Determinants Of Adult And Adolescent Vaccination: A Review Of Behavioural, Structural, And Economic Factors

Vaccination stands as one of the most successful and cost-effective public health interventions in modern history, preventing an estimated 2–3 million deaths annually and dramatically reducing the global burden of infectious diseases(1). Despite remarkable progress in childhood immunization programmes worldwide, vaccination coverage among adolescents and adults remains persistently suboptimal in many regions, leaving significant portions of the population vulnerable to vaccine-preventable diseases such as influenza, human papillomavirus (HPV), tetanus, diphtheria, pertussis, pneumococcal disease, and herpes zoster(1) .

The COVID-19 pandemic starkly illuminated these gaps, as vaccine uptake varied dramatically across age groups and geographic regions, with adolescents and adults exhibiting lower vaccination rates compared to routine childhood immunization programmes(2). Recent data from the World Health Organization indicate that while global childhood vaccination coverage has stabilized at approximately 81% for the third dose of diphtheria-tetanus-pertussis (DTP3) vaccine, coverage for adolescent and adult vaccines such as HPV (complete series) remains below 15% in many low- and middle-income countries, and seasonal influenza vaccination among high-risk adults rarely exceeds 50% even in high-income settings(1,3).

Understanding why adolescents and adults fail to receive recommended vaccines requires examination of multiple interconnected determinants. Behavioural factors—including vaccine hesitancy, exposure to misinformation, fear of adverse effects, low perceived susceptibility to vaccine-preventable diseases, and mistrust in healthcare systems—have been consistently identified as significant barriers to vaccination(4,5). Social and psychological influences, such as community norms, cultural beliefs, and the rapid proliferation of anti-vaccine content through digital media platforms, further erode vaccine confidence(6,7). Structural barriers, including inadequate healthcare infrastructure, limited vaccine supply chain capacity, geographic disparities in service access, inconvenient clinic hours, and fragmented immunization registries, continue to impede uptake, particularly among rural, migrant, and marginalised populations(2,8). Economic constraints—comprising direct vaccine costs, consultation fees, transportation expenses, and indirect losses such as wages forfeited during healthcare visits—disproportionately affect low-income groups and contribute to persistent inequities in vaccination coverage across the life course(9).

The COVID-19 pandemic exacerbated these challenges, disrupting routine immunization services in at least 68 countries and leaving an estimated 23 million children and countless adolescents and adults without scheduled vaccines in 2020 alone(2). This disruption has reinforced the urgent need for robust, evidence-based life-course immunization strategies that address the full spectrum of behavioural, structural, and economic determinants.

Therefore, this review aims to systematically synthesise existing evidence on the behavioural, structural, and economic determinants influencing vaccination uptake among adolescents and adults, and to provide evidence-based recommendations for improving vaccine acceptance, accessibility, and equity(10).

Key Data

Summary of Visual Evidence

The three visual elements presented above collectively demonstrate:

1. Conceptual framework (Figure 1): Behavioural, structural, and economic determinants are interconnected, and multi-component interventions are required to address them simultaneously.
2. Intervention effectiveness (Figure 2): Multi-component and community-engaged interventions show the largest coverage improvements (median +19% to +22%), while single-modality interventions (e.g., reminders alone) show more modest effects (+9% to +12%).
3. Persistent disparities (Figure 3, Table 1): Geographic, ethnic, and income-based disparities persist across high- and low-income settings, underscoring the need for equity-focused strategies.

DISCUSSION

Principal Findings

This systematic synthesis of 46 studies examining vaccination uptake among adolescents and adults provides compelling evidence that behavioural, structural, and economic determinants interact in complex ways to shape vaccination coverage across diverse populations and settings. The findings reveal several consistent patterns. First, vaccine hesitancy—driven by low perceived risk, safety concerns, religious beliefs, and inadequate knowledge—remains a pervasive behavioural barrier across high-, middle-, and low-income countries(11–13). Second, structural barriers including geographic disparities, exclusion of migrant and homeless populations, fragmented school-based delivery systems, and limited provider access consistently undermine equitable vaccine distribution(18,21,23). Third, economic constraints—household income, out-of-pocket costs, and indirect expenses—disproportionately affect vulnerable populations, even in universal healthcare settings(29,31,33). Fourth, multi-component interventions that address multiple determinant categories simultaneously, including new media reminders, provider communication training, school-based process improvements, and community-engaged outreach, demonstrate the greatest effectiveness in improving uptake (24,35,39).

Interpretation of Behavioural Determinants

The consistent identification of vaccine hesitancy as a major barrier across diverse geographic and cultural contexts underscores the global nature of this challenge. Chuma and colleagues (2025) documented that low perceived risk, safety concerns, and lack of knowledge were associated with lower HPV vaccine uptake in Zimbabwe, while Pugliese-Garcia and colleagues (2018) found similar patterns in informal settlements in Zambia. Notably, Hansen and Pickering (2024) demonstrated that religious beliefs independently predicted COVID-19 vaccine uptake in England, suggesting that cultural and faith-based factors require tailored communication strategies rather than generic educational approaches.

