The initiative, known as the Big Catch-Up and led by the World Health Organization, UNICEF and Gavi, the Vaccine Alliance, concluded in March after a three-year effort to restore immunization coverage disrupted by the pandemic.

By the end of December 2025, the campaign had reached an estimated 18.3 million children aged under five across 36 countries in Africa and Asia, delivering more than 100 million vaccine doses, according to a joint statement. Of those, around 12.3 million children had never received any prior vaccination, while 15 million had not previously been immunized against measles.

Health systems worldwide faced severe disruption during the COVID-19 crisis, leading to missed routine immunizations and a resurgence of preventable diseases including measles and polio. The agencies said the campaign also strengthened national immunization systems by improving their ability to identify children who had previously been missed.

Tedros Adhanom Ghebreyesus said the initiative had helped reverse one of the pandemic’s major health setbacks by reaching children who had been excluded due to service disruptions.However, officials warned that significant obstacles persist.

The agencies highlighted declining foreign aid and widening gaps in routine immunization, noting that measles outbreaks have increased globally, with approximately 11 million cases reported in 2024.Kate O’Brien said growing politicization of vaccines and health issues posed a serious concern, even as trust in frontline health workers remained relatively strong.

Sania Nishtar pointed to the role of social media in amplifying misinformation, saying digital platforms often incentivize the spread of misleading or false content about vaccines.

Ephrem Lemango added that algorithm-driven amplification of anti-vaccine narratives, combined with reductions in global health funding, could undermine progress and risk reversing gains made through the campaign.

Speaking at a Reuters Newsmaker event in New York, Gates said the world was at a crossroads, with millions of children at risk of dying if funding drops too steeply.

The Gates Foundation’s pledge matches its donation in 2022. That was the last time the Global Fund, a Geneva-based independent nonprofit, raised money on its three-year budget cycle. The announcement follows deep aid cuts from governments around the world, led by the United States.

“A kid born in northern Nigeria has a 15% chance of dying before the age of 5. You can either be part of improving that or act like that doesn’t matter,” Gates said in an interview before the foundation’s annual Goalkeepers event in New York on Monday.

The event celebrates and seeks to accelerate progress on United Nations global development goals set for 2030, including improving health and ending poverty.

“I am not capable of making up what the government cuts, and I don’t want to create an illusion of that,” he said about his pledge.

The Gates Foundation, the philanthropy started by the Microsoft co-founder and his then-wife in 2000, is one of the world’s biggest funders of global health initiatives, with a particular focus on ending preventable deaths of mothers and babies, tackling infectious diseases and lifting millions out of poverty.

Earlier this year, Gates pledged to give away almost his entire $200 billion fortune by 2045, more quickly than planned because of the urgent need worldwide.

Millions More Could Be Saved

According to the U.S.-based Institute for Health Metrics and Evaluation, global development assistance fell by 21% between 2024 and 2025 and is now at a 15-year low.

That could still change, said Gates, with organizations like the Global Fund trying to raise money before the end of the year. But if the trajectory remains the same, progress that cut child mortality in half since 2000, saving 5 million lives a year, could be in jeopardy, he said in a statement.

Gates said that there was still an opportunity to save millions of lives and end some of the deadliest childhood diseases by the time he will have donated the rest of his fortune in 2045.

That would require maintaining funding for institutions like the Global Fund as well as Gavi, the Vaccine Alliance, prioritizing primary healthcare and rolling out innovations – such as the long-acting HIV prevention drug lenacapavir – quickly.

“What’s happening to the health of the world’s children is worse than most people realize, but our long-term prospects are better than most people can imagine,” Gates said in a statement.

At the Goalkeepers event, the foundation gave Spanish Prime Minister Pedro Sánchez its annual Global Goalkeeper Award. While other countries reduced global health support, Spain increased its donations to the Global Fund this year by 12% and Gavi by 30%.

The Goalkeepers event usually involves publication of a progress report on the U.N. sustainable development goals, originally adopted in 2015. But that has been delayed until an event in Abu Dhabi in December, when global health funding will be clearer, the foundation said.