association between household distance to health facility and intention to accept vaccine. We presume that this finding is partly related to the perceived financial challenges confronting the IDPs. For instance, about 85% of households in this study earn less than 30 US dollars per month. With this paltry income, it is possible that a large number of IDPs might not be able to afford the cost of transportation and logistics from remote areas to health facilities. We opine that this factor could negatively influence vaccination intention among this population and probably explain the observed inverse association between household distance to health facilities and intention to accept vaccine. Our result resonates with the findings of previous research, which identified distance as a major barrier to the uptake of vaccination and other healthcare services at health facilities among the general population [7679]. Furthermore, IDPs who reside farther from health facilities could have limited access to facility-driven IEC activities about COVID-19 and COVID-19 vaccine. Therefore, it is important for local health authorities to prioritize IDPs residing farther from health facilities for COVID-19 IEC activities to create awareness and improve vaccination acceptance. Moreover, appropriate interventions, such as a mobile vaccination strategy to reach and deliver vaccines to IDPs in remote households, should be implemented and/or ramped up.

This study draws strength from at least two key methodological considerations. Firstly, the IDPs studied were recruited via a stratified sampling approach. Based on existing literature, this sampling approach probably increased the precision of the statistical estimates obtained in our study [80]. Secondly, we performed complex survey data analysis, incorporating survey weights to obtain weighted statistical estimates and confidence intervals. We believe that this weighted data analysis approach likely enhances the validity and generalizability of the study findings. However, we recognize certain limitations of this study. Data for the study were mostly retrospective and self-reported. As such, we admit that the potential for recall bias and misinformation cannot be ruled out. Additionally, we recognize a limitation regarding the scope of the study; including a qualitative component in the study would have expanded its scope and provided additional insights, particularly into the reasons for vaccine rejection.

Conclusions

As the global health community consolidates the gains of COVID-19 pandemic control, our study provides evidence to improve COVID-19 vaccination acceptance among IDPs in Northeast Nigeria. About two-thirds of these IDPs expressed intention to accept COVID-19 vaccine. Misconceptions, vaccine safety concerns and no felt need were the prominent reasons for vaccine rejection. Perceived COVID-19 severity, perceived vaccine effectiveness, and residing in formal camps were positively associated with intention to accept COVID-19 vaccine. However, household distance from the nearest health facility demonstrated a negative association with intention to accept vaccine. The study underscores the need for local health authorities and other relevant stakeholders to ramp up context-specific, culturally appropriate COVID-19 health education, risk communication, and public enlightenment activities tailored to the needs of the IDPs to counter misinformation, correct misconceptions, shape disease risk perception, strengthen vaccine confidence and promote informed-decision making on COVID-19 vaccination, particularly among IDPs in unofficial camps. Authorities should implement or ramp up appropriate interventions, including mobile vaccination strategy to deliver vaccines to IDPs residing in remote households. Further qualitative research should deep dive into the reasons for vaccination rejection to permit a better understanding of this phenomenon.

Supporting information

S2 File. Assessment algorithm for COVID-19 related knowledge.

https://doi.org/10.1371/journal.pone.0308139.s003

(PDF)

S3 File. List of items used to assess perceived COVID-19 susceptibility, severity, and vaccine effectiveness.

https://doi.org/10.1371/journal.pone.0308139.s004

(PDF)

S1 Data. Research data underlying the findings reported in the manuscript.

https://doi.org/10.1371/journal.pone.0308139.s005

(XLSX)

Acknowledgments

The authors acknowledge the effort and support of the Ministries of Health of Borno, Adamawa, and Yobe States. We appreciate the leadership of our study IDPs camps and health partner organizations in these states. Additionally, we sincerely acknowledge Adam Attahiru, Toman Emmanuel, Alhaji Dalatu, Musa Ashafa, Hassan Umar Kamfut, Fatima Mohammed El-Yakub, Ahmed Gambo Ibbi, and Bulama Maina Yaro for their technical support.