The finding from Strupat and colleagues (2022) that perceived risk and trust in vaccine safety were strong predictors of willingness to take COVID-19 vaccination in Ethiopia highlights a critical insight: behavioural determinants are not static but responsive to contextual factors such as epidemic threat and media messaging. During the COVID-19 pandemic, risk perception was dynamically shaped by infection and mortality rates, yet vaccine hesitancy persisted in many settings due to misinformation and mistrust. This aligns with the observation by Farmanara and colleagues (2018) that low perceived susceptibility to influenza was consistently associated with non-vaccination among Canadian adults, indicating that even for well-established vaccines, perceived personal risk remains a modifiable behavioural target.

The role of parental and family beliefs, particularly concerning HPV vaccination, reveals unique behavioural barriers related to adolescent sexual health. Mayer and colleagues (2013) found that concerns about sexual disinhibition following HPV vaccination contributed to hesitancy among some parents, reflecting persistent misconceptions despite evidence refuting such associations. Similarly, Atkinson and colleagues (2024) reported that parental attitudes and previous vaccine behaviour were strong predictors of pediatric influenza vaccination, suggesting that behavioural interventions should target both caregivers and adolescents themselves.

Importantly, the behavioural drivers identified in these studies are not isolated but interact with structural and economic factors. For example, low knowledge about vaccine benefits may be more prevalent in populations with limited access to healthcare information(13), while mistrust may be amplified among historically marginalised groups who have experienced healthcare discrimination(25). This interdependence reinforces the need for integrated intervention strategies rather than purely behavioural or purely structural approaches.

Interpretation of Structural Barriers

The structural barriers identified across the 46 studies are remarkably consistent: geographic disparities, school-based delivery challenges, exclusion of migrant and homeless populations, fragmented data systems, and limited provider access. Baroutsou and colleagues (2022) documented significant regional variations in timely measles vaccination in Switzerland, with rural and remote areas showing lower coverage. Similarly, Preto and colleagues (2021) found substantial geographic variation in dengue vaccine uptake in Brazil associated with distance to vaccination centres. These findings echo the broader immunization literature and highlight that even in high-income countries with well-developed health systems, geography remains a structural determinant of vaccine access.

School-based vaccination programs, while effective in reaching adolescents, face structural challenges that limit their potential. Dubé and colleagues (2024) identified logistical barriers including consent form return processes, scheduling conflicts, and lack of dedicated clinic time as factors limiting HPV vaccine uptake in Canadian schools. Dionne and colleagues (2024) demonstrated that reminder systems and streamlined consent procedures significantly improved coverage, suggesting that relatively simple process modifications can yield meaningful gains. The HPV.edu study protocol described by Skinner and colleagues (2015) provides a rigorous framework for evaluating such logistical and educational interventions, though real-world implementation remains variable.

Migrant and refugee populations represent some of the most structurally disadvantaged groups in vaccination coverage. Giambi and colleagues (2019) found that fragmented data systems, language barriers, and lack of tailored outreach were major structural barriers in six European countries. Faijue and colleagues (2026) systematically reviewed catch-up vaccination strategies for migrants in LMICs, identifying that lack of legal documentation, mobility constraints, and exclusion from routine immunization systems were consistently associated with undervaccination. These findings are particularly concerning given that migrants often originate from settings with lower baseline coverage and may face increased infectious disease risks during displacement and resettlement. The absence of standardised data collection on migrant vaccination status across many national systems represents a critical evidence gap that impedes targeted intervention.

People experiencing homelessness and Indigenous populations face analogous structural barriers. Thomas and Mackie (2023) reported substantially lower COVID-19 vaccination coverage among homeless populations in Wales, with lack of fixed address for registration and limited primary care access identified as key obstacles. Eurich and colleagues (2025) described data fragmentation and lack of culturally appropriate services as barriers for First Nations people in Alberta. These findings underscore that structural barriers are not uniform across populations but are shaped by specific historical, legal, and service delivery contexts. Interventions that have proven effective in one setting—such as community-based outreach and mobile vaccination teams(26,27)—may require adaptation to be effective in others.

The expansion of provider roles, such as including pharmacists as immunizers, has emerged as a structural facilitator. Isenor and colleagues (2018) demonstrated that this policy change significantly increased influenza vaccination coverage in Nova Scotia by improving access and convenience. This finding supports the broader movement toward task shifting and multi-site vaccination delivery, though implementation varies across jurisdictions and vaccine types.

Interpretation of Economic Determinants

Economic constraints consistently predict lower vaccination uptake across studies, regardless of national income level. Saha and colleagues (2018) found that lower household income, food insecurity, and lack of formal employment were significantly associated with lower cholera vaccine uptake in Bangladesh. Dhalaria and colleagues (2024) reported that economic vulnerability and unintended pregnancy were associated with complete non-vaccination in India. Even in high-income settings with universal healthcare, socioeconomic gradients persist: Quach and colleagues (2012) and Kroneman and van Essen (2007) both documented lower influenza vaccine uptake among lower-income groups in Canada and Sweden, respectively.

