The World Health Organization (WHO) and UNICEF have raised the alarm over widening immunization gaps globally, warning that millions of children remain vulnerable to vaccine-preventable diseases.
According to new data released Tuesday, nearly 20 million infants worldwide missed at least one dose of the diphtheria, tetanus, and pertussis (DTP)-containing vaccine in 2024.
Of that number, an estimated 14.3 million were “zero-dose” children who did not receive even a single dose of any vaccine.
This figure is 4 million higher than the 2024 target required to stay on course with the Immunization Agenda 2030 and 1.4 million more than in 2019, the baseline year for tracking global vaccination progress.
While the gap remains worrying, there have been modest gains. Compared to 2023, about 171,000 more children received at least one vaccine dose, and one million more completed the full three-dose DTP series, a sign of progress by countries working to protect children despite rising challenges.
Dr Tedros Adhanom Ghebreyesus, WHO Director-General, said vaccines save lives, allowing individuals, families, communities, economies, and nations to flourish.
“It’s encouraging to see a continued increase in the number of children being vaccinated, although we still have a lot of work to do. ”
He warned, however, that drastic cuts in aid, coupled with misinformation about the safety of vaccines, threaten to unwind decades of progress.
“WHO remains committed to working with our partners to support countries to develop local solutions and increase domestic investment to reach all children with the lifesaving power of vaccines,” he added.
It noted that children often remain un- or under-vaccinated due to a combination of factors, such as limited access to immunization services, disrupted supply, conflict and instability, or misinformation about vaccines.
According to the report, 131 out of 195 countries have consistently achieved at least 90% coverage for the first dose of the diphtheria, tetanus, and pertussis (DTP) vaccine since 2019.
However, there has been no significant expansion in this high-performing group. Among countries with less than 90% coverage in 2019, only 17 have improved their rates over the past five years.
Meanwhile, 47 countries are either stagnating or declining, including 22 that previously exceeded 90% coverage but have since dropped below the threshold.
The report highlights how conflict and humanitarian crises continue to threaten immunization efforts.
“A quarter of the world’s infants live in just 26 countries affected by fragility, conflict, or humanitarian crises, yet they account for half of all unvaccinated children globally,” the report stated.
In half of these 26 countries, the number of unvaccinated children has risen from 3.6 million in 2019 to 5.4 million in 2024, emphasizing the urgent need to include immunization in all humanitarian responses.
Gavi-supported countries show progress, but challenges persist
On a positive note, immunization coverage has improved in 57 low-income countries supported by Gavi, the Vaccine Alliance, resulting in a reduction of about 600,000 un- and under-vaccinated children in the past year.
These countries are now protecting more children against more diseases than ever before, thanks to expanded access and routine coverage.
However, conflict and rapid population growth remain major obstacles, even in Gavi-supported nations. Additionally, upper-middle- and high-income countries previously known for high vaccine coverage are beginning to show signs of slippage.
Experts warn that even minor drops in immunization coverage can significantly raise the risk of disease outbreaks and further strain fragile health systems.
“The good news is that we have managed to reach more children with life-saving vaccines. But millions of children remain without protection against preventable diseases, and that should worry us all,” said UNICEF Executive Director Catherine Russell.
“We must act now with determination to overcome barriers like shrinking health budgets, fragile health systems, misinformation, and access issues due to conflict. No child should die from a disease we know how to prevent.”
Expanding vaccine access beyond DTP
Despite the challenges, several countries, particularly those backed by Gavi, continue to scale up their vaccine portfolios, introducing immunization for diseases like HPV, meningitis, pneumococcal disease, polio, and rotavirus.
A key milestone was recorded in HPV vaccine coverage: in 2024, 31% of eligible adolescent girls received at least one dose, up from 17% in 2019.
Most of these vaccinations were delivered in countries using a single-dose schedule, making the expansion more feasible.
Dr. Sania Nishtar, CEO of Gavi, the Vaccine Alliance, said in 2024, lower-income countries protected more children than ever before, with coverage rates increasing across all Gavi-supported vaccines.
“Yet population growth, fragility, and conflict present major hurdles to achieving equity, leaving the most vulnerable children and communities at risk.
“Continued commitment from governments and partners will be critical to saving lives and protecting the world from infectious disease threats,” Nishtar urged.
Measles coverage still falls short
Progress was also reported in measles immunization, with 84% of children receiving the first dose and 76% the second, a slight increase from the previous year.
An estimated 2 million additional children were reached in 2024, but the numbers still fall short of the 95% threshold needed to prevent outbreaks in every community.
The report warns that more than 30 million children remain under-protected, and the number of countries facing large-scale measles outbreaks has nearly doubled, rising from 33 in 2022 to 60 in 2024.
