Open research questions in Vaccine Coverage and Hesitancy

What the literature leaves open

• 6 Strengths and Limitations This study benefits from a reasonably large sample of 500 caregivers recruited across six primary healthcare centers spanning both sides of Mosul City and from a structured three conceptually distinct domains, allowing their relative contributions to be compared directly.

  BARRIERS FOR ROUTINE IMMUNIZATIONS AMONG UNDER SIX YEARS CHILDREN IN MOSUL CITY · 2026 · DOI

• The before-after comparison is limited by the use of two different time periods, during which factors other than the implementation of a preschool booster may also have influenced pertussis epidemiology. No effectiveness studies have been conducted with the Finnish wP vaccines and estimates from previ- ous studies on effectiveness of other wP vaccines vary widely.

  Effectiveness and impact of the 2-component acellular pertussis vaccine as a preschool booster in Finland – A register-based study · 2026 · DOI

• However, after hospital discharge, these medically vulnerable children may remain insufficiently protected against vaccine-preventable infections because of prolonged temporary medical exemptions, clinical caution, parental concerns, and fragmented coordination between specialized follow-up services and primary health care.

  Immunization Gaps Among High-Risk Preterm Infants in Kazakhstan · 2026 · DOI

• Background: Children with congenital heart disease (CHD) are highly vulnerable to influenza, yet real-world vaccine effectiveness (VE) data in this post-operative population are lacking, especially in China.

  Influenza Vaccine Effectiveness Against Influenza-like Illness in Post-Operative Children with Congenital Heart Disease: A Retrospective Cohort Study Using Inverse Probability of Treatment Weighting · 2026 · DOI

• Frontiers in Epidemiology 12 frontiersin.org Galindo-Fraga et al. 10.3389/fepid.2026.1826780 avoidable morbidity and mortality. This becomes even more relevant considering the substantial socioeconomic burden associated with influenza-related disease (18, 19). affecting limitations Low vaccination coverage among populations at risk is likely multifactorial. Contributing factors may include vaccine hesitancy, missed vaccination opportunities during healthcare encounters, limited awareness regarding vaccination recommendations, and programmatic or operational vaccine accessibility, availability, and timely distribution within public healthcare systems (21, 22). Previous studies have shown that healthcare access barriers, regarding vaccination, and operational challenges within immunization programs may substantially influence vaccination uptake among (21, 22). Although Mexican public vulnerable populations healthcare implemented strategies aimed at expanding influenza vaccination among populations at risk, our findings suggest that a considerable proportion of eligible individuals remain unvaccinated. Operational challenges associated with identifying specific vaccination-eligible conditions, such as morbid obesity, may also contribute to underrecognition of eligible individuals within routine vaccination practices. insufficient knowledge institutions have is needed to better characterize An additional finding of interest was the large proportion of vaccine doses classified within undefined “other groups.”

  Estimation of populations at risk for severe influenza and vaccination coverage in Mexico, 2010–2021 · 2026 · DOI

• Future research should explore acceptability of 4CMenB vaccination among other populations, such as sex-workers. There is also a need to examine how structural inequalities, such as socioeconomic deprivation and ethnicity, shape vaccine access and uptake. Quantitative evaluation of early implementation phases could help identify inequities in vaccine offer and uptake, informing more inclusive delivery strategies, while also providing early real-world evidence on vaccine effectiveness.

  Understanding the acceptability, barriers and facilitators to implementing the 4CMenB vaccine for the prevention of gonorrhoea in gay, bisexual and other men who have sex with men · 2026 · DOI

• Strengths and limitations of this study This study acknowledges some limitations, including reliance on a small, self-selecting sample, which limits the transferability of the findings beyond the specific communities represented. A key limitation of this study is that participants were recruited from a single state in Nigeria and predominantly comprised individuals with higher levels of education.