These persistent economic gradients suggest that financial barriers extend beyond direct vaccine costs. Even when vaccines are provided free of charge, indirect costs—transportation, time off work, childcare for accompanying children—remain prohibitive for low-income families. Schaetti and colleagues (2012) demonstrated that provision of transport reimbursement significantly improved participation in mass vaccination campaigns in Zanzibar, providing direct evidence that addressing indirect economic barriers is effective. Ladner and colleagues (2014) found that fully subsidized HPV vaccination programs in LMICs achieved higher uptake than those requiring out-of-pocket payment, reinforcing the importance of removing all financial barriers.

Notably, economic determinants interact with structural and behavioural factors. Low-income populations often face greater geographic barriers (fewer nearby vaccination sites, poorer public transport), have less flexible work schedules that conflict with clinic hours, and may have lower health literacy due to educational disparities. This clustering of disadvantage means that interventions addressing only one dimension—for example, reducing vaccine cost without improving access—are unlikely to fully close coverage gaps.

Intervention Effectiveness and Implications for Practice

The intervention studies synthesised in this review provide actionable guidance for policymakers and practitioners. Odone and colleagues (2015) found that new media interventions—text message reminders, social media campaigns, and mobile applications—are effective in increasing vaccine uptake. Zoni and colleagues (2019) demonstrated that SMS reminders significantly increased influenza vaccination rates among cystic fibrosis patients, while Gilano and colleagues (2025) reported that mHealth interventions improved childhood vaccination coverage in Ethiopia. These findings suggest that digital interventions are scalable and cost-effective, particularly in settings with high mobile phone penetration. However, implementation must be careful to avoid exacerbating digital divides, as older adults, low-income populations, and those in remote areas may have limited access to smartphones or reliable internet.

Provider communication strategies are another critical intervention lever. Malo and colleagues (2018) found that announcement training—where providers state the recommendation directly without extensive discussion—resulted in higher HPV vaccination acceptance compared to conversation-based approaches. This counterintuitive finding suggests that for certain vaccines, decisional conflict may be reduced by clear, authoritative recommendations rather than lengthy shared decision-making. Cartmell and colleagues (2018) similarly reported that provider recommendation quality and consistency were critical facilitators for HPV vaccination. These findings have important implications for provider training programmes, which have historically emphasized open-ended conversation over presumptive announcements.

School-based interventions have demonstrated effectiveness for HPV vaccination. Ou and Youngstedt (2022) systematically reviewed interventions for college-aged populations, finding that educational interventions, reminder systems, and on-campus vaccination clinics increased uptake. Dionne and colleagues (2024) showed that reminder systems and streamlined consent procedures improved coverage in Quebec schools. However, the effectiveness of school-based programs depends on addressing structural barriers such as consent form return logistics, which disproportionately affect families with limited literacy or English proficiency.

For migrant, refugee, and homeless populations, community-engaged and adaptive approaches appear most promising. Faijue and colleagues (2026) identified community-based outreach, culturally tailored education, and removal of administrative barriers as effective components. Pavoncello and colleagues (2025) demonstrated that flexible, community-engaged strategies responding to real-time feedback significantly improved COVID-19 vaccine coverage in Madagascar. Sangwe and colleagues (2024) showed that community-oriented primary care generated vaccine demand in a remote fishing community in Cameroon. These studies share a common theme: effective interventions for structurally marginalised populations require trust-building, linguistic and cultural adaptation, and delivery through trusted local partners rather than top-down mass campaigns.

Interventions for pregnant women have also shown effectiveness, with Wong and colleagues (2016) finding that healthcare provider recommendation, patient education, and reminder systems were effective, and multi-component interventions showing the greatest impact. This aligns with the broader principle that vaccination promotion is most effective when multiple barriers are addressed simultaneously.

Comparison with Life-Course Immunisation Frameworks

The findings of this synthesis strongly support the life-course approach to immunisation advocated by Seale and colleagues (2022). They argued that fragmented systems and lack of adult vaccination registries are structural barriers requiring policy attention. The present review extends this by documenting that behavioural, structural, and economic barriers vary across the life course. For adolescents, school-based delivery and parental consent processes are unique structural factors. For young adults, transition out of pediatric care and into adult systems often results in vaccination discontinuation. For pregnant women, antenatal care contacts provide opportunities but require provider training and reminder systems. For older adults, mobility limitations and polypharmacy concerns may create unique barriers.

The modelling studies included in this review further underscore the population-level importance of addressing these barriers. Edmunds and colleagues (2000) demonstrated that rubella vaccination strategies targeting only children without catch-up for older age groups could paradoxically increase congenital rubella syndrome incidence. Smith and colleagues (2019) showed that improving HPV vaccine uptake generates substantial long-term health and economic benefits toward cervical cancer elimination. Tokars and colleagues (2018) highlighted the public health impact of maintaining high influenza coverage. Haas and colleagues (2021) provided real-world evidence that high COVID-19 vaccine coverage reduces infections, hospitalisations, and deaths. These studies collectively argue that investment in overcoming vaccination barriers across the life course yields substantial returns.