References

  1. 1. Mohan B, Vinod N. COVID-19: An Insight into SARS-CoV2 Pandemic Originated at Wuhan City in Hubei Province of China. J Infect Dis Epidemiol. 2020 Jul 18;6(4):146.
  2. 2. Cucinotta D, Vanelli M. WHO Declares COVID-19 a Pandemic. Acta Bio Medica Atenei Parm. 2020;91(1):157–60. pmid:32191675
  3. 3. WHO Coronavirus (COVID-19) Dashboard [Internet]. [cited 2023 Mar 27]. Available from: https://covid19.who.int
  4. 4. Chanda-Kapata P, Ntoumi F, Kapata N, Lungu P, Mucheleng’anga LA, Chakaya J, et al. Tuberculosis, HIV/AIDS and Malaria Health Services in sub-Saharan Africa–A Situation Analysis of the Disruptions and Impact of the COVID-19 Pandemic. Int J Infect Dis [Internet]. 2022 Mar 25 [cited 2022 Oct 17]; Available from: https://www.sciencedirect.com/science/article/pii/S1201971222001734
  5. 5. Ota MOC, Badur S, Romano-Mazzotti L, Friedland LR. Impact of COVID-19 pandemic on routine immunization. Ann Med. 53(1):2286–97. pmid:34854789
  6. 6. Harris Emily. WHO Declares End of COVID-19 Global Health Emergency. JAMA. 2023 Jun 6;329(21):1817–1817.
  7. 7. Nigeria Centre for Disease Control and Prevention. An update of COVID-19 outbreak in Nigeria [Internet]. [cited 2024 Jun 22]. Available from: https://ncdc.gov.ng/diseases/sitreps/?cat=14&name=An%20update%20of%20COVID-19%20outbreak%20in%20Nigeria
  8. 8. World Health Organization. COVID-19 vaccines | WHO COVID-19 dashboard [Internet]. datadot. [cited 2024 Mar 17]. Available from: https://data.who.int/dashboards/covid19/vaccines
  9. 9. Sawn Khai T. Higher risk of COVID-19 infection among internally displaced persons (IDPs) in Myanmar under the military coup. Glob Public Health. 2022 Dec;17(12):3967–71. pmid:35042432
  10. 10. Deng Francis M. Guiding Principles on Internal Displacement. Int Migr Rev. 1999 Jun 1;33(2):484–93.
  11. 11. International Organization for Migration (IOM), Mar 21 2022. DTM Nigeria—North-east—Displacement Report 40 (March 2022). IOM, Nigeria.
  12. 12. Wamala JF, Loro F, Deng SJ, Berta KK, Guyo AG, Mpairwe A, et al. Epidemiological characterization of COVID-19 in displaced populations of South Sudan. Pan Afr Med J. 2022 Jun 9;42(Suppl 1):4. pmid:36158931
  13. 13. Khouzam A, Verma M. Internal Displacement and COVID-19: Taking Stock and Looking Forward. Refug Surv Q. 2021 Jan 7;39(4):591–601.
  14. 14. Ahmed MAA, Ly BA, Diarra NH, Traore FB, Diarra D, Kande IF, et al. Challenges to the implementation and adoption of physical distancing measures against COVID-19 by internally displaced people in Mali: a qualitative study. Confl Health. 2021 Dec 4;15(1):88. pmid:34863236
  15. 15. Ly BA, Ahmed MAA, Traore FB, Diarra NH, Dembele M, Diarra D, et al. Challenges and difficulties in implementing and adopting isolation and quarantine measures among internally displaced people during the COVID-19 pandemic in Mali (161/250). J Migr Health. 2022 Jan 1;5:100104. pmid:35434677
  16. 16. Wise Jacqui. Covid-19: WHO declares end of global health emergency. BMJ. 2023 May 9;381:p1041. pmid:37160309
  17. 17. World Health Organization. Vaccine efficacy, effectiveness and protection [Internet]. Vaccine efficacy, effectiveness and protection. 2021 [cited 2023 Aug 28]. Available from: https://www.who.int/news-room/feature-stories/detail/vaccine-efficacy-effectiveness-and-protection
