Kate O'Brien, Director of the Department of Immunization, Vaccines and Biologicals at WHO
Safeguarding children and adolescents from deadly, yet preventable diseases, such as polio, measles, diphtheria, pertussis, human papillomavirus and tetanus, among others, is the foundation of the Expanded Programme on Immunization (EPI) – saving an estimated 154 million lives and adding over 10 billion years of healthy life. Through strong partnerships and countries' commitments vaccines have reached every corner of the world and became the single greatest contribution of any health intervention to ensuring babies not only see their first birthdays but continue leading healthy lives into adulthood.
2025 marks a significant turning point for immunization efforts worldwide.
Last year, we celebrated the remarkable progress made by the global immunization community since 1974. Each year, new and under-utilized vaccines continue to be introduced in countries. In 2024, four new countries introduced HPV vaccines and 25 adopted the single-dose schedule. Additionally, Niger and Nigeria became the first countries to implement the Men5CV vaccine , a new and affordable meningococcal pentavalent conjugate vaccine, and more than 12 million doses of malaria vaccine reached 17 countries in Africa in 2024 – a pivotal moment in the fight to end malaria.
The Big Catch-up Initiative , a major vaccine co-financing initiative in collaboration with Gavi and UNICEF, began reaching children left unvaccinated as a result the pandemic. By the end of 2024, an estimated 143 million vaccine doses had been delivered to 36 countries and 10.5 million catch-up doses had already been administered. This year, an additional 104 million doses will be delivered as part of the Big Catch-up, and a new WHO global monitoring dashboard is enabling real-time data tracking to continually strengthen countries strategies and our support to them. The midway point of the Immunization Agenda 2030 is upon us. As we look towards the next five years there are challenges ahead, but the goal is more relevant than ever.
Five immunization priorities for 2025
Equity: Reaching Zero-Dose Children
Vaccine equity remains one of the most urgent global health challenges of our time. While immunization programs have made tremendous progress, millions of children worldwide remain unreached—many of whom are classified as zero-dose children, meaning they have not received a single vaccine. In 2023, 14.5 million children had received no vaccines at all, a sharp increase from 12.9 million in 2019. These children are disproportionately from marginalized communities, including those in conflict zones, remote areas, and urban slums. The gap in coverage not only fuels preventable disease outbreaks but also deepens existing inequalities in health outcomes. Closing this gap requires targeted strategies: improving supply chains, strengthening healthcare infrastructure, and addressing socioeconomic barriers that prevent families from accessing vaccination services. Achieving true equity means ensuring that no child is left behind.
Outbreaks: The Resurgence of Measles and System Strengthening
Vaccine-Preventable Disease surveillance is another pillar of global health security. From yellow fever to measles to pneumonia, early detection ensures vaccines reach those who need them most. The alarming rise in measles cases is a stark reminder of result when immunization networks are weakened. Once considered on the path to elimination in many regions, measles is resurging due to gaps in vaccine coverage. This increase is a warning signal that vaccination systems are at risk—delayed campaigns, supply chain disruptions, and weakened trust in health services have created the basis for outbreaks. Strengthening immunization programmes is not just about responding to crises but about intense work to build resilient health systems so those crises are averted in the first place. This means enhancing surveillance, ensuring robust stockpiles of vaccines, training health workers, assuring data systems are in place to drive impact and intensifying essential immunization services. A failure to act decisively now could see other vaccine-preventable diseases following the same dangerous trend.
Vaccine Confidence: Strengthening Trust Among Communities and Health Workers
Confidence in vaccines is the backbone of successful immunization efforts. The past few years have exposed both the strengths and vulnerabilities of public trust in vaccines. Misinformation, historical mistrust, and political instability threaten to erode hard-won gains. At the same time, frontline health workers—the trusted faces of vaccination—must be supported with training and resources to confidently engage with communities. Trust must be built through transparency, education, and engagement. Governments, civil society, and the private sector must work together to counter misinformation and misrepresentation, amplify accurate information, and ensure that communities feel empowered, not coerced, in vaccine decision-making.
New Vaccines: Innovation, Hope, and the Need for Strong Support
Innovation in vaccines brings immense opportunity for tackling some of the world's deadliest diseases. The introduction of new vaccines—whether for malaria, RSV, or the next pandemic threat—represents a turning point in public health. New vaccines are only as impactful as the systems that deliver them. The success of these vaccines hinges not just on their development but on their effective introduction and sustained delivery. This is where our role supporting countries is critical: ensuring that regulatory approvals, financing mechanisms, health system readiness, and community acceptance are in place. Investing in the introduction of these vaccines with the same urgency as their research and development will be key to translating scientific breakthroughs into real-world protection.
Funding and political challengers
In January, President Donald Trump signed an Executive Order indicating the United States' intent to withdraw from WHO. We remain hopeful that the US will reconsider. For decades, the partnership between the US and WHO has been instrumental in achieving historic public health milestones—from the eradication of smallpox to advancing global immunization efforts that have saved millions of lives in the US and around the world. This collaboration has protected Americans at home and abroad through disease surveillance, accelerating scientific progress, and ensuring that life-saving health interventions reach those who need them most, and shutting down outbreaks when they emerge, to limit their impact.
Global health security is a shared responsibility. Infectious diseases do not respect borders, and the challenges we face—whether responding to outbreaks, developing new vaccines, or ensuring equitable access to healthcare—require international cooperation.
WHO remains committed to its mission and will continue working with partners to strengthen global health systems. Strong leadership and sustained funding are critical to ensuring immunization programmes remain resilient. However, the political landscape for vaccines is increasingly unpredictable, putting decades of progress at risk.
Moving Forward Together: A Moment for Global Health Cooperation
Two upcoming meetings will be pivotal in providing critical guidance for future immunization policies and strategies.
The Strategic Advisory Group of Experts on Immunization (SAGE) will meet 10-13 March 2025, to advance global immunization policies and priorities. Key discussions will focus on IA2030 progress, pneumococcus vaccine schedules, varicella-zoster vaccination, new vaccine introductions, NITAG strengthening, and global polio eradication policy decisions and mpox updates. The Global Vaccine and Immunization Research Forum (March 25-27, Rio de Janeiro, Brazil) will convene experts from around the world to advance vaccine innovations, sustainable R&D investments, Artificial Intelligence applications to vaccine development, climate-related challenges to immunization, and equitable access to vaccines. Key discussions will highlight Latin American advancements, maternal and new TB vaccines, vaccine role to reduce antimicrobial resistance, and clinical trial innovations for immunization.
In closing, I want to thank Member States, partners, and all those in the global health community for the resilient commitment and focus on immunization, driven always by high quality evidence, science and impact. Now is the time to remain committed and sharpen our focus so that immunization for all is a reality.
The world has the tools, knowledge, and capacity to protect future generations through vaccines. Political will and global solidarity are more valuable than ever to make that happen.
In the words of Dr. Albert Sabin, "A scientist who is also a human being cannot rest while knowledge which might be used to reduce suffering rests on the shelf." Let's ensure that decades of progress are not left behind, but are built upon. It is in our hands. It is Humanly Possible.
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