Statement of the Problem

Vaccination was named by the US Centers for Disease Control and Prevention (CDC) as one of the top ten public health achievements of the 20th century and a recent World Health Organization brief estimate that, globally, over 154 million lives have been saved from vaccine-preventable disease (VPD) by vaccines, of which 101 million of these lives saved were infants. However, recent declines in routine childhood vaccination rates, well below protective herd immunity rates, have contributed to an increase in the prevalence and more rapid spread of childhood vaccine-preventable infectious diseases worldwide. While the reasons for these declines are complicated, in this brief, we concentrate on vaccine hesitancy using measles as an example. The WHO Strategic Advisory Group of Experts on Immunization (SAGE)SAGE Working Group on Vaccine Hesitancy defines vaccine hesitancy as a delay in acceptance or refusal of vaccination despite the availability of vaccination services.

Recent Trends

Routine childhood vaccination rates have declined in recent years. For example, in the United States, routine vaccination among kindergarten students has continued to drop from 95% coverage in the 2019-2020 school year. During the 2023–24 school year, coverage was under 93% for all reported vaccines. The exemption rate increased to 3.3%, the highest level ever recorded, potentially leaving more than 280,000 kindergartners (7.3 % of that age group) at risk of contracting measles.ii While much media attention has been focused on vaccine coverage decreases in the US, similar trends are being seen worldwide. In 2023, global vaccination coverage for the first dose of measles vaccine dropped to 83%, and over 14.5 million children under the age of one year did not receive basic vaccines, nearly 2.7 million more than at the start of the COVID-19 pandemic. From 2019 to 2023, the number of children globally missing any measles vaccination increased by 15% to 22.2 million. The 2019-2023 trend is due in part to lack of access during the COVID-19 pandemic and in part to a surge in misinformation (unintended), disinformation (intended), and anti-vaccine sentiments rapidly spread on social and other media, now commonly referred to as the “Infodemic”.

Importantly, childhood measles vaccination rates may also protect other at-risk populations. Children under the age of five years, older people, pregnant people, and those who are immunocompromised are also at higher risk of severe outcomes following measles infection.

Measles

Measles is one of the most transmissible VPDs; each infected person can spread measles to 12 to 18 susceptible individuals. Based on this high transmission rate, estimates are that 95% of a population needs to be immune to stop transmission. As of February 2025, 57 countries reported measles outbreaks, with the European Region reporting the highest number of measles cases in 2024 in over 25 years. The United States is currently experiencing a large measles outbreak in Texas that has spread to at least three states with unlinked cases in 19 other US jurisdictions. The number of US measles cases in 2025 is already higher than seen each year since 2019.vii Canada is currently experiencing measles outbreaks in British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, and Quebec, with the Canadian province of Ontario seeing its largest outbreak since 1989 . Three US deaths from the 2025 measles outbreakvii add to the growing global death toll, with 38 measles deaths in World Health Organization (WHO) European region in 2024, and reports of an average of one child dying every day from measles in Afghanistan so far in 2025 . In 2023, globally, an estimated 107,500 children died from measles, most un- or under-vaccinated.

Vaccine Hesitancy

Individual and community vaccine hesitancy (including vaccine refusal) is complicated by an interplay between systemic barriers and individual-level barriers. In this brief, we focus on factors (or influences) that operate at the individual level. Individual barriers to vaccination include but are not limited to : a) lack of resources to obtain needed medical care, b) lack of knowledge about vaccines and what constitutes the “evidence” that vaccines are effective, c) mistrust of healthcare and pharmaceutical industries, d) governmental mistrust, including public health authorities, and e) fear of harm from vaccines. These individual-level barriers are often further amplified by systemic barriers such as the actions of governments in the past and present (including failure to prevent harm), and official sanctioning of discriminatory and illegal actions based on race, ethnicity, religious affiliation, and/or social class which may operate to exacerbate these ‘individual-level’ barriers. Further action steps for clinicians are discussed in detail in the Red Book from the Committee on Infectious Diseases, American Academy of Pediatrics :

Recommended Actions

Strategies to improve childhood routine vaccination rates globally must be taken to protect children and vulnerable populations. The International Network for Epidemiology in Policy strongly supports the following institutional and governmental action steps:

1. Vaccine Schedule Communication. Public health programs that provide funding for vaccines, as well as clear communication from clinical and public health practitioners regarding major recommended vaccine schedules (including catch-up schedules) for children and adults.

2. Strong Community-Based Collaborations. Public health programs that provide funding for strong community-based collaborations between public health professionals founded on well-founded community engagement principles that include educating public health professionals through listening to community concerns–e.g., listening circles. Programs to encourage, train, and deploy immunization champions can help in this effort.

3. Public-Private Partnerships. Public-private partnerships for media (social & traditional) campaigns that clearly communicate risk information and benefits of vaccination, acknowledge and address major community concerns, and improve health literacy in sensitive and culturally appropriate ways.

4. Increase in Evidence-Based Interventions. Increased funding for evidence-based public information interventions that improve health literacy and counter harmful disinformation. Successful efforts that improve vaccination rates to protect communities depend on implementing multi-component (more than one effective) community-level interventions.

5. Expanded Multi-Disciplinary Research. Increased funding for multidisciplinary research investigating the intentional spread of anti-vaccination disinformation, including its funding sources and techniques, and effective strategies to counter this.

6. Continuing Education for Practitioners. Continuing education for public health and clinical practitioners for up-to-date training in the weight of evidence regarding vaccines, community health workers to work within communities with low vaccination rates to disseminate information on vaccine safety and efficacy.

7. Consider the Role of Exemptions. Strengthen lenient guidelines for vaccine exemptions based on religious, personal beliefs, or philosophical objections and address political and other barriers to implementation to reduce vaccine rejection and complacency.