  18. 18. Ullah I, Khan KS, Tahir MJ, Ahmed A, Harapan H. Myths and conspiracy theories on vaccines and COVID-19: Potential effect on global vaccine refusals. Vacunas. 2021 May 1;22(2):93–7. pmid:33727904
  19. 19. Wonodi C, Obi-Jeff C, Adewumi F, Keluo-Udeke SC, Gur-Arie R, Krubiner C, et al. Conspiracy theories and misinformation about COVID-19 in Nigeria: Implications for vaccine demand generation communications. Vaccine. 2022 Mar 18;40(13):2114–21. pmid:35153088
  20. 20. Mengistu DA, Demmu YM, Asefa YA. Global COVID-19 vaccine acceptance rate: Systematic review and meta-analysis. Front Public Health. 2022;10:1044193. pmid:36568768
  21. 21. Olu-Abiodun O, Abiodun O, Okafor N. COVID-19 vaccination in Nigeria: A rapid review of vaccine acceptance rate and the associated factors. PLOS ONE. 2022 May 11;17(5):e0267691. pmid:35544545
  22. 22. Gidado S, Musa M, Ba’aba AI, Francis MR, Okeke LA, Bukar FL, et al. Knowledge, risk perception and uptake of COVID-19 vaccination among internally displaced persons in complex humanitarian emergency setting, Northeast Nigeria. BMC Public Health. 2024 Feb;24(1):1–16.
  23. 23. Abedin M, Islam MA, Rahman FN, Reza HM, Hossain MZ, Hossain MA, et al. Willingness to vaccinate against COVID-19 among Bangladeshi adults: Understanding the strategies to optimize vaccination coverage. PLOS ONE. 2021 Apr 27;16(4):e0250495. pmid:33905442
  24. 24. Song S, Zang S, Gong L, Xu C, Lin L, Francis MR, et al. Willingness and uptake of the COVID-19 testing and vaccination in urban China during the low-risk period: a cross-sectional study. BMC Public Health. 2022 Dec;22(1):556. pmid:35313843
  25. 25. Wong EL yi Qiu H, Chien WT, lee Wong JC, Chalise HN, xuan Hoang HT, et al. COVID-19 Vaccine Willingness and Related Factors Among Health Care Workers in 3 Southeast Asian Jurisdictions. JAMA Netw Open. 2022 Aug 22;5(8):e2228061. pmid:35994284
  26. 26. Adejumo OA, Ogundele OA, Madubuko CR, Oluwafemi RO, Okoye OC, Okonkwo KC, et al. Perceptions of the COVID-19 vaccine and willingness to receive vaccination among health workers in Nigeria. Osong Public Health Res Perspect. 2021 Aug 31;12(4):236–43. pmid:34289295
  27. 27. Aklil MB, Temesgan WZ, Gessesse DN, Kassa BG, Tiguh AE, Kebede AA, et al. Willingness to Receive COVID-19 Vaccine and Associated Factors Among College Students in Gondar City, Northwest Ethiopia. Front Educ [Internet]. 2022 [cited 2023 Aug 26];7. Available from: https://www.frontiersin.org/articles/10.3389/feduc.2022.799301
  28. 28. Tegegne MD, Girma S, Mengistu S, Mesfin T, Adugna T, Kokeb M, et al. Willingness to receive COVID-19 vaccine and associated factors among adult chronic patients. A cross-sectional study in Northwest Ethiopia. PLOS ONE. 2022 Jul 12;17(7):e0269942. pmid:35819959
  29. 29. Al-Hanawi MK, Ahmad K, Haque R, Keramat SA. Willingness to receive COVID-19 vaccination among adults with chronic diseases in the Kingdom of Saudi Arabia. J Infect Public Health. 2021 Oct 1;14(10):1489–96. pmid:34417135
  30. 30. Yoda T, Katsuyama H. Willingness to Receive COVID-19 Vaccination in Japan. Vaccines. 2021 Jan 14;9(1):48. pmid:33466675
  31. 31. Kohrt BA, Mistry AS, Anand N, Beecroft B, Nuwayhid I. Health research in humanitarian crises: an urgent global imperative. BMJ Glob Health. 2019;4(6):e001870. pmid:31798999
  32. 32. National Population Commission. Nigeria Population Projections and Demographic Indicators [Internet]. [cited 2024 Jun 22]. Available from: https://nationalpopulation.gov.ng/publications
