Vaccine hesitancy is significantly impacting global childhood vaccination rates

The question is whether vaccine hesitancy materially contributes to reduced or delayed childhood vaccination worldwide, while distinguishing that contribution from failures of access, supply, and health-system delivery. The practical stakes concern both the interpretation of stalled coverage and the choice between demand-focused, delivery-focused, or combined responses. The strongest support for the claim is consistent evidence that vaccine hesitancy is associated with non-vaccination, delayed doses, and incomplete childhood vaccination schedules. A systematic review and meta-analysis found this relationship across vaccination behaviors, and an observational study found parental hesitancy and vaccine beliefs predicted intention and/or uptake of routine childhood immunizations. A separate worldwide review found parental hesitancy toward routine childhood vaccination to be common across the included studies, although highly heterogeneous across definitions, countries, samples, and survey periods. Population-level reporting and cross-national research identify confidence, misinformation, complacency, and vaccine-hesitant populations as relevant drivers of missed vaccination, alongside other causes. UNICEF reported declining confidence in childhood vaccines in many countries after COVID-19, while a large cross-national modelling study found substantial geographic and temporal variation in confidence and identified it as an important determinant of willingness to vaccinate (see Figure 3). WHO’s behavioral framework treats motivation, including confidence and concerns, as a pathway to vaccination behavior, and WHO/UNICEF coverage reporting includes misinformation and declining confidence among the factors contributing to missed vaccination. The global relevance of these demand-side risks is underscored by the continuing scale of children who are unvaccinated or incompletely vaccinated. WHO and UNICEF reported that global routine childhood immunization coverage stalled in 2023, with approximately 14.5 million infants receiving no vaccines and millions more incompletely vaccinated (see Figure 1). The strongest challenge is that many global coverage gaps arise in settings where vaccination services are inaccessible or disrupted, so non-vaccination cannot generally be attributed mainly to caregiver hesitancy. UNICEF and Gavi report that zero-dose children are disproportionately concentrated in marginalized, poor, remote, conflict-affected, and otherwise underserved communities, a distribution consistent with structural barriers to reaching services. WHO likewise identifies inadequate health services and conflict, as well as misinformation, complacency, and hesitancy, as causes of missed vaccination; its reporting does not quantify the independent share attributable to each factor. The COVID-19 period provides direct evidence that childhood coverage can fall substantially through delivery and access mechanisms independent of a measured change in vaccine acceptance. A global modelling study attributed pandemic-era routine-vaccination disruptions to lockdowns, service interruption, mobility restrictions, and health-system disruption, while a systematic review documented reduced service use and coverage associated with disrupted services, fear of facility attendance, and movement restrictions (see Figure 2). Some pandemic-related fear and trust concerns may overlap conceptually with hesitancy, but the documented system-level mechanisms remain a substantial competing explanation for lower coverage. The evidence supports hesitancy as a meaningful contributor to childhood under-vaccination, but not as a uniformly defined, globally quantified, or dominant cause of coverage gaps. Reviews find inconsistent definitions and measurement of vaccine hesitancy, and studies vary in whether they incorporate confidence, complacency, convenience, or related practical influences. This conceptual overlap matters because adherence is also shaped by provider trust, socioeconomic conditions, service availability, and other individual, social, health-system, and contextual influences. Evidence on interventions reinforces that missed doses can reflect both demand-side and practical barriers, making combined approaches more responsive to the evidence than a single-cause account. A systematic review found that mobile or SMS reminders improved uptake, completeness, or timeliness of routine childhood immunization in some low- and middle-income settings, indicating that forgetfulness or logistical constraints can be consequential. At the same time, WHO distinguishes motivational factors from availability, affordability, service quality, social norms, and communication, and the observed association between hesitancy and non-uptake leaves demand-side interventions relevant. The principal evidence gap is the absence of a precise, comparable global estimate of vaccine hesitancy’s independent causal contribution to childhood coverage deficits. The available reviews report heterogeneous estimates and inconsistent definitions, countries, sampling methods, and survey timing, limiting conversion of measured hesitancy into a single global effect on coverage. The supplied evidence also does not resolve how much apparent hesitancy reflects confounding or overlap with convenience, trust in providers, service quality, conflict, and other access constraints. On balance, the evidence supports the conclusion that vaccine hesitancy significantly affects childhood vaccination in some countries and populations and is a material global risk, but it does not establish hesitancy as the principal cause of worldwide coverage shortfalls. Confidence in that qualified conclusion is high because systematic reviews, cross-national and institutional reporting, and pandemic-disruption evidence converge on a multi-causal account: hesitancy is linked to missed or delayed doses, while access and delivery barriers independently produce substantial non-vaccination. The dominant uncertainty is attribution: inconsistent measurement and overlapping mechanisms prevent a reliable worldwide estimate of the portion of under-vaccination caused independently by hesitancy.