  Reframing vaccine narrative: a co-production study of a media campaign intervention to address childhood vaccine hesitancy among Nigerian parents and caregivers · 2026 · DOI

• healthcare workers have been defined by organisations such as the Centers for Disease for Kenger NM, et al. Control and Prevention, and include vaccines such as those for influenza, MMR, hepatitis B, Tdap and chickenpox. Furthermore, Regulation 15/06/2013 on the prevention of exposure risks that to biological agents explicitly states employers in our country must provide appropriate vaccinations for their employees. However, the low vaccination rates identified in the current study suggest that there may be a discrepancy between legislation and practice. Examining the reasons nurses gave for not getting vaccinated revealed that the most frequently reported reasons were possible complications of the vaccine (39.2%), distrust of vaccines (37.6%), and lack of information (32.4%). These findings are consistent with the concept of 'vaccine hesitancy', as defined in the literature. Studies by Galanakis et al. (2013) and Khubchandani et al. (2022) have also reported that concerns and misconceptions about vaccine safety among healthcare workers have a negative effect on vaccination rates (21-22). As healthcare workers are role models for the community, this hesitancy may have individual and societal consequences.

  Examining The Knowledge Levels And Attitudes Towards Vaccinations Of Nurses Working At University Hospitals Regarding Biological Risks And Vaccinations · 2026 · DOI

• Abstract Objectives The evidence on coronavirus disease 2019 (COVID-19) vaccine uptake in Central and Eastern Europe remains sparse.

  Predictors of COVID-19 vaccination status: a nationwide linkage study in Czechia · 2026 · DOI

• Nurses are encouraged to continuously improve their communication skills and participate in training focused on vaccine education and patient interaction. Healthcare institutions should provide adequate staffing, training, and educational materials. Policy makers should strengthen immunization policies and address misinformation, especially on digital platforms, to improve public trust in vaccines. Future researchers are advised to explore parental perspectives further to gain a deeper understanding of vaccine hesitancy factors. Community and public health programs should enhance collaboration with healthcare workers and local leaders to promote vaccine awareness and address cultural influences.

  Nurses as Vaccine Advocates: Effective Strategies for Overcoming Vaccine Hesitancy In the Pediatric Population · 2026 · DOI

• Future research should explore optimal strategies for integrating personalized AI interactions alongside structural interventions, ultimately aiming for a multifaceted approach to address deep-rooted vaccine hesitancy effectively.

  Large Language Model Chatbot Conversations vs Public Health Materials and Parental HPV Vaccination Intentions · 2026 · DOI

• This study has strengths. It provides rich, context-specific qualitative data from a previously unstudied community in Rivers State. The sample includes multiple perspectives. Data saturation was achieved. However, limitations exist. The findings are not statistically generalizable. Data were collected through handwritten notes rather than audio recording due to participant refusal. Recruitment through health facilities may have excluded caregivers completely disconnected from the health system.

  Lived Experiences and Socio-Cultural Influences of Vaccine Hesitancy in Oyigbo, Rivers State, Nigeria · 2026 · DOI

• This study has limitations. Findings are not statistically generalizable. Handwritten notes were used instead of audio recording due to participant refusal. Future research should include quantitative surveys and intervention studies in other LGAs to test engaging religious leaders and flexible clinic hours.

  Lived Experiences and Socio-Cultural Influences of Vaccine Hesitancy in Oyigbo, Rivers State, Nigeria · 2026 · DOI