  33. 33. IOM UN Migration. IOM Displacement Tracking Matrix (DTM) North-East Nigeria | Displacement Report Round 40. 2022.
  34. 34. Salem MR, Hanafy SHA, Bayad AT, Abdel-aziz SB, Shaheen D, Amin TT. Assessment of knowledge, attitudes, and precautionary actions against COVID-19 among medical students in Egypt. J Infect Public Health. 2021 Oct 1;14(10):1427–34. pmid:34426094
  35. 35. Lee M, Kang BA, You M. Knowledge, attitudes, and practices (KAP) toward COVID-19: a cross-sectional study in South Korea. BMC Public Health. 2021 Dec;21(1):295. pmid:33546644
  36. 36. Getawa S, Aynalem M, Bayleyegn B, Adane T. Knowledge, attitude and practice towards COVID-19 among secondary school students in Gondar town, Northwest Ethiopia. PLOS ONE. 2022 May 23;17(5):e0268084. pmid:35604938
  37. 37. Rubin RB, Rubin AM, Graham E, Perse EM, Seibold D. Risk Behavior Diagnosis (RBD) Scale. In: Communication Research Measures II. Routledge; 2010. p. 345–8.
  38. 38. Gliem JA, Gliem RR. Calculating, interpreting, and reporting Cronbach’s alpha reliability coefficient for Likert-type scales. In: Midwest research-to-practice conference in adult, continuing, and community education. Columbus, OH; 2003. p. 82–7.
  39. 39. Gould GS, Watt K, Cadet-James Y, Clough AR. Using the risk behaviour diagnosis scale to understand Australian Aboriginal smoking—A cross-sectional validation survey in regional New South Wales. Prev Med Rep. 2015 Jan 1;2:4–9. pmid:26844043
  40. 40. Rimal Rajiv N. Perceived Risk and Self-Efficacy as Motivators: Understanding Individuals’ Long-Term Use of Health Information. J Commun. 2001;51(4):633–54.
  41. 41. Ciol MA, Hoffman JM, Dudgeon BJ, Shumway-Cook A, Yorkston KM, Chan L. Understanding the use of weights in the analysis of data from multistage surveys. Arch Phys Med Rehabil. 2006;87(2):299–303. pmid:16442990
  42. 42. Lumley Thomas. Analysis of Complex Survey Samples. J Stat Softw [Internet]. 2004 [cited 2023 Aug 8];9(8), 1–19. Available from: http://www.jstatsoft.org/v09/i08/
  43. 43. Kim JH. Multicollinearity and misleading statistical results. Korean J Anesthesiol. 2019 Dec;72(6):558–69. pmid:31304696
  44. 44. Cavanaugh JE, Neath AA. The Akaike information criterion: Background, derivation, properties, application, interpretation, and refinements. WIREs Comput Stat. 2019 May 1;11(3):e1460.
  45. 45. R Core Team. R: A Language and Environment for Statistical Computing [Internet]. R Foundation for Statistical Computing, Vienna, Austria; 2022. Available from: https://www.R-project.org/
  46. 46. World Medical Association. World Medical Association Declaration of Helsinki: ethical principles for medical research involving human subjects. JAMA. 2013 Nov 27;310(20):2191–4. pmid:24141714
  47. 47. O’Mathúna D. Research ethics in the context of humanitarian emergencies. J Evid-Based Med. 2015;8(1):31–5. pmid:25594722
  48. 48. Hajissa K, Mutiat HA, Kaabi NA, Alissa M, Garout M, Alenezy AA, et al. COVID-19 Vaccine Acceptance and Hesitancy among Migrants, Refugees, and Foreign Workers: A Systematic Review and Meta-Analysis. Vaccines. 2023;11(6):1070. pmid:37376459
  49. 49. Talafha QM, Al-Haidose A, AlSamman AY, Abdallah SA, Istaiteyeh R, Ibrahim WN, et al. COVID-19 vaccine acceptance among vulnerable groups: Syrian refugees in Jordan. Vaccines. 2022;10(10):1634. pmid:36298498
