Across Africa, health authorities are increasingly turning to data to locate children who have never received a routine vaccine, identify underserved communities and direct immunization efforts where they are most needed.
A child who never reaches a vaccination center can easily disappear from the statistics. There is no completed vaccination schedule to flag and, in some cases, no record at all. These children are known as zero-dose children: those who have not received even the first dose of a diphtheria, tetanus and pertussis-containing vaccine through routine immunization.
The latest WHO data estimates that 6.7 million children in the African Region were zero-dose in 2024. Although the figure has fallen from previous years, it remains far above the level needed to put the continent on track towards the Immunization Agenda 2030 targets.
The challenge is therefore no longer simply to know how many children are unvaccinated. Increasingly, health programs need to know where these children are, which communities are being missed and why they remain outside the health system.
Turning numbers into a map
This is where data are taking on a new role in immunization.
Routine health information systems allow countries to compare vaccination performance across regions and districts, revealing gaps that national averages can hide. The WHO Regional Office for Africa uses data submitted through national health information systems, including DHIS2, to monitor routine immunization coverage and identify areas where vaccination remains low.
Combined with population estimates and geographical information, these data can help health authorities identify communities where children are most likely to be missed. The information can then guide outreach activities, mobile vaccination teams and catch-up interventions.
In other words, data are increasingly being used not only to measure what has been done, but to determine where health workers should go next.
This is particularly important in fragile, remote or conflict-affected communities, where children may have limited access to routine services. The WHO continues to identify weak use of data, surveillance gaps, workforce shortages and disruptions to health services among the obstacles slowing immunization progress in the region.
Beyond the database
But identifying a geographical gap is only the beginning.
A high number of zero-dose children in a particular community can have several explanations. Health facilities may be too far away. Vaccination sessions may be irregular. Families may lack information about vaccination schedules. Displacement can interrupt follow-up, while misinformation or concerns about vaccines can discourage parents from seeking services.
This is why data-driven vaccination strategies increasingly combine digital information with community-level investigation. Once a high-risk area is identified, health workers can go into communities to determine which children have been missed and understand the barriers preventing them from being vaccinated.
The response can then be adapted to the problem. A remote community may require mobile services, while an urban area with low uptake may need stronger communication and follow-up.
Catching up without losing sight of routine services
The value of targeted action was demonstrated by the Big Catch-Up, launched in
2023 by WHO, UNICEF and Gavi to recover childhood vaccinations missed during and after the COVID-19 pandemic.
By 31 March 2026, the initiative had delivered more than 100 million vaccine doses to an estimated 18.3 million children across 36 countries. Some 12.3 million of those children were zero-dose, according to WHO.
The results show what targeted efforts can achieve. Yet catch-up campaigns cannot substitute for strong routine immunization systems. In 2024, an estimated 14.3 million infants worldwide received no routine vaccine at all, demonstrating that new gaps continue to emerge even as older ones are being addressed.
For Africa, the task is therefore becoming more precise: not simply counting vaccinated children, but finding those who remain invisible to the health system.
Data can reveal where they are and help direct scarce resources towards them. But a database cannot vaccinate a child, persuade a hesitant parent or cross difficult terrain.
The final step still belongs to health workers and communities. The data may provide the map. The real measure of success is whether that map leads to a child receiving a vaccine.
