By Bunmi Yekini
A global effort to restore childhood immunisation levels after the COVID-19 pandemic has delivered more than 100 million vaccine doses to an estimated 18.3 million children across 36 countries, health agencies said on Friday, while warning that millions still miss routine life-saving shots each year.
The initiative, known as the Big Catch-Up and led by Gavi, the Vaccine Alliance, World Health Organization and UNICEF, targeted children who fell behind on vaccinations during pandemic-related disruptions. It concluded in March 2026 and is on track to meet its goal of reaching at least 21 million un- and under-immunised children.
Of those reached between 2023 and 2025, around 12.3 million had never received a single vaccine, so-called “zero-dose” children, while 15 million had not been vaccinated against measles, one of the most contagious diseases. The programme also administered 23 million doses of inactivated polio vaccine, supporting global eradication efforts.
Despite the progress, agencies cautioned that catch-up campaigns alone cannot replace strong routine immunisation systems.
“While this initiative has helped close critical gaps, millions of infants still miss essential vaccines every year,” the agencies said in a joint statement marking World Immunization Week.
The 36 participating countries, mainly in Africa and Asia, account for roughly 60% of zero-dose children globally. Many live in conflict-affected or underserved areas where access to healthcare remains limited.
Countries including Burkina Faso, Ethiopia, Kenya and Pakistan reported reaching more than 60% of previously unvaccinated children under five. In Nigeria, around 2 million zero-dose children received their first diphtheria, tetanus and pertussis vaccine, alongside millions of additional doses of other vaccines.
Health officials said the programme also strengthened long-term systems by training workers to identify missed children and integrating catch-up efforts into routine services.
Tedros Adhanom Ghebreyesus said the campaign helped reverse one of the pandemic’s most damaging impacts. “The success of the Big Catch-Up is a testament to health workers and national immunisation programmes,” he said.
Still, challenges remain. In 2024 alone, an estimated 14.3 million infants globally did not receive a single routine vaccine. Measles outbreaks are rising across regions, with about 11 million cases recorded last year and a sharp increase in countries experiencing large outbreaks.
Catherine Russell warned that recent gains could be lost without sustained investment. “We’ve caught up with some children who missed vaccinations during the pandemic, but many more remain out of reach,” she said.
The agencies called for increased domestic funding and stronger health systems to ensure consistent vaccine access, particularly in fragile settings.
As countries mark World Immunization Week from April 24 to 30, officials emphasised that routine immunisation remains the most effective way to protect children and prevent future outbreaks.
“Catch-up campaigns are important,” the agencies said, “but timely vaccination is the only sustainable path to safeguarding communities for generations.”