  50. 50. Zhang M, Gurung A, Anglewicz P, Subedi P, Payton C, Ali A, et al. Acceptance of COVID-19 Vaccine Among Refugees in the United States. Public Health Rep. 2021 Nov 1;136(6):774–81. pmid:34546812
  51. 51. Alimoradi Z, Sallam M, Jafari E, Potenza MN, Pakpour AH. Prevalence of COVID-19 vaccine acceptance among migrant and refugee groups: A systematic review and meta-analysis. Vaccine X. 2023 Aug 1;14:100308.
  52. 52. Hossian M, Khan MAS, Nazir A, Nabi MH, Hasan M, Maliha R, et al. Factors affecting intention to take COVID-19 vaccine among Pakistani University Students. PLOS ONE. 2022 Feb 11;17(2):e0262305. pmid:35148317
  53. 53. Oche OM, Adamu H, Yahaya M, Illo HG, Danmadami AM, Ijapa A, et al. Perception and willingness to accept COVID-19 Vaccines: A cross-sectional survey of the general population of Sokoto State, Nigeria. PLOS ONE. 2022 Dec 1;17(12):e0278332. pmid:36454892
  54. 54. Pedro Plans-Rubió. Percentages of Vaccination Coverage Required to Establish Herd Immunity against SARS-CoV-2. Vaccines. 2022 May 8;10(5):736. pmid:35632492
  55. 55. Lucero-Prisno DE, Ogunkola IO, Esu EB, Adebisi YA, Lin X, Li H. Can Africa achieve herd immunity? Glob Health Res Policy. 2021 Dec 2;6(1):46. pmid:34852844
  56. 56. Kwon Y, Cho HY, Lee YK, Bae GR, Lee SG. Relationship between intention of novel influenza A (H1N1) vaccination and vaccination coverage rate. Vaccine. 2010 Dec 16;29(2):161–5. pmid:21055495
  57. 57. Wang C, Han B, Zhao T, Liu H, Liu B, Chen L, et al. Vaccination willingness, vaccine hesitancy, and estimated coverage at the first round of COVID-19 vaccination in China: A national cross-sectional study. Vaccine. 2021 May 18;39(21):2833–42. pmid:33896661
  58. 58. Nomura S, Eguchi A, Yoneoka D, Kawashima T, Tanoue Y, Murakami M, et al. Reasons for being unsure or unwilling regarding intention to take COVID-19 vaccine among Japanese people: A large cross-sectional national survey. Lancet Reg Health—West Pac. 2021 Sep;14:100223. pmid:34368797
  59. 59. López-Cepero A, Cameron S, Negrón LE, Colón-López V, Colón-Ramos U, Mattei J, et al. Uncertainty and unwillingness to receive a COVID-19 vaccine in adults residing in Puerto Rico: Assessment of perceptions, attitudes, and behaviors. Hum Vaccines Immunother. 2021 Oct 3;17(10):3441–9. pmid:34402409
  60. 60. Aiyewumi O, Okeke MI. The myth that Nigerians are immune to SARS-CoV-2 and that COVID-19 is a hoax are putting lives at risk. J Glob Health. 10(2):020375. pmid:33110566
  61. 61. Osuagwu UL, Miner CA, Bhattarai D, Mashige KP, Oloruntoba R, Abu EK, et al. Misinformation About COVID-19 in Sub-Saharan Africa: Evidence from a Cross-Sectional Survey. Health Secur. 2021 Feb 1;19(1):44–56. pmid:33606572
  62. 62. Hammad AM, Al-Qerem W, Abu Zaid A, Khdair SI, Hall FS. Misconceptions Related to COVID 19 Vaccines Among the Jordanian Population: Myth and Public Health. Disaster Med Public Health Prep.: 1–8. pmid:35673791
  63. 63. Chavda VP, Chen Y, Dave J, Chen ZS, Chauhan SC, Yallapu MM, et al. COVID-19 and vaccination: myths vs science. Expert Rev Vaccines. 2022 Nov 2;21(11):1603–20. pmid:35980281
  64. 64. Coe AB, Elliott MH, Gatewood SBS, Goode JVR, Moczygemba LR. Perceptions and predictors of intention to receive the COVID-19 vaccine. Res Soc Adm Pharm. 2022 Apr 1;18(4):2593–9. pmid:33994325