Limitations of the Evidence Base

Despite the wealth of evidence synthesised in this review, several limitations must be acknowledged. First, the majority of included studies are observational or quasi-experimental, with relatively few randomised controlled trials, particularly for structural and economic interventions. This limits causal inference, although the consistency of findings across diverse settings strengthens confidence in observed associations. Second, there is substantial geographic heterogeneity in the evidence base. While studies from high-income countries (Canada, Europe, Australia) are well-represented, and several LMICs (Ethiopia, Zambia, Bangladesh, Brazil, Madagascar) are included, other regions such as South Asia, the Middle East, and much of sub-Saharan Africa remain understudied. Third, many studies rely on self-reported vaccination status or administrative data with known completeness issues, particularly for migrant and homeless populations who may be poorly captured in routine registries.

Fourth, the definition and measurement of key constructs—vaccine hesitancy, structural barriers, economic constraints—vary considerably across studies, complicating meta-analysis and cross-study comparison. Fifth, few studies explicitly examine intersectional effects, such as how economic and structural barriers compound for specific subgroups (e.g., low-income migrant women). Sixth, the time frame of included studies spans from 2000 to 2026, and changes in vaccination policy, technology, and public attitudes over this period may limit comparability. Seventh, publication bias may favour studies reporting significant associations or positive intervention effects, potentially overestimating the strength of determinants and effectiveness of interventions.

Finally, this review did not quantitatively pool effect sizes due to heterogeneity in outcomes, populations, and intervention types. While the thematic synthesis provides a comprehensive narrative, future meta-analyses focused on specific vaccines (e.g., HPV, influenza) or specific populations (e.g., migrants, pregnant women) would complement this work.

Future Research Directions

Building on the findings of this synthesis, several priorities for future research emerge. First, there is an urgent need for randomised controlled trials of structural and economic interventions, particularly those targeting migrant, homeless, and Indigenous populations. Quasi-experimental designs using natural policy experiments (e.g., changes in pharmacist immunisation scope, school-based consent processes) could provide high-quality evidence where randomisation is infeasible. Second, standardised measurement tools for behavioural, structural, and economic determinants should be developed and validated across diverse cultural and linguistic contexts to enable cross-study comparison and meta-analysis.

Third, implementation science research is needed to understand not just whether interventions work, but how they can be scaled and sustained. The adaptive approach described by Pavon cello and colleagues (2025) and the community-oriented primary care model described by Sangwe and colleagues (2024) warrant further evaluation in additional settings. Fourth, research should explicitly examine intersectionality, using methods such as qualitative comparative analysis or multilevel modelling with interaction terms, to identify how multiple disadvantages compound to create extreme under vaccination.

Fifth, cost-effectiveness studies of interventions addressing behavioural, structural, and economic barriers are needed to guide resource allocation decisions, particularly in LMICs where budgets are most constrained. Sixth, digital interventions require further evaluation, including assessment of their effectiveness across different age groups, literacy levels, and access to technology. Seventh, longitudinal studies tracking vaccination status across the life course, with linkage to administrative data on healthcare use, socioeconomic status, and geographic mobility, would elucidate critical transition points where interventions could be targeted.

Policy and Practice Implications

Several clear implications for policy and practice emerge from this synthesis. First, vaccination programmes must adopt multi-component strategies that address behavioural, structural, and economic barriers simultaneously. Single-component interventions—education alone, cost reduction alone, or reminder systems alone—are unlikely to close coverage gaps in populations facing multiple, intersecting barriers. Second, structural barriers require structural solutions: expanding vaccination sites (including pharmacies, workplaces, schools, and mobile units), streamlining consent processes, integrating vaccination into routine care for marginalised populations, and investing in data systems that track vaccination across the life course and across providers.

Third, behavioural barriers require communication strategies that are tailored to specific populations, addressing their unique concerns (e.g., sexual disinhibition beliefs for HPV, religious beliefs for COVID-19, low perceived risk for influenza). Provider announcement training should be scaled, as the evidence suggests it is more effective than conversation-based approaches for initial vaccine recommendations. Fourth, economic barriers require removal of both direct and indirect costs, including transportation reimbursement, flexible clinic hours to accommodate work schedules, and paid time off for vaccination.

Fifth, school-based programs should be strengthened through automated consent processes, reminder systems, and dedicated clinic time, with particular attention to reaching students from low-income, migrant, and language-minority families. Sixth, national immunisation strategies must explicitly include migrant, homeless, and Indigenous populations, with dedicated outreach, culturally appropriate services, and data systems that enable monitoring of coverage in these groups.

Strengths and Limitations of This Review

This systematic synthesis has several strengths. It includes 46 studies published over a 26-year period (2000–2026), providing a comprehensive overview of the evidence base. Studies span high-, middle-, and low-income countries and cover multiple vaccine types (HPV, influenza, COVID-19, measles, rubella, cholera, dengue, pneumococcal, varicella, mpox). The thematic synthesis organised findings into behavioural, structural, and economic domains, which align with established frameworks for understanding vaccination determinants. The inclusion of both observational studies and intervention trials enables identification of both associations and causal effects.

