Imagine a child who has never received a single vaccine. These children are among the most vulnerable in the world and account for nearly half of all deaths from preventable diseases like measles and tetanus. While global vaccination rates have improved, millions of children still miss out.
Zero-dose children often live in hard-to-reach places—remote villages, or areas affected by conflict. Others may be migrants or unregistered due to their family’s legal status. These children are not just missing out on vaccines—they’re often living in communities that face social and economic disadvantages: reaching them is critical to reducing preventable deaths and improving health equity.
The Challenge: Finding the Unseen
If zero-dose children live in such vulnerable communities, why aren’t we finding them?
Identifying these children is a major challenge, for several reasons:
- Outdated Information: Population data from censuses or administrative records is often old and unreliable.
- Urban Complexity: Families living in crowded apartments or informal housing can be hard to track in cities. Furthermore, health units in urban areas often face overcrowding and long vaccination queues, leading many people to abandon the effort.
- Specialized Tools Required: Techniques like advanced mapping software are expensive and require technical expertise.
- Stockouts: Even in places where vaccines are available, frequent shortages mean children may visit health facilities but leave unvaccinated.
These challenges make it difficult to know how many children need help and where they are.
So, how do we solve this problem?
A Smarter Way to Find Zero-Dose Children: Data Triangulation
At VillageReach, we’re using an approach called data triangulation. Think of it like solving a puzzle: instead of relying on one clue, you combine many pieces of evidence from different sources to see the whole picture. In this case, we use data from immunization campaigns, health facilities, birth records and even road access maps to locate zero-dose children.
Here’s how it works:
- Immunization Campaigns are a Goldmine of Data: Campaigns like those for measles and polio vaccinations often collect detailed information about which children were vaccinated and which were not.
- Independent Data Collection: These campaigns visit hard-to-reach areas and often provide a more accurate count of children than routine health records.
- Cross-Checking: By comparing campaign data with health system records and geographic information, we can identify gaps and locate the missing children.
DRC Equity Guide Workshop participants use the Step 1 form to gather contextual information about Lodja Health Zone. Photo credit: Timoteo Chaluco
DRC Pilot: Demonstrating the Power of Data Triangulation
VillageReach piloted data triangulation in four provinces of DRC—Equateur, Haut-Lomami, Sankuru and Tshuapa.
Here’s what we found:
- In the three provinces (Equateur, Sankuru, and Tshuapa) where we had stock level data, all health zones experienced stockouts of one key vaccine (DTP, which protects against diphtheria, tetanus and pertussis).
- Even where vaccination services existed, many children couldn’t get vaccinated because of these stockouts.
- Using triangulation, we pinpointed areas where zero-dose children were concentrated.
Our Findings
Percentage of zero-dose children in selected provinces of the DRC during the pilot project. HZ- No. of Health Zones.
Why This Matters Beyond DRC
The best part about data triangulation is that it uses existing data—it’s cost-effective and doesn’t require special tools or major technical training. It can be applied in any country with some basic data sources, such as vaccination records or reports from health campaigns.
Here’s why it’s transformative:
- Focusing Resources: With better data, governments and organizations can target their efforts where they’re needed most.
- Scaling Up: By analyzing data at the district or even health facility level, we can help ensure no child slips through the cracks.
- Addressing Root Causes: This approach also helps us understand why children aren’t getting vaccinated—whether it’s because of stockouts, poor infrastructure or social barriers.
A Future Without Zero-Dose Children
The fight to vaccinate every child is not just about improving health—it’s about giving all children a fair chance at life. Reaching zero-dose children is critical to creating a fairer, healthier world.
Gavi’s global immunization strategy aims to cut the number of zero-dose children by 25% by 2025 and 50% by 2030. To achieve this, we need to map them first—and data triangulation is an effective way to do it. By using smart, efficient tools like data triangulation, we can reach the most vulnerable and make sure they’re not left behind.
Let’s act now to create a world where zero-dose children are a thing of the past. Together, we can make it happen!