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Introduction

Immunization against disease is among the most successful global health efforts of the modern era, and substantial gains in vaccination coverage rates have been achieved worldwide. However, that progress has stagnated in recent years, leaving an estimated 20 million children worldwide either undervaccinated or completely unvaccinated (UNICEF, 2020). The determinants of vaccination uptake are complex, mutable, and context specific. A primary driver is vaccine hesitancy—defined as a “delay in acceptance or refusal of vaccines despite availability of vaccination services”—which was identified by the World Health Organization (WHO) as one of the top 10 threats to global health in 2019 (WHO, 2019). While there exists a vocal minority of people who are entirely opposed to vaccination, the majority of vaccine-hesitant people fall somewhere on a spectrum from vaccine acceptance to vaccine denial. Vaccine uptake is also hampered by socioeconomic or structural barriers to access. Targeted approaches are needed to mitigate barriers to accessing routine and pandemic-related vaccination services, build trust between patients and providers to encourage effective communication about vaccines, and dispel the myths and misinformation that erode public confidence in vaccines (CDC NCIRD, 2019).

The Forum on Microbial Threats convenes workshops spanning a range of issues related to infectious diseases, from their economic drivers (NASEM, 2018) to their convergence with noncommunicable diseases (NASEM, 2019a) to the frontiers of innovation to counter microbial threats (NASEM, 2020), including antimicrobial resistance (NASEM, 2017). In 2018, the forum examined the state of national and international readiness for pandemic threats in a workshop that explored lessons

learned a century after the 1918 influenza pandemic, which seems prescient in hindsight (NASEM, 2019b). To tackle the entwined issues of vaccine access and hesitancy, in August 2020 in the midst of the global pandemic of coronavirus disease 2019 (COVID-19), the disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the forum convened this second workshop in a series focused on the critical public health value of vaccines and strategies.

The issues of vaccine confidence, access, and uptake have never been more critical or pressing, given that ending the pandemic will likely hinge on the deployment of a safe and effective vaccine on an unprecedented scale in the United States and worldwide. However, public concerns about the vaccine—which are exacerbated by misinformation and distrust—continue to be a feature of its distribution. This has brought new urgency to the need for effective approaches to build vaccine confidence, address access barriers, and encourage uptake. The pandemic has disrupted the supply chain for vaccines and, in many settings, has interrupted or halted routine immunization programs for people of all ages. Examples of these interrupted vaccination services include childhood vaccinations (Santoli et al., 2020), the human papillomavirus vaccination (Gilkey et al., 2020), and those for vaccine-preventable diseases. The COVID-19 pandemic is also likely to affect vaccine uptake during seasonal influenza vaccination season, which already varies widely by state (Wexler et al., 2020).

WORKSHOP OBJECTIVES

On August 17–20, 2020, a planning committee convened by the Forum on Microbial Threats at the National Academies of Sciences, Engineering, and Medicine held a 4-day virtual workshop titled The Critical Public Health Value of Vaccines: Tackling Issues of Access and Hesitancy.¹ This workshop was the second of a series of two workshops on the critical value of vaccines. The workshop gave particular consideration to health systems, research opportunities, communication strategies, and policies that could be considered to address access, perception, attitudes, and behaviors toward vaccination. The workshop featured presentations on two main topic areas: vaccine access and vaccine confidence. Specific topics included the following:²

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¹ The planning committee’s role was limited to planning the workshop, and the Proceedings of a Workshop was prepared by the workshop rapporteurs as a factual summary of what occurred at the workshop. Statements, recommendations, and opinions expressed are those of individual presenters and participants and are not necessarily endorsed or verified by the National Academies of Sciences, Engineering, and Medicine, and they should not be construed as reflecting any group consensus.

² The full Statement of Task is available in Appendix A.

• The global impact of declining immunization rates on vaccine-preventable diseases from lack of access;
• Trends and indicators used to monitor attitudes surrounding vaccine safety and efficacy, including a focus on regional and cultural differences;
• The complex determinants of vaccination that hinder or promote vaccine uptake;
• The role of health systems and professionals in improving access, influencing vaccine behavior, protecting at-risk communities from vaccine-preventable disease outbreaks, and preserving and building confidence in immunization strategies and practices;
• The role of media, anti-vaccine networks, and online misinformation in reinforcing anxieties about vaccine safety and drivers of vaccine hesitancy;
• Communication approaches that could help assuage anxieties about vaccine safety and strengthen public trust in science and health professionals;
• The ethics and effectiveness of legislation that aims to address vaccine hesitancy; and
• Potential priority actions—as well as partnerships and collaborations among policy makers, health professionals, national and international health organizations, parents, and community groups—to increase immunization access and vaccine confidence.

ORGANIZATION OF THE PROCEEDINGS OF THE WORKSHOP

In accordance with the policies of the National Academies, this Proceedings of a Workshop will not attempt to establish any conclusions or recommendations about needs and future directions, focusing instead on information presented, questions raised, and improvements suggested by individual workshop participants. Chapter 2 presents the workshop’s two keynote addresses, which addressed the effect of the COVID-19 pandemic on vaccination uptake and access, the state of global vaccine confidence, and strategies to counter vaccine hesitancy. Chapter 3 assesses the current state of vaccine-preventable diseases worldwide and examines approaches to improve access to vaccines and close the global immunization gap. Chapter 4 focuses on the global and local drivers along the continuum of vaccine hesitancy that affect vaccine behavior. Chapters 5 and 6 explore opportunities to employ a systems approach to building confidence and increasing uptake and includes a legal perspective of vaccination policies, with Chapter 5 examining opportunities in research, communication, legislation, and technology and Chapter 6 focusing on community-based approaches. Chapter 7 summarizes the plenary presentation on new vaccines in the midst of an

outbreak, a panel on inoculating against misinformation and rebuilding the public’s trust, and visionary statements on priorities in building vaccine acceptance and uptake for the next generation.