Why 100 Million Kids Just Got Vaccinated—and What It Means for Your Child’s Future

GENEVA/NEW YORK, 24 April 2026 – A significant international health initiative, the Big Catch-Up (BCU), has successfully provided over 100 million vaccine doses to approximately 18.3 million children aged 1 to 5 across 36 countries, according to announcements made by Gavi, the Vaccine Alliance, the World Health Organization (WHO), and UNICEF as part of World Immunization Week. Launched in 2023, this multi-year effort aims to address vaccination declines exacerbated by the COVID-19 pandemic.

Of the children reached, around 12.3 million were classified as “zero-dose children,” meaning they had not received any vaccinations prior to this initiative. Additionally, 15 million had never been vaccinated against measles. The program, which is set to conclude in March 2026, is on track to meet its ambitious target of vaccinating at least 21 million un- and under-immunized children. However, experts caution that despite these efforts, many infants continue to miss out on essential vaccines each year.

The Big Catch-Up initiative has not only focused on immediate vaccination needs but also aimed to close the vaccine equity gap. Millions of children globally miss critical vaccinations before their first birthday, with many living in fragile or conflict-affected areas, where health services are limited. This program is particularly vital as the 36 countries involved account for about 60 percent of all zero-dose children worldwide.

Gavi, WHO, and UNICEF highlighted that pandemic-related disruptions intensified existing immunization challenges, making it crucial to reach older children, aged 1 to 5, who had missed earlier vaccinations. The BCU leveraged routine immunization systems to facilitate this outreach, marking a significant shift in vaccination strategies. For the first time, health systems were encouraged to actively identify and vaccinate older children who were previously overlooked.

The initiative has led to the implementation of sustainable systems for identifying, screening, vaccinating, and monitoring coverage rates among these older children. Health workers received training to effectively engage with communities and ensure missed children were caught up on vaccinations. For instance, twelve countries— including Burkina Faso, Ethiopia, Kenya, and Nigeria—reported vaccinating more than 60 percent of zero-dose children under five who missed the DTP1 vaccine.

Ethiopia alone managed to vaccinate over 2.5 million previously zero-dose children with DTP1, in addition to providing nearly 5 million doses of the inactivated polio vaccine (IPV) and more than 4 million measles vaccines. In Nigeria, approximately 2 million previously unvaccinated children received DTP1, demonstrating that substantial progress is possible when governments and health organizations work collaboratively.

Dr. Sania Nishtar, CEO of Gavi, remarked, “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.”

Despite the successes of the BCU, challenges remain. In 2024, an estimated 14.3 million infants globally are projected to miss out on their first vaccinations through routine immunization programs. Dr. Tedros Adhanom Ghebreyesus, Director-General of the WHO, emphasized the importance of these efforts, stating, “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.”

As the world prepares for World Immunization Week, which runs from April 24 to 30, 2026, WHO, UNICEF, and Gavi are urging continued investment in vaccination programs, particularly in underserved communities. The joint campaign, titled "For every generation, vaccines work," aims to sustain and expand vaccination coverage, emphasizing the need for lasting commitment from countries and donors alike.

As history has shown, large-scale vaccination initiatives are resource-intensive and should complement, not replace, routine immunization programs. The recent surge in measles cases, with around 11 million reported globally in 2024, underscores the critical need for regular vaccinations. As the BCU has illustrated, protecting the health of children now is essential for safeguarding entire communities in the future.