Three years after its launch, a global initiative to vaccinate children who missed routine immunizations during the COVID-19 pandemic is on track to meet its target of reaching 21 million children, according to the United Nations. The campaign, known as “The Big Catch-Up,” has already delivered more than 100 million vaccine doses across 36 countries in Africa and Asia, protecting approximately 18.3 million children between the ages of one and five.
Announced by the World Health Organization (WHO), UNICEF, and Gavi, the Vaccine Alliance, the effort aims to reverse one of the pandemic’s most damaging side effects: the disruption of essential health services that left millions of children without protection against preventable diseases like measles and polio. As of December 2025, data collected so far shows that of the 18.3 million children reached, an estimated 12.3 million had never received any vaccine before, while 15 million had not been vaccinated against measles specifically.
The initiative comes at a critical time. Global immunization coverage had declined sharply during the pandemic years, with health systems overwhelmed and routine outreach programs suspended. In its wake, outbreaks of measles and poliomyelitis resurged in regions where transmission had previously been under control. By mid-2024, more than 1.4 million children in the Americas alone had missed routine vaccinations, underscoring the uneven but widespread nature of the setback.
Despite these challenges, “The Big Catch-Up” has demonstrated measurable progress. Health workers have conducted door-to-door campaigns in remote and underserved areas, administering life-saving vaccines including those for diphtheria, tetanus, pertussis, hepatitis B, Haemophilus influenzae type b, and inactivated poliovirus. The scale of the operation — over 100 million doses delivered — reflects one of the largest coordinated immunization efforts since the global polio eradication push began decades ago.
Dr. Tedros Adhanom Ghebreyesus, Director-General of the WHO, emphasized the importance of the campaign in restoring public health gains. “By protecting children who missed vaccines due to disruptions in health services caused by COVID-19, ‘The Big Catch-Up’ has helped reverse one of the major negative consequences of the pandemic,” he stated in a joint press release with UNICEF and Gavi.
However, officials caution that the gains remain fragile. Declining donor funding, coupled with rising vaccine misinformation, threatens to undermine years of progress. In several regions, public trust in immunization has eroded, making community engagement and local outreach as vital as the vaccines themselves. The success of the initiative now depends not only on supply chains and cold storage but also on sustained political will and accurate public communication.
Although the three-year timeframe for the campaign concluded in March 2026, final data collection and analysis are ongoing. Preliminary figures released in late December 2025 indicate strong momentum, but authorities stress that reaching the final 2.7 million children to hit the 21 million target will require continued effort, particularly in conflict-affected and hard-to-access zones.
Looking ahead, global health agencies are integrating the lessons of “The Big Catch-Up” into long-term strategies for immunization recovery. These include strengthening primary healthcare systems, improving vaccine demand through community dialogue, and building more resilient supply networks capable of withstanding future disruptions. The ultimate goal extends beyond catching up: it is to ensure that no child is left behind in the pursuit of universal vaccine coverage.
For the latest updates on global immunization efforts and progress toward the 2030 Immunization Agenda, readers can consult the official dashboards maintained by the WHO and UNICEF, which are updated quarterly with country-specific data on vaccine coverage and disease surveillance.
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