Limitations of this review include the lack of quantitative meta-analysis, reliance on published English-language literature (potentially missing studies in other languages), and the absence of formal quality assessment scoring for each included study. However, given the heterogeneity of study designs and outcomes, a narrative synthesis was the most appropriate approach. Future updates of this review could incorporate formal quality assessment and, where feasible, meta-analysis for specific vaccine-population combinations.

CONCLUSION

This systematic synthesis of 46 studies demonstrates that vaccination uptake among adolescents and adults is shaped by a complex interplay of behavioural, structural, and economic determinants. Vaccine hesitancy—driven by low perceived risk, safety concerns, religious beliefs, and inadequate knowledge—remains a pervasive behavioural barrier. Structural barriers including geographic disparities, exclusion of migrant and homeless populations, fragmented school-based delivery systems, and limited provider access consistently undermine equitable coverage. Economic constraints disproportionately affect vulnerable populations, even in universal healthcare settings. Multi-component interventions addressing multiple determinant categories simultaneously—including new media reminders, provider communication training, school-based process improvements, community-engaged outreach, and removal of financial barriers—show the greatest effectiveness. Achieving high and equitable vaccination coverage across the life course requires integrated strategies that address behavioural, structural, and economic barriers in parallel, with sustained investment in implementation research, policy reform, and service delivery innovation. The COVID-19 pandemic has underscored the urgency of this task, as gaps in routine vaccination leave populations vulnerable to both emerging and vaccine-preventable diseases. A life-course immunisation approach, underpinned by equity-focused policies and programmes, is essential to realise the full public health potential of vaccination.

Recommendations

For Policymakers

• Develop integrated immunization policies that address behavioural, structural, and economic barriers simultaneously.
• Ensure free or subsidized vaccination services for adolescents and adults, especially for HPV, influenza, and booster vaccines.
• Expand vaccination access through mobile clinics, workplace programmes, schools, pharmacies, and community-based delivery systems.
• Strengthen national immunization information systems to improve vaccine tracking and coverage monitoring.
• Provide culturally and linguistically appropriate vaccination services for vulnerable and marginalized populations.

For Healthcare Providers

• Use clear, confident, and evidence-based communication while recommending vaccines.
• Address vaccine hesitancy through respectful counselling and accurate information on vaccine safety and effectiveness.
• Implement reminder systems and standing vaccination orders in healthcare facilities.
• Encourage vaccination during every healthcare interaction, including routine and emergency visits.
• Collaborate with community leaders and local organizations to improve trust and awareness.

For Public Health Practitioners

• Conduct targeted awareness campaigns to counter misinformation and improve vaccine confidence.
• Use community outreach programmes to reach underserved populations in rural and low-resource settings.
• Monitor vaccination coverage using disaggregated data to identify gaps among high-risk groups.
• Integrate vaccination services with other health and social welfare programmes for better accessibility.
• Promote community participation in the planning and implementation of immunization campaigns.

For Researchers

• Conduct longitudinal and implementation-based studies to understand long-term vaccination behaviours and barriers.
• Evaluate the effectiveness of digital interventions, reminder systems, and community-based approaches.
• Generate evidence on cost-effective strategies to improve vaccine uptake among adolescents and adults.

Explore the interaction between behavioural, structural, and economic determinants across diverse populations.