• Strengths First, our design leverages public, regularly updated global datasets with clear provenance, enhancing transparency and reproducibility. Coverage metrics are drawn from the WHO– UNICEF Estimates of National Immunization Coverage, which are updated annually; we follow the documented reporting cycle and flag any carried-forward values in figures and text (5). Second, we pair service metrics with decision-relevant context signals rather than generic covariates, including an affordability indicator and crisis vulnerability using the INFORM risk framework (48). Third, we put equity at the center by stratifying recovery against refugee burden and system risk; this approach aligns the analysis with populations most likely to be missed and links directly to delivery playbooks and financing levers. Finally, we align with transparency norms of Frontiers: all sources are citable, publicly accessible and will be documented in a Data Availability Statement with access dates and URLs, consistent with the policy of Frontiers. 5.2 Limitations This is an ecological, multicountry analysis; the results quantify system-level associations and should not be interpreted as causal estimates at the individual level. Measurement error is inherent: coverage estimates rely on reporting and review processes, and measles surveillance may be affected by underascertainment or reporting lags, which can bias annual counts (10). We mitigate these limitations by using widely adopted series and by flagging instances where 2024 values are carried forward from 2023, although some residual bias may persist. Macroaffordability is measured only for a subset of countries covered by the World Bank inflation dataset; we aggregate monthly signals to annual means or max-month values, which may attenuate short-lived shocks. The INFORM Risk index is composite by design; while it captures multidimensional vulnerability, any index compresses heterogeneity and can mask (48). Our visuals are locally address descriptive; overdispersion and clustering, unobserved confounding may still be present. National aggregates may mask subnational heterogeneity in both coverage and measles dynamics; future subnational denominators and work mobility-aware microplanning data. Finally, tail behavior is informed by smaller samples at extreme levels of inflation or risk; we report wide uncertainty bands and interpret these patterns as directional signals rather than precise effect estimates. Additional limitations include residual confounding, withincountry heterogeneity not captured by national indicators, and variation in measles surveillance sensitivity across settings (10).

  Operational intelligence for immunization recovery: mapping system shocks and capacity to zero-dose debt and outbreak risk · 2026 · DOI

• Nurses' limited knowledge and skills in engaging students with IDD can result in unethical practices, students feeling excluded from vaccination decisions, and students being traumatized by negative treatment experiences.

  Vaccinating Adolescents With Intellectual and Developmental Disability at School: An Opportunity to Promote Supported Decision Making · 2025 · DOI

• Given these complexities, should teachers promote vaccination? If so, should this extend beyond scientifically evidenced propositions to include the moral and civic virtues of immunization? Drawing on recent philosophical work on teaching controversial issues, Ruth Wareham argues that teachers are warranted in promoting both the scientific case for vaccine safety and efficacy and the moral case for vaccination qua civic duty.

  Should Teachers Promote Vaccination? · 2025 · DOI

• It remains unclear though if Americans with differing racial/ethnic identities and religious affiliations are equally likely to receive health-related information in religious settings and endorse COVID-19 vaccination.

  Religious and Racial/Ethnic Differences in Flu and COVID-19 Vaccination Intentions · 2023 · DOI

• RESULTS: This study afforded three themes of COVID-19 vaccine hesitancy: (a) fear and mistrust (subthemes: influence of Dengvaxia vaccine, the influence of people who refuse to be vaccinated, lack of trust in the government, lack of trust in healthcare workers, doubts on vaccines' effectiveness), (b) misinformation and disinformation (subthemes: misbeliefs, insufficient knowledge), and (c) adamant attitudes (subthemes: unwillingness to be vaccinated, picky on vaccine brand).

  Filipinos’ COVID‐19 vaccine hesitancy comments in TikTok videos: A manifest content analysis · 2022 · DOI

• Our empirical evidence sheds light on an understudied phenomenon-parents switching from one doctor to another provider (often one offering CAM services) around issues that arise during vaccination consultations.

  Trust, affect, and choice in parents’ vaccination decision‐making and health‐care provider selection in Switzerland · 2021 · DOI

• Adults who are at high-risk of COVID-19 may overwhelmingly choose to receive a vaccine, but it remains unclear if an exclusively adult targeted vaccine campaign would be sufficient to interrupt transmission.

  Vaccine hesitancy in low- and middle-income countries: potential implications for the COVID-19 response · 2020 · DOI

• Although the WHO recently concluded that current evidence does not justify changes to immunisation policy, further studies of sufficient size and quality are needed to assess the importance of NSE for all-cause mortality.

