Multilevel Approaches to Immunization Equity

"Resilient health care systems may be critical to building immunization equity, but people must trust health care systems, their representatives, and vaccines if they are to be immunized."

In recent years, immunisation disparities have surged due to the coronavirus 2019 (COVID-19) pandemic, armed conflicts, massive population displacement, and economic crises. Furthermore, vaccine hesitancy has increased in most countries. As a result, there were 5 million more unvaccinated children in 2021 than in 2019, global vaccination coverage estimates for 11 vaccine-preventable diseases fell for 2 years in a row for the first time since 1990, wild-type and vaccine-derived poliomyelitis cases increased in multiple countries, and large measles outbreaks occurred in Africa and Asia. This article (i) illustrates how multilevel risk factors interact to create immunisation disparities through an adapted multilevel health disparities framework and (ii) reviews published studies in diverse contexts that share recommendations for increasing vaccination coverage and equity.

As outlined here, myriad factors at multiple levels contribute to healthcare disparities. The figure above presents an adapted multilevel framework that illustrates how sample risk factors interact to impede immunisation efforts, with sample interventions addressing each risk factor. Various case studies illustrate these interactions. For example, displacement due to the Russian-Ukrainian war has limited impacted individuals' access to primary healthcare services and lead them to be complacent about routine immunisations when the priority is seeking shelter, essential goods, and employment. The potential result: reduced and inequitable vaccine uptake.

With over US$21 billion in committed funding for the 2021-2025 period, Gavi seeks to: scale up vaccine equity for migrants, displaced peoples, and other vulnerable populations (e.g., pregnant women and children); help developing countries extend and strengthen healthcare systems and services; improve sustainability of and political commitment to immunisation services; and ensure stable markets for vaccines.

The article argues that, while international groups set and fund equitable immunisation priorities, there is a need to focus on conflict zones to promote equity. Numerous studies reporting on efforts to increase vaccination coverage during protracted conflicts predate the Russia-Ukraine war and offer lessons for vaccination advocates today. For example, international organisations can assist by providing skilled staff (e.g. doctors, midwives), paying community health workers, and recruiting refugee ambassadors to successfully engage these same groups. To avoid misunderstanding and vaccination without informed consent, organisations need to convey  vaccine information to displaced persons in their preferred language. Doing so can help increase public trust in campaigns and understanding of the need for specific vaccines.

When well-staffed, stable, and accessible, healthcare systems are a cornerstone of sustainable vaccine delivery in low- and middle-income countries (LMICs). Successful systems share certain characteristics. They develop long-term goals and strategies, plan for pandemics and natural disasters, prioritise equity, harmonise with broader governance, tailor services to cultural and population preferences, empower women, and support education. Countries seeking to rebuild their healthcare systems and focus on vaccination equity might begin with these priorities in mind. The creative use of existing infrastructure can be one key to immunisation equity, as was seen during the COVID-19 pandemic in Ghana, with its history of successful yellow fever and polio eradication programmes. Officials tailored campaigns to prioritise remote areas of the country, ensuring that rural citizens who had been missed during previous yellow fever and polio campaigns would be reached during the COVID-19 effort.

The COVID-19 pandemic accelerated vaccine hesitancy around the world, creating distrust, including in contexts with numerous other pressing health concerns (e.g., low-income countries, conflict zones). However, the effect of social relationships and individual attitudes on disparities in vaccine-preventable diseases has been especially visible with an even more recent epidemic: mpox. The article describes Brazilian efforts to champion community members to build trust in mpox vaccines and health services and to minimise stigma. Partnerships with trusted messengers from affected communities to combat false claims and conspiracy theories and education of health professionals about mpox and its prevention were among the efforts to improve equity among vulnerable populations.

In conclusion: "The past few years have posed unprecedented multilevel challenges to immunization equity. Nevertheless, recent publications and position papers highlighting international equity commitments, successful vaccination campaigns in conflict zones, creative health system COVID-19 responses, and courageous community health workers offer vaccination advocates hope for progress on immunization equity in 2023 and beyond. This work can ease disparities and refocus all nations on the vaccination needs of vulnerable people groups worldwide."