Photo: Fabio Murgia/CSIS, assets from Wikimedia Commons
The United States has long supported bilateral and multilateral immunization programs, joining partners around the world both to help prevent outbreaks of infectious diseases abroad and to limit the potential for imported cases to seed outbreaks at home. But following decades of effort to improve access to and uptake of immunizations globally and domestically, progress has been inconsistent in recent years. Focused campaigns have helped increase immunization coverage in many cases. Still, trends have reversed in others due to weak health systems, declining public confidence in vaccines, or ongoing violence or conflict that makes it challenging to deliver immunization services. Recent decisions by the United States to wind down bilateral immunization programs; terminate its support for Gavi, the Vaccine Alliance, which helps the lowest-income countries purchase vaccines; and withdraw from the World Health Organization (WHO), which provides national immunization programs with technical support, may further limit progress. The resurgence of measles and other vaccine-preventable diseases in the United States and elsewhere underscores the fragility of recent progress in disease prevention and highlights the importance of reinforcing domestic and global efforts to prevent deadly—and costly—outbreaks and protect health security.
International collaborations have been critical to strengthening immunization coverage globally. Recognizing the potential for widespread access to immunizations to reduce child mortality and protect child health, in the mid-1970s, the WHO established the Expanded Program on Immunizations (EPI). The EPI, now known as the Essential Program on Immunization, provides technical assistance to countries and supports their efforts to deliver vaccines and prevent outbreaks of infectious disease for vulnerable populations. Since its launch in 1974, the vaccines supported by the EPI are estimated to have saved more than 150 million lives, more than two-thirds of which were among infants.
To further accelerate efforts to reach children with vaccines, in 2000, international organizations, donor and implementing governments, and the private sector joined to launch Gavi, the Vaccine Alliance, with a goal of ensuring the lowest-income countries could purchase vaccines at low or no cost. The WHO, UNICEF, and World Bank are core multilateral partners, along with philanthropies, vaccine manufacturers, and public health and development agencies. Since its inception, Gavi’s support to countries has protected more than 1 billion children from vaccine-preventable diseases and has saved nearly 20 million lives.
Before the introduction of measles vaccines in the 1960s, global deaths from this highly transmissible viral infection exceeded 2.5 million annually. Over the next few decades, the introduction of measles vaccines led to dramatic decreases in mortality, accounting for 60 percent of infant lives saved. While measles vaccines were first delivered primarily in high-income countries, over time, through efforts by UNICEF, Gavi, the WHO, and other international collaborations, first and second doses of the vaccine have become more widely available to populations in low- and lower-middle-income countries. The measles vaccine has been among the core vaccines recommended by the EPI since the 1970s. Treating measles, tracing contacts, and carrying out emergency vaccination campaigns are all costly, and outbreaks point to greater gaps in the population’s access to healthcare and protection against other vaccine-preventable diseases.
Following several decades of progress in increasing global access to and uptake of vaccines, immunization coverage stalled by the late 2010s, with the WHO declaring vaccine hesitancy to be among the top 10 threats to global health in 2019. In all regions, immunization coverage decreased during the Covid-19 pandemic, as health clinics diverted resources to pandemic response or families delayed immunizing children out of fear of contracting Covid-19 at a health facility. While global campaigns to boost immunization rates have reversed some of the decline, most regions have not yet returned to pre-pandemic coverage levels, with lingering weakness in health systems, along with low rates of vaccine confidence, helping to explain some of the stalled progress in increasing coverage. At the same time, wars and civil conflicts also reduce the population’s access to health services, including immunizations, making children living in humanitarian or conflict settings especially vulnerable to vaccine-preventable diseases.
Organizations including Gavi, the WHO, UNICEF, and others have worked since 2023 through “The Big Catch-up” campaign to increase immunization coverage, but many low-income and conflict-affected countries, in particular, continue to struggle to return to 2019 levels.
Immunization coverage can drop in fragile or conflict-affected settings. Violence can make it difficult for health workers to reach populations with health services, and the destruction of health facilities means that vulnerable populations have limited options for seeking vaccinations, not to mention clinical care when children become ill.
In Sudan, which has experienced civil war since 2023, coverage with three doses of diphtheria-tetanus-pertussis vaccine given in the first year of a child’s life has fallen to below 40 percent. In Gaza, DTP3 coverage dropped following the onset of conflict in October 2023, while in Ukraine, DTP3 coverage fell during the Russian occupation of Crimea in 2014 and again after the onset of violence in 2022. Despite the challenges of war, displacement, and damage to health facilities, data from Gaza and Ukraine show that by devoting special attention to increasing delivery of services and conducting special vaccination campaigns during periods of ceasefire, it is possible to halt and reverse declines in coverage, even in situations where conflict is ongoing.
During the pandemic, supply chain constraints, lockdowns, mask mandates, and the spread of misinformation about Covid-19 origins on social media all contributed to undermining trust in vaccines, including the new mRNA technologies associated with some Covid-19 vaccines.
Public attitudes show increased skepticism toward vaccines in countries around the world. The 2023 State of the World’s Children, published by UNICEF in collaboration with the Vaccine Confidence Project, reported that in 52 out of 55 countries assessed, surveyed individuals expressed less trust in immunizations and the caregivers who provide them than before the pandemic.
According to a poll conducted by KFF between July and August 2025, parents in the United States who skipped or delayed any vaccines for their children were also more likely to believe false claims about measles vaccines. With inconsistent communication about the safety of vaccines from the nation’s top health authorities, public trust in health institutions and vaccine safety may continue to erode.