  Non-specific effects of vaccines: plausible and potentially important, but implications uncertain · 2017 · DOI

• CONCLUSIONS: Results indicate a need for further research on the role of local culture, including religion and faith, in rural African Americans' decisions about giving their children the HPV vaccination.

  Rural African American Parents’ Knowledge and Decisions About Human Papillomavirus Vaccination · 2012 · DOI

• Adverse reactions associated with BCG vaccination have been well documented, but events due to accidental overdose and/or improper vaccination are scarce in the literature.

  Accidental Overdose and Improper Vaccination with BCG in Childhood: Report of Three Cases · 2011 · DOI

• Although numerous studies on non-governmental organizations (NGOs) suggest that the extent of NGO provision of immunization services in low- and middle-income countries is substantial, the contribution of this sector is poorly documented, leading to a lack of recognition of its role at national and global levels.

  Role of the private sector in the provision of immunization services in low- and middle-income countries · 2011 · DOI

• Additional research into sustainable funding sources and the comprehensive effects of SLIV programs on students, families, staff, and the community is warranted.

  The Impact of School-Located Influenza Vaccination Programs on Student Absenteeism · 2010 · DOI

Most-cited papers in Vaccine Coverage and Hesitancy

• A global database of COVID-19 vaccinations · Nature Human Behaviour · 2021 · 1,485 citations
• Measuring the impact of COVID-19 vaccine misinformation on vaccination intent in the UK and USA · Nature Human Behaviour · 2021 · 1,414 citations
• COVID-19 Vaccination Hesitancy in the United States: A Rapid National Assessment · Journal of Community Health · 2021 · 902 citations
• Conspiracy theories as barriers to controlling the spread of COVID-19 in the U.S. · Social Science & Medicine · 2020 · 861 citations
• Effects of the COVID-19 Pandemic on Routine Pediatric Vaccine Ordering and Administration — United States, 2020 · MMWR Morbidity and Mortality Weekly Report · 2020 · 567 citations
• Influenza vaccine uptake, COVID-19 vaccination intention and vaccine hesitancy among nurses: A survey · International Journal of Nursing Studies · 2020 · 550 citations
• COVID-19 vaccine hesitancy in the UK: the Oxford coronavirus explanations, attitudes, and narratives survey (Oceans) II · Psychological Medicine · 2020 · 539 citations
• Contribution of vaccination to improved survival and health: modelling 50 years of the Expanded Programme on Immunization · The Lancet · 2024 · 519 citations
• The Nature and Extent of COVID-19 Vaccination Hesitancy in Healthcare Workers · Journal of Community Health · 2021 · 466 citations
• Fearing the disease or the vaccine: The case of COVID-19 · Personality and Individual Differences · 2020 · 396 citations

Most recent work

• Operational intelligence for immunization recovery: mapping system shocks and capacity to zero-dose debt and outbreak risk · Frontiers in Health Services · 2026
• “Solidarity is No One-Way Street” – The Effects of COVID-19 Framings on Attitudes Towards Cost-Sharing for Inpatient Treatment in Germany · Statistics Politics and Policy · 2026
• Jabs or societal restrictions? Public preferences for vaccination programmes in South Africa · Health Policy and Technology · 2026
• Six ways Gavi will continue to immunise half the world's children amid vaccine backlash and a funding crisis · BMJ · 2026
• How proximity and trust of policy narrators motivate their audience · Journal of Public Policy · 2026
• Is a Planned Newborn Hepatitis B Vaccine Trial in Guinea‐Bissau Unethical? · Developing World Bioethics · 2026
• The Importance of the Childhood Immunization Schedule for Internal Medicine · Annals of Internal Medicine · 2026
• Parents ' Attitudes Toward Childhood Vaccinations: A descriptive study · Journal of Contemporary Medicine · 2026
• Designing for Adolescent Voice in Health Decisions: Embodied Conversational Agents for HPV Vaccination · 2026
• My child is one in a million: Parents hesitant to vaccinate their children, or communities of practice in the field of (alternative) medicine · Current Sociology · 2026

Related topics in Social Sciences