Vaccine hesitancy is a delay in acceptance or refusal of vaccines despite availability, is one of the top ten threats to global health.
The phenomenon exists on a spectrum from complete acceptance to outright refusal, with most hesitant individuals experiencing ambivalence rather than absolute opposition.
Is is estimated that 154 million deaths have been averted, improving infant survival during the past 50 years.
The spectrum—from mild doubt to firm rejection varies by vaccine type (e.g., routine childhood vaccines vs. annual flu or COVID-19 shots), time, place, and individual factors.
Vaccine hesitancy refers to a delay in acceptance or outright refusal of vaccines despite their availability and strong evidence of safety and effectiveness.
The World Health Organization lists vaccine hesitancy among top global health threats because it can erode herd immunity, typically needing ~95% coverage for highly contagious diseases like measles, and allow preventable outbreaks.
The primary drivers of vaccine hesitancy: The most prevalent factor globally is lack of trust in vaccines/authorities/pharmaceutical companies, perceived lack of need for vaccination, and cultural or religious reasons.
A global meta-analysis found that 25% of caregivers worldwide exhibit vaccine hesitancy, with vaccine safety and efficacy concerns identified as the main factor in 91.4% of cases.
The World Health Organization organizes determinants into three domains:
Influences include the communication and media environment, political factors, religious and cultural beliefs, socioeconomic status, and perceptions of the pharmaceutical industry.
Amplified vaccine hesitancy occurs through rapid spread of misinformation alongside accurate information.
Individual and group influences include personal experiences with vaccination, beliefs about health and prevention, trust in healthcare providers, risk-benefit perceptions, and whether vaccination is viewed as a social norm.
Distrust of medical systems are strongly associated with hesitancy.
For COVID-19 vaccines specifically, the strongest correlates of hesitancy were mistrust of vaccine benefit and lower perceived seriousness of COVID-19, which together explained substantial variance in hesitancy.
Political affiliation, particularly right-wing views, emerged as a significant factor, along with belief in misinformation and conspiracy theories.
A study from England found that the most prevalent reasons for COVID-19 vaccine hesitancy were concerns about long-term health effects (40.7%), wanting to wait and see how well the vaccine worked (38.9%), and worries about side-effects (36.8%).
Consequences of vaccine hesitancy include outbreaks of vaccine-preventable diseases such as measles, pertussis, Haemophilus influenzae type b, varicella, and pneumococcal disease.
Geographic clustering of vaccine refusal increases outbreak risk even when overall vaccination rates remain high.
Addressing vaccine hesitancy requires targeted messaging from trusted sources, transparent communication about vaccine safety and effectiveness, adequate time for vaccine risk communication in clinical settings, and interventions tailored to specific communities and concerns.
Pharmaceutical companies are not viewed as trusted information sources.
Current Trends
Childhood vaccination rates in the U.S. have declined since the pre-pandemic era.
For the 2024-2025 school year, kindergarten coverage for MMR, DTaP, and polio fell to around 92-93%, below the 95% target in many areas, with 77% of U.S. counties showing notable drops since 2019.
Non-medical exemptions rose to 3.6% nationally and is the highest on record, driven largely by philosophical or personal belief exemptions.
Measles cases surged in 2025, with the U.S. reporting far more cases in the first half of the year than in recent decades, including a major outbreak in Texas.
Globally, measles cases reached ~10.3 million in 2023 and continued rising, with outbreaks in over 100 countries.
Adult uptake for seasonal vaccines remains lower.
As of January 2026, only ~44% of U.S. adults received the 2025-26 flu shot, ~16% got the updated COVID-19 vaccine, and RSV vaccination among older adults was even more limited.
Hesitancy has increased post-COVID, fueled by shifts in public messaging, leadership changes at health agencies, and widespread misinformation.
Surveys show ~84% of Americans still express confidence in childhood vaccine effectiveness overall, but doubts about safety, necessity, or the number of shots on the schedule have grown—particularly among some political subgroups and younger parents.
Many initially hesitant individuals (especially regarding COVID-19 vaccines) eventually vaccinated as concerns about effectiveness or side effects eased with real-world data, but a persistent minority remains firm.
Common Reasons for Hesitancy;
Confidence (trust in vaccines, developers, and systems)
Complacency (low perceived risk of disease)
Convenience (access, cost, logistics).
Key drivers include: Safety and side-effect concerns: Fears of rare adverse events, unknown long-term effects, or ingredients (aluminum, thimerosal).
For newer vaccines like COVID-19 mRNA ones, rapid development raised questions: trials and billions of doses worldwide show serious risks are rare (e.g., myocarditis far more common/severe after infection than vaccination).
Efficacy and necessity doubts:
Belief that natural infection provides better immunity, diseases aren’t serious, or too many vaccines overwhelm the immune system.
Misinformation and social media:
Claims linking MMR to autism, COVID vaccines causing infertility or microchips/tracking.
Social media amplifies these faster than corrections; exposure to misinformation can reduce intent to vaccinate even among previously accepting people.
Distrust in institutions/pharma/government.
Historical events, perceived conflicts of interest, rapid policy shifts during COVID, or politicization eroded confidence.
Trust in healthcare providers remains one of the strongest predictors of uptake.
Cultural, religious, or ideological factors. Views on bodily autonomy, natural immunity preference, or compatibility with beliefs.
Political ideology and conspiratorial thinking correlate with higher hesitancy in some analyses.
Demographic patterns: Higher in some groups by education, income, age, gender, or prior experiences.
Concerns about too many shots or side effects for children.
Parents sometimes cite personal/family anecdotes over population-level data.
Low perceived disease risk (complacency) rises when outbreaks are rare due to past high vaccination rates-success hides the problem.
Rigorous systems confirm vaccines undergo extensive testing.
They have prevented millions of deaths annually; global estimates credit them with saving over 150 million lives in recent decades through reduced mortality from diseases like measles, polio, and diphtheria.
Benefits far outweigh risks for recommended vaccines in most populations.
Rare side effects are monitored transparently, schedules are designed based on disease epidemiology, immune response timing, and safety data.
Claims of widespread harm lack support in high-quality evidence and are contradicted by epidemiological data.
Autism rates do not differ by vaccination status, and genetic factors play the primary role, onset often prenatal.
Outbreaks consistently cluster in under-vaccinated communities.
Most hesitancy is not absolute refusal as many respond to dialogue.
Evidence-based approaches include:
Strong, presumptive opinions from trusted clinicians outperforms passive offers.
Motivational interviewing: Open, non-judgmental conversations exploring specific concerns rather than lecturing or shaming.
Clear communication: Acknowledging kernel of truth in concern, correcting misinformation, reinforcing and focusing on protecting loved ones/community.
Access improvements: Free/low-cost vaccines, convenient locations of pharmacies, reminders.
Community and media strategies: Engaging local leaders, countering misinformation proactively and transparent data sharing.