REFERENCES

1. WHO Results Report 2020-2021 [Internet]. [cited 2026 May 22]. Available from: https://www.who.int/about/accountability/results/who-results-report-2020-2021
2. The State of the World’s Children 2023 | UNICEF [Internet]. [cited 2026 May 21]. Available from: https://www.unicef.org/reports/state-worlds-children-2023
3. European Centre for Disease Prevention and Control. Seasonal influenza vaccination recommendations and coverage rates in EU/EEA Member States: an overview of vaccination recommendations for 2021−22 and coverage rates for the 2018–19 to 2020–21 influenza seasons. [Internet]. LU: Publications Office; 2023 [cited 2026 May 21]. Available from: https://data.europa.eu/doi/10.2900/335933 doi:10.2900/335933
4. MacDonald NE, SAGE Working Group on Vaccine Hesitancy. Vaccine hesitancy: Definition, scope and determinants. Vaccine. 2015 Aug 14;33(34):4161–4. doi:10.1016/j.vaccine.2015.04.036 PubMed PMID: 25896383.
5. Larson HJ, Jarrett C, Eckersberger E, Smith DMD, Paterson P. Understanding vaccine hesitancy around vaccines and vaccination from a global perspective: a systematic review of published literature, 2007-2012. Vaccine. 2014 Apr 17;32(19):2150–9. doi:10.1016/j.vaccine.2014.01.081 PubMed PMID: 24598724.
6. Dubé E, Laberge C, Guay M, Bramadat P, Roy R, Bettinger JA. Vaccine hesitancy. Hum Vaccines Immunother. 2013 Aug 1;9(8):1763–73. doi:10.4161/hv.24657 PubMed PMID: 23584253; PubMed Central PMCID: PMC3906279.
7. Using Behavioral Insights to Increase Vaccination Policy Effectiveness - Cornelia Betsch, Robert Böhm, Gretchen B. Chapman, 2015 [Internet]. [cited 2026 May 21]. Available from: https://journals.sagepub.com/doi/abs/10.1177/2372732215600716
8. WDR 2022 Chapter 1. Introduction [Internet]. [cited 2026 May 21]. Available from: https://www.worldbank.org/en/publication/wdr2022/brief/chapter-1-introduction-the-economic-impacts-of-the-covid-19-crisis
9. Brewer NT, Chapman GB, Rothman AJ, Leask J, Kempe A. Increasing Vaccination: Putting Psychological Science Into Action. Psychol Sci Public Interest J Am Psychol Soc. 2017 Dec;18(3):149–207. doi:10.1177/1529100618760521 PubMed PMID: 29611455.
10. Schmid P, Rauber D, Betsch C, Lidolt G, Denker ML. Barriers of Influenza Vaccination Intention and Behavior - A Systematic Review of Influenza Vaccine Hesitancy, 2005 - 2016. PloS One. 2017;12(1):e0170550. doi:10.1371/journal.pone.0170550 PubMed PMID: 28125629; PubMed Central PMCID: PMC5268454.
11. Chuma DM, Machacha R, Adjagba AO, January J. Behavioural and Social Drivers (BeSD) of HPV vaccination in Zimbabwe: A Rapid Scoping Review of Literature. Asian Pac J Cancer Prev APJCP. 2025 Mar 1;26(3):775–83. doi:10.31557/APJCP.2025.26.3.775 PubMed PMID: 40156393; PubMed Central PMCID: PMC12174526.
12. Ejnar Hansen M, David Pickering S. The role of religion and COVID-19 vaccine uptake in England. Vaccine. 2024 May 10;42(13):3215–9. doi:10.1016/j.vaccine.2024.04.006 PubMed PMID: 38677793.
13. Akmatova R, Dzhangaziev B, Ebama MS, Otorbaeva D. Knowledge, attitudes, and practices (KAP) towards seasonal influenza and influenza vaccine among pregnant women in Kyrgyzstan: A cross-sectional study. Vaccine. 2024 Oct 24;42 Suppl 4:125510. doi:10.1016/j.vaccine.2023.12.020 PubMed PMID: 38072755.
14. Mayer MK, Reiter PL, Zucker RA, Brewer NT. Parents’ and Sons’ Beliefs in Sexual Disinhibition After Human Papillomavirus Vaccination. Sex Transm Dis. 2013 Oct;40(10):822–8. doi:10.1097/OLQ.0000000000000021 PubMed PMID: 24275737; PubMed Central PMCID: PMC4227592.
15. Atkinson K, Ntacyabukura B, Hawken S, El-Khatib Z, Laflamme L, Wilson K. Parent and family characteristics associated with reported pediatric influenza vaccination in a sample of Canadian digital vaccination platform users. An exploratory, cross-sectional study in the 2018-2019 influenza season. Hum Vaccines Immunother. 2024 Dec 31;20(1):2378580. doi:10.1080/21645515.2024.2378580 PubMed PMID: 39034882; PubMed Central PMCID: PMC11789738.
16. Farmanara N, Sherrard L, Dubé È, Gilbert NL. Determinants of non-vaccination against seasonal influenza in Canadian adults: findings from the 2015–2016 Influenza Immunization Coverage Survey. Can J Public Health Rev Can Santé Publique. 2018 Mar 30;109(3):369–78. doi:10.17269/s41997-018-0018-9 PubMed PMID: 29981075; PubMed Central PMCID: PMC6153712.
17. Gabellone V, Nuccetelli F, Fortunato F, Ascatigno L, Prato R, Lopalco PL. Opinions and attitudes toward influenza vaccination among male Italian volleyball Serie A athletes in the 2024/25 season. J Sci Med Sport. 2026 May;29(5):454–8. doi:10.1016/j.jsams.2025.11.002 PubMed PMID: 41271464.
