100 Million Vaccine Doses Reach 18 Million Kids Worldwide

More than 100 million vaccine doses have reached children worldwide through the largest catch-up vaccination campaign ever launched, reversing one of the pandemic's most harmful health impacts.

The Big Catch-Up initiative, led by the World Health Organization, Gavi, and UNICEF, reached 18.3 million children aged one to five across 36 countries in Africa and Asia between 2023 and 2025. Of those children, 12.3 million had never received a single routine vaccine in their lives.

The program concluded on March 31, 2026, and is on track to meet its ambitious goal of reaching at least 21 million unvaccinated and under-vaccinated children. These countries account for about 60 percent of the world's "zero-dose children," a problem made worse when COVID-19 disrupted routine health services.

For the first time, health workers systematically expanded immunization programs to find and vaccinate older children aged one to five who missed their early shots. Traditional vaccination efforts typically focus only on infants, leaving millions of toddlers and preschoolers vulnerable to preventable diseases.

Ethiopia delivered remarkable results, reaching more than 2.5 million previously unvaccinated children with their first doses. The country also administered nearly 5 million polio vaccine doses and more than 4 million measles shots to children who had fallen through the cracks.

Nigeria achieved similar success, vaccinating about 2 million children for the first time and delivering 3.4 million polio doses. Twelve countries, including Kenya, Ethiopia, Somalia, Tanzania, Pakistan, and Zambia, reached more than 60 percent of their previously unvaccinated children under five.

The Ripple Effect

The campaign did more than just deliver shots. Countries trained health workers to identify missed children during routine care visits, updated vaccine policies to include older children, and partnered with local communities to spread awareness and build trust in immunization.

"The Big Catch-Up shows what is possible when governments, partners and communities work together to protect the most vulnerable in society," said Dr. Sania Nishtar, CEO of Gavi. The initiative focused on reaching children in fragile, conflict-affected, and underserved areas where access to healthcare remains challenging.

Dr. Tedros Adhanom Ghebreyesus, WHO Director-General, celebrated the campaign's success in undoing pandemic damage. "By protecting children who missed out on vaccinations because of disruptions to health services caused by COVID-19, the Big Catch-Up has helped to undo one of the pandemic's major negative consequences," he said.

Despite this progress, challenges remain. An estimated 14.3 million infants worldwide still received no vaccines in 2024, and measles cases surged to around 11 million globally that same year.

UNICEF's Catherine Russell emphasized the need for continued investment in routine immunization systems, especially as measles outbreaks triple since 2021. This historic effort proves that cooperation and commitment can protect millions of vulnerable children from preventable diseases.