  65. 65. Wake AD. The willingness to receive COVID-19 vaccine and its associated factors:“vaccination refusal could prolong the war of this pandemic”–a systematic review. Risk Manag Healthc Policy. 2021;2609–23. pmid:34188572
  66. 66. Champion VL, Skinner CS. The health belief model. Health Behav Health Educ Theory Res Pract. 2008;4:45–65.
  67. 67. Norman P, Boer H, Seydel ER, Mullan B. Protection motivation theory. Predict Chang Health Behav Res Pract Soc Cogn Models. 2015;3:70–106.
  68. 68. Amo-Adjei J, Nurzhynska A, Essuman R, Lohiniva AL. Trust and willingness towards COVID-19 vaccine uptake: a mixed-method study in Ghana, 2021. Arch Public Health. 2022 Feb 21;80(1):64. pmid:35189963
  69. 69. Ezati Rad R, Mohseni S, Kamalzadeh Takhti H, Hassani Azad M, Shahabi N, Aghamolaei T, et al. Application of the protection motivation theory for predicting COVID-19 preventive behaviors in Hormozgan, Iran: a cross-sectional study. BMC Public Health. 2021 Mar 8;21(1):466. pmid:33685426
  70. 70. Lee SK, Sun J, Jang S, Connelly S. Misinformation of COVID-19 vaccines and vaccine hesitancy. Sci Rep. 2022 Aug 11;12(1):13681. pmid:35953500
  71. 71. Marzo RR, Ahmad A, Islam MS, Essar MY, Heidler P, King I, et al. Perceived COVID-19 vaccine effectiveness, acceptance, and drivers of vaccination decision-making among the general adult population: A global survey of 20 countries. PLoS Negl Trop Dis. 2022 Jan;16(1):e0010103. pmid:35089917
  72. 72. Adane M, Ademas A, Kloos H. Knowledge, attitudes, and perceptions of COVID-19 vaccine and refusal to receive COVID-19 vaccine among healthcare workers in northeastern Ethiopia. BMC Public Health. 2022 Jan 18;22(1):128.
  73. 73. Davis CJ, Golding M, McKay R. Efficacy information influences intention to take COVID‐19 vaccine. Br J Health Psychol. 2022;27(2):300–19. pmid:34250684
  74. 74. Chirico F, da Silva JAT, Tsigaris P, Sharun K. Safety & effectiveness of COVID-19 vaccines: A narrative review. Indian J Med Res. 2022 Jan;155(1):91–104.
  75. 75. Zheng C, Shao W, Chen X, Zhang B, Wang G, Zhang W. Real-world effectiveness of COVID-19 vaccines: a literature review and meta-analysis. Int J Infect Dis. 2022 Jan;114:252–60. pmid:34800687
  76. 76. Sato Ryoko. Association between access to a health facility and continuum of vaccination behaviors among Nigerian children. Hum Vaccines Immunother. 2020 May 3;16(5):1215–20. pmid:31634047
  77. 77. Awoyemi TT, Obayelu OA, Opaluwa HI. Effect of Distance on Utilization of Health Care Services in Rural Kogi State, Nigeria. J Hum Ecol. 2011 Jul 1;35(1):1–9.
  78. 78. Dotse-Gborgbortsi W, Nilsen K, Ofosu A, Matthews Z, Tejedor-Garavito N, Wright J, et al. Distance is “a big problem”: a geographic analysis of reported and modelled proximity to maternal health services in Ghana. BMC Pregnancy Childbirth. 2022 Aug 31;22(1):672. pmid:36045351
  79. 79. Steinbrook E, Min MC, Kajeechiwa L, Wiladphaingern J, Paw MK, Pimanpanarak MPJ, et al. Distance matters: barriers to antenatal care and safe childbirth in a migrant population on the Thailand-Myanmar border from 2007 to 2015, a pregnancy cohort study. BMC Pregnancy Childbirth. 2021 Dec 2;21(1):802. pmid:34856954
  80. 80. Forthofer RN, Lee ES, Hernandez M. 15—Analysis of Survey Data. In: Forthofer RN, Lee ES, Hernandez M, editors. Biostatistics (Second Edition) [Internet]. San Diego: Academic Press; 2007. p. 421–43. Available from: https://www.sciencedirect.com/science/article/pii/B9780123694928500200