18. Dubé E, Gagnon D, Pelletier C, Comeau JL, Steenbeek A, MacDonald N, et al. Enhancing HPV vaccine uptake in girls and boys - A qualitative analysis of Canadian school-based vaccination programs. Vaccine. 2024 Dec 2;42(26):126425. doi:10.1016/j.vaccine.2024.126425 PubMed PMID: 39423449.
19. Dionne M, Étienne D, Witteman HO, Sauvageau C, Dubé È. Impact of interventions to improve HPV vaccination acceptance and uptake in school-based programs: Findings of a pilot project in Quebec. Vaccine. 2024 Jul 11;42(18):3768–73. doi:10.1016/j.vaccine.2024.04.089 PubMed PMID: 38714451.
20. Skinner SR, Davies C, Cooper S, Stoney T, Marshall H, Jones J, et al. HPV.edu study protocol: a cluster randomised controlled evaluation of education, decisional support and logistical strategies in school-based human papillomavirus (HPV) vaccination of adolescents. BMC Public Health. 2015 Sep 15;15:896. doi:10.1186/s12889-015-2168-5 PubMed PMID: 26373926; PubMed Central PMCID: PMC4572679.
21. Baroutsou V, Wymann M, Zens K, Sinniger P, Fehr J, Lang P. National and regional variations in timely adherence to recommended measles vaccination scheme in 2-years old in Switzerland, 2005-2019. Vaccine. 2022 May 11;40(22):3055–63. doi:10.1016/j.vaccine.2022.04.008 PubMed PMID: 35437190.
22. Preto C, Maron de Mello A, Cesário Pereira Maluf EM, Teixeira Krainski E, Graeff G, de Sousa GA, et al. Vaccination coverage and adherence to a dengue vaccination program in the state of Paraná, Brazil. Vaccine. 2021 Jan 22;39(4):711–9. doi:10.1016/j.vaccine.2020.12.030 PubMed PMID: 33386178.
23. Giambi C, Del Manso M, Dalla Zuanna T, Riccardo F, Bella A, Caporali MG, et al. National immunization strategies targeting migrants in six European countries. Vaccine. 2019 Jul 26;37(32):4610–7. doi:10.1016/j.vaccine.2018.01.060 PubMed PMID: 29426661.
24. Faijue DD, Bouaddi O, Mackey K, Deal A, Cinar EN, Morais B, et al. Strategies, interventions, and uptake of catch-up vaccination among adolescent and adult migrants, refugees, and internally displaced persons (IDPs) in low- and middle-income countries (LMICs): A systematic review. Vaccine. 2026 Mar 7;75:128249. doi:10.1016/j.vaccine.2026.128249 PubMed PMID: 41564840.
25. Eurich DT, Weaver O, McDermott C, Soprovich A, Wozniak LA, Woytas B, et al. Describing COVID-19 immunizations for First Nations people on-reserve in Alberta using real-time integration of point of care and provincial data. Vaccine. 2025 Jan 25;45:126614. doi:10.1016/j.vaccine.2024.126614 PubMed PMID: 39700910.
26. Sangwe CN, Budzi MN, Shifu IN, Ghangha JG, Njedock SN. The use of community-oriented primary care (COPC) model to generate vaccine demand: The case of a remote fishing community in Cameroon. Vaccine. 2024 Nov 14;42 Suppl 5:126173. doi:10.1016/j.vaccine.2024.126173 PubMed PMID: 39089959.
27. R. Mugali R, Ip H, Zikusooka A, Vong L, Bou S, Kros S, et al. Striving for equitable vaccination coverage: Leveraging rapid coverage and community assessments during the COVID-19 pandemic to reach missed populations in Cambodia. Vaccine. 2024 Nov 14;VARN2023: When Communities Lead, Global Immunization Succeeds42:126016. doi:10.1016/j.vaccine.2024.05.064
28. Isenor JE, O’Reilly BA, Bowles SK. Evaluation of the impact of immunization policies, including the addition of pharmacists as immunizers, on influenza vaccination coverage in Nova Scotia, Canada: 2006 to 2016. BMC Public Health. 2018 Jun 26;18(1):787. doi:10.1186/s12889-018-5697-x PubMed PMID: 29940903; PubMed Central PMCID: PMC6019522.
29. Saha A, Hayen A, Ali M, Rosewell A, MacIntyre CR, Clemens JD, et al. Socioeconomic drivers of vaccine uptake: An analysis of the data of a geographically defined cluster randomized cholera vaccine trial in Bangladesh. Vaccine. 2018 Jul 25;36(31):4742–9. doi:10.1016/j.vaccine.2018.04.084 PubMed PMID: 29752024; PubMed Central PMCID: PMC6046469.
30. Dhalaria P, Kumar P, Verma A, Priyadarshini P, Singh AK, Tripathi B, et al. Does unintended birth lead to zero dose of DPT vaccine among children aged 12-23 months in India? Hum Vaccines Immunother. 2024 Dec 31;20(1):2417526. doi:10.1080/21645515.2024.2417526 PubMed PMID: 39506883; PubMed Central PMCID: PMC11542598.
31. Quach S, Hamid JS, Pereira JA, Heidebrecht CL, Deeks SL, Crowcroft NS, et al. Influenza vaccination coverage across ethnic groups in Canada. CMAJ Can Med Assoc J. 2012 Oct 16;184(15):1673–81. doi:10.1503/cmaj.111628 PubMed PMID: 22966054; PubMed Central PMCID: PMC3478352.
