Big Catch-Up initiative delivers over 100 million childhood vaccine doses

The Big Catch-Up initiative reached its conclusion in March 2026, having delivered more than 100 million vaccine doses to an estimated 18.3 million children aged 1 to 5 across 36 countries. This multi-year effort was designed to reverse the decline in routine vaccinations caused by the COVID-19 pandemic. Notably, the program reached 12.3 million “zero-dose children” who had never received any immunizations, as well as 15 million who had missed the measles vaccine. These efforts have helped close dangerous immunity gaps among vulnerable populations globally.

The project began during World Immunization Week in 2023 as a partnership between Gavi, the Vaccine Alliance, the World Health Organization (WHO), and UNICEF. It focused on repairing the damage the pandemic did to global immunization rates by combining routine services with catch-up campaigns for older children. By targeting those who had missed essential shots, the initiative worked toward a more equitable system of vaccine access.

Putting the Big Catch-Up into practice required deep coordination between governments, international health bodies, and local neighborhoods. Health workers received specialized training to track down and vaccinate children who had fallen behind, while community outreach helped build trust in the process. The program placed a high priority on reaching children in fragile or underserved areas where the risk of disease is highest, ensuring that resources went where they were most needed.

Beyond the immediate health benefits, the initiative helps reduce the broader social and economic burden of preventable illness. Increasing vaccination rates protects individual children while building the herd immunity necessary to slow the spread of infectious diseases across entire communities. This protection is a fundamental step in helping children grow up healthy and reach their full potential.

With the initiative now concluded, the focus turns to maintaining these higher coverage levels and strengthening routine immunization services. The progress made offers a chance to reinforce health systems so that all children, particularly those in historically neglected regions, continue to have access to life-saving medicine. Ongoing cooperation between governments and health organizations remains vital to ensuring these gains are not lost.