Gavi, the Vaccine Alliance, alongside global partners including the World Health Organisation and the United Nations Children’s Fund, has announced that its flagship immunisation recovery initiative, the Big Catch-Up, has delivered more than 100 million doses of life-saving vaccines to children worldwide.

The organisation, in a statement issued on Friday at the start of the 2026 World Immunisation Week, said the initiative, aimed at narrowing critical immunity gaps driven by the COVID-19 pandemic, reached an estimated 18.3 million children aged one and five across 36 countries.

The organisation said BCU, described as “a historic multi-year and multi-country effort”, reached an estimated 12.3 million children who had never received a vaccine and 15 million others who had never received a measles vaccine.

Gavi said BCU, launched during World Immunisation Week in 2023, also provided 23 million doses of inactivated polio vaccines to partially vaccinated and unvaccinated children.

“Beyond pandemic recovery, the BCU initiative focused on closing the vaccine equity gap. Millions of children every year miss the essential vaccinations they should receive before the age of one. Most of them live in fragile, conflict-affected, or underserved communities and are never caught up as they grow older,” the statement said.

“The 36 participating BCU countries across Africa and Asia currently account for 60% of all zero-dose worldwide. Pandemic-related immunisation programme disruptions exacerbated this issue, and, in these countries, added millions more zero-dose children to those who already chronically miss out,” it said.

The CEO of Gavi, the Vaccine Alliance, Sania Nishtar, described BCU’s success as proof of what is possible when governments, partners and communities unite to protect the most vulnerable people in society.

“As the largest ever international effort to reach missed children with life-saving vaccines, the Big Catch-Up shows what is possible when governments, partners and communities work together to protect the most vulnerable in society,” Ms Nishtar said.

“Thanks to this accomplishment, not only are millions of children now protected from preventable diseases, but so are their communities, for generations to come,” she said.