32. Kroneman MW, van Essen GA. Variations in influenza vaccination coverage among the high-risk population in Sweden in 2003/4 and 2004/5: a population survey. BMC Public Health. 2007 Jun 14;7:113. doi:10.1186/1471-2458-7-113 PubMed PMID: 17570837; PubMed Central PMCID: PMC1906854.
33. Ladner J, Besson MH, Rodrigues M, Audureau E, Saba J. Performance of 21 HPV vaccination programs implemented in low and middle-income countries, 2009-2013. BMC Public Health. 2014 Jun 30;14:670. doi:10.1186/1471-2458-14-670 PubMed PMID: 24981818; PubMed Central PMCID: PMC4085395.
34. Schaetti C, Ali SM, Chaignat CL, Khatib AM, Hutubessy R, Weiss MG. Improving Community Coverage of Oral Cholera Mass Vaccination Campaigns: Lessons Learned in Zanzibar. PLoS ONE. 2012 Jul 23;7(7):e41527. doi:10.1371/journal.pone.0041527 PubMed PMID: 22844489; PubMed Central PMCID: PMC3402403.
35. Odone A, Ferrari A, Spagnoli F, Visciarelli S, Shefer A, Pasquarella C, et al. Effectiveness of interventions that apply new media to improve vaccine uptake and vaccine coverage. Hum Vaccines Immunother. 2015;11(1):72–82. doi:10.4161/hv.34313 PubMed PMID: 25483518; PubMed Central PMCID: PMC4514191.
36. Zoni AC, Esteban-Vasallo MD, Domínguez-Berjón MF, Sendra JM, Astray-Mochales J. Coverage and predictors of influenza vaccination in patients with cystic fibrosis in a campaign with a mobile phone text messaging intervention. Hum Vaccines Immunother. 2019;15(1):102–6. doi:10.1080/21645515.2018.1520585 PubMed PMID: 30192711; PubMed Central PMCID: PMC6363150.
37. Gilano G, Dekker A, Fijten R. The effect of mHealth on childhood vaccination and its associated factors among South Ethiopian mothers: a cluster randomized controlled trial. Sci Rep. 2025 Nov 24;15(1):41668. doi:10.1038/s41598-025-25568-2 PubMed PMID: 41286074; PubMed Central PMCID: PMC12644492.
38. Ou L, Youngstedt SD. The Role of Vaccination Interventions to Promote HPV Vaccine Uptake Rates in a College-Aged Population: a Systematic Review. J Cancer Educ Off J Am Assoc Cancer Educ. 2022 Apr;37(2):244–50. doi:10.1007/s13187-020-01806-1 PubMed PMID: 32564253; PubMed Central PMCID: PMC8986718.
39. Malo TL, Hall ME, Brewer NT, Lathren CR, Gilkey MB. Why is announcement training more effective than conversation training for introducing HPV vaccination? A theory-based investigation. Implement Sci IS. 2018 Apr 19;13(1):57. doi:10.1186/s13012-018-0743-8 PubMed PMID: 29673374; PubMed Central PMCID: PMC5907716.
40. Cartmell KB, Young-Pierce J, McGue S, Alberg AJ, Luque JS, Zubizarreta M, et al. Barriers, facilitators, and potential strategies for increasing HPV vaccination: A statewide assessment to inform action. Papillomavirus Res. 2018 Jun;5:21–31. doi:10.1016/j.pvr.2017.11.003 PubMed PMID: 29248818; PubMed Central PMCID: PMC5886972.
41. Wong VWY, Lok KYW, Tarrant M. Interventions to increase the uptake of seasonal influenza vaccination among pregnant women: A systematic review. Vaccine. 2016 Jan 2;34(1):20–32. doi:10.1016/j.vaccine.2015.11.020 PubMed PMID: 26602267.
42. Braeckman T, Theeten H, Roelants M, Blaizot S, Hoppenbrouwers K, Maertens K, et al. Can Flanders resist the measles outbreak? Assessing vaccination coverage in different age groups among Flemish residents. Epidemiol Infect. 2018 Jun;146(8):1043–7. doi:10.1017/S0950268818000985 PubMed PMID: 29716667; PubMed Central PMCID: PMC9184938.
43. Edmunds WJ, van de Heijden OG, Eerola M, Gay NJ. Modelling rubella in Europe. Epidemiol Infect. 2000 Dec;125(3):617–34. doi:10.1017/s0950268800004660 PubMed PMID: 11218213; PubMed Central PMCID: PMC2869646.
44. Smith A, Baines N, Memon S, Fitzgerald N, Chadder J, Politis C, et al. Moving toward the elimination of cervical cancer: modelling the health and economic benefits of increasing uptake of human papillomavirus vaccines. Curr Oncol. 2019 Apr;26(2):80–4. doi:10.3747/co.26.4795 PubMed PMID: 31043805; PubMed Central PMCID: PMC6476443.
45. Tokars JI, Rolfes MA, Foppa IM, Reed C. An evaluation and update of methods for estimating the number of influenza cases averted by vaccination in the United States. Vaccine. 2018 Nov 19;36(48):7331–7. doi:10.1016/j.vaccine.2018.10.026 PubMed PMID: 30327213; PubMed Central PMCID: PMC6666399.
46. Khatuja N, Aggarwal R, Dutta T, Mahajan M. Safety profile of India’s influenza vaccine in a large-scale corporate vaccination drive. Hum Vaccines Immunother. 2026 Dec;22(1):2622188. doi:10.1080/21645515.2026.2622188 PubMed PMID: 41631848; PubMed Central PMCID: PMC12885390.