Since the Covid-19 pandemic, immunization coverage in the United States has decreased slightly, but overall numbers mask a more fragmented immunization landscape. Across the 50 states, requirements to obtain vaccination exemptions for children vary, and the rise in nonmedical vaccine exemptions across more than half of all counties in the country points to gaps in immunity within states and localities.
Although South Carolina recently declared its measles outbreak over, there are active cases in Arizona (nearly 90 cases) and Utah (more than 428 cases) that point to the continued concern about populations susceptible to the spread of infection.
Recent changes to the Advisory Committee on Immunization Practices, which issues recommendations, and efforts to expand the conditions covered in the Vaccine Injury Compensation Program, which was established in the 1980s to provide relief to people harmed by vaccines while reducing the risk of lawsuits that might push manufacturers out of business, may sow further confusion and fuel debate over the safety and utility of vaccines.
In 2000, the United States was certified as having eliminated sustained measles transmission for at least 12 months. However, since January 2025, the United States has confirmed measles outbreaks in several states across the country, leading to concerns that the elimination certification may be at risk. Cases were reported in Gaines County in West Texas in January 2025 and spread to neighboring Lea County in New Mexico. During the course of 2025, measles was reported in several other states, including Arizona, Ohio, Oklahoma, and Kansas, leading to more than 2,000 confirmed cases. More recently, outbreaks in South Carolina, Utah, Arizona, and Florida have led to nearly 1,900 cases reported since the start of 2026. In November 2026, the Pan American Health Organization (PAHO) will consider whether the United States should lose its elimination status. The United States is not alone in experiencing a spike in measles cases decades after eliminating sustained transmission. Canada lost its certification in 2025 after a nationwide outbreak with more than 5,000 cases, and Mexico confirmed nearly 6,000 measles cases the same year. The region of the Americas, which in 2025 had 6 percent of all measles cases globally, now reports more than 20 percent in the first quarter of 2026.
The United States was one of the original supporters of Gavi, the Vaccine Alliance, which was launched in 2000. Until 2025, the United States had been one of the most generous donors, as well, providing an average of 14 percent of the alliance’s budget per year, serving on the Gavi Board, and cooperating through bilateral USAID missions to support countries’ immunization efforts. In 2024, on behalf of the United States, former First Lady Jill Biden committed nearly $1.6 billion to the next Gavi replenishment to support its 2026–2030 work plan; however, Secretary of Health and Human Services Robert F. Kennedy Jr., in a video announcement at the 2025 replenishment conference, citing concerns about diphtheria-tetanus-pertussis vaccine Gavi procures on behalf of eligible countries and would not support Gavi in the current work phase. Although Congress appropriated $300 million for Gavi in the FY 2026 foreign assistance appropriations bill, the administration has not spent the FY 2025 funds appropriated by Congress for Gavi, and in January 2026, it froze all funds to the alliance. It is unclear whether new funds appropriated for Gavi in FY 2026 will be transferred to the organization.
In addition to helping low-income countries procure vaccines for use in routine immunization programs, Gavi, in coordination with the International Coordinating Group (ICG) on Vaccine Provision, the WHO, UNICEF, the International Federation of Red Cross and Red Crescent Societies (IFRC), and Doctors Without Borders, supports a vaccine stockpile to prevent infection with the Ebola virus, a deadly hemorrhagic disease.
Since 2021, the stockpile, based in Switzerland, has maintained 500,000 doses that can be rapidly shipped to any country seeking to contain an outbreak; Gavi-eligible countries receive the doses free of charge. In recent years, deployment of stockpiled doses has prevented outbreaks from expanding, reducing the likelihood of high numbers of infections and deaths as seen during the 2014–2016 Ebola outbreak in West Africa. Recent analysis suggests that the use of the Ebola vaccine stockpile, along with other outbreak response methods, such as contact tracing, helped reduce deaths due to Ebola infection by 35–55 percent between 2018 and 2022.
Last year, an Ebola outbreak was reported in the DRC in September 2025, with 53 confirmed cases. Through collaboration among national health authorities, regional and global health organizations, and international partners, the outbreak was declared over by early December. In the DRC, more than 47,000 Ebola vaccines were delivered to prevent patient contacts from being infected with the virus.
But maintaining a stockpile for a new and relatively expensive vaccine is costly. Gavi CEO Sania Nishtar has said that without full funding for 2026–2030, the alliance may need to reduce the number of emergency vaccines in the stockpile.
U.S.-based vaccine manufacturers provide a significant share of vaccine products sold domestically and overseas, including the HPV vaccine; measles, mumps, and rubella vaccine; rotavirus vaccine; and pneumococcal vaccine. Gavi CEO Sania Nishtar noted that between 2012 and 2023, the alliance had purchased more than $4 billion in vaccines from U.S. manufacturers, making U.S.-based companies the largest suppliers to Gavi. Countries procuring outside of Gavi, through UNICEF, PAHO, or directly with manufacturers, also purchase U.S.-made vaccines, as well as those produced in the United Kingdom, France, China, India, and elsewhere. Given the challenges many countries outside North America and Europe faced in securing access to new vaccines during the Covid-19 pandemic, governments in South America, Sub-Saharan Africa, and Asia have placed a high priority on fast-tracking regional vaccine manufacturing initiatives, such as the Africa Vaccine Manufacturing Accelerator. The America First Global Health Strategy, released by the Department of State in September 2025, highlights the importance of supporting U.S. innovation in foreign assistance efforts. By limiting bilateral and multilateral engagement on immunization programs and creating the possibility that fewer U.S.-produced vaccines will be purchased for domestic and global use, the U.S. government is effectively sending discouraging market signals to the vaccine industry.
This publication is made possible by the generous support of the Gates Foundation.
Commentary by Katherine E. Bliss — July 31, 2025
