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Protecting children is a shared responsibility, says health and rehabilitation sciences PhD candidate Meron Mengistu. As a graduate researcher in the Faculty of Health Sciences, her work focuses on improving childhood vaccination rates across the globe.
While vaccine hesitancy and anti-vaccination movements often make headlines, Mengistu’s work shows there are multiple and layered reasons why children may not receive vaccinations globally – including lack of transportation, living in conflict zones, misinformation and more.
She spoke to Western News about her recent research evaluating strategies to improve childhood vaccination rates worldwide.
Western News: Why does childhood vaccination matter? At the individual and societal level?
Meron Mengistu (MM): There are two main reasons why childhood vaccination matters. Vaccination can reduce the spread of many infectious diseases and may also help protect people who cannot be vaccinated or who may not develop a strong immune response themselves. Think of measles, polio, tuberculosis, or hepatitis. Children under five, specifically, are even more vulnerable because their immune systems are still developing, so they may not be able to fight infections as effectively as older children or adults.
“Infectious diseases don’t conform to borders or cultures or socioeconomic status. As long as conditions allow, diseases will spread quickly from person to person and community to community. Vaccination helps reduce spread and protect not only vaccinated children but other children and individuals who cannot be vaccinated or who may not develop a strong immune response. Protecting children is a shared responsibility.” – Meron Mengistu, PhD candidate in health and rehabilitation sciences
Their right to health and wellbeing is reflected in national and international commitments.
What is the current global vaccination coverage rate for children under five and what is the goal?
MM: There isn’t a single global coverage rate that captures all childhood vaccines but there is a benchmark of coverage: the third dose of a vaccine we call diphtheria-tetanus-pertussis, or DTP-3, among children around one year of age.
Based on the latest available global estimates from 2025, about 85 per cent of infants worldwide received all three DTP doses. The Immunization Agenda 2030 aims to increase coverage of DTP–3 to at least 90 per cent. Approximately 13.5 million children were classified as “zero-dose,” meaning they had not received the first dose of a DTP-containing vaccine. So, while 85 per cent sounds pretty good, there are still a significant number of infants missed.
What are the barriers to vaccination? Why might children not receive their vaccinations?
MM: There are so many reasons why a child might not receive vaccines and oftentimes these barriers overlap.
Let’s start at the household level. When we’re talking about children, we’re oftentimes also talking about caregivers – because they are the primary individuals making decisions on vaccination. Caregivers might have difficulty reaching vaccination services because of long distances, cost associated with seeking services, or work responsibilities. Vaccination decisions may also depend on support from a spouse or family member, as well.
At the community level, there are persistent issues of local beliefs and attitudes. There may be concerns about vaccine safety, misinformation, rumours, mistrust — especially mistrust of the intentions behind vaccines and manufacturers, which has become a bigger issue. Some caregivers may prefer traditional healing approaches or may wish to try them before seeking vaccination.
There are also health facility or health-care-level barriers that may hinder vaccination. A vaccine might be out of stock, the clinic might be understaffed or have long wait times.
Lastly, we have broader health system factors like limited funding for health care and barriers to access, such as rough roads, underdeveloped infrastructure, weather or conflict that could pose challenges.
Your investigation into childhood vaccination identified four distinct types of strategies that could help improve uptake. Can you describe each category and provide some specific examples?
MM: We grouped strategies using a mechanism-based lens. In simple terms, this means we categorized each strategy by where it acted and what it was primarily trying to address.
Demand-level strategies targeted caregivers and communities to increase uptake. Examples include sending text reminders about upcoming appointments for vaccines or educational sessions on vaccination benefits and when your child should get vaccinated. Another example was cash incentives for completing vaccinations.
Service delivery-level strategies focused on how and where vaccination services were being provided. Examples included a mobile vaccination clinic as well as communication training for health-care workers to improve how they interacted with communities.
The third category was system level, which addressed things like structures or systems. One specific example was enacting a policy that linked vaccination status to enrolment in childcare or kindergarten.
Multi-level strategies simply combined the different types. For example, a strategy where they combined text message reminders or phone call reminders with health-care workers having the ability to download a mobile app to schedule appointments and track vaccinations.
What strategies show the most promising impact in Canada? Internationally?
MM: I really love this question because it really challenged me to think of the lessons we’ve learned. Through leading this research, I saw the value of its international scope and learned how important context really is.
In Canada, there was evidence from one study conducted in Saskatoon, where they tested telephone reminders, and in selected neighbourhoods, also? offered home-based measles-mumps-rubella (MMR) vaccination. So this was a multi-level strategy. They reported an increase of MMR immunization coverage of approximately seven percentage points following telephone reminders, from 67.4 to 74 per cent, which was quite promising. The offer of home visits was also associated with higher coverage, although the effect was not statistically significant.
This approach may be particularly relevant in Canada because telephone access is quite widespread, although not universal, and home-based services may help reduce access barriers for some rural, remote and underserved populations.
Internationally, several strategies showed promise. Cash incentives produced small but consistent improvement in full vaccination coverage, although evidence only came from two countries, both lower-middle income. Informational sessions also improved coverage for later vaccine doses, but results varied across studies, making the overall size of the benefit uncertain.
No single strategy worked the same across settings. The strongest takeaway is that the effectiveness depended on context, and the barriers or needs of that population.
Are there any newer strategies that have yet to be tested but could prove more successful?
MM: This is something I’m exploring in my current study in the East African context where participants have shared examples of strategies, including digital tools, to strengthen vaccine communication and decision-making.
For example, in Kenya they have a rumour-tracking tool that looks at social media messages. This was first introduced to track information gaps and respond to misinformation about COVID-19 vaccines. Digital tools could also support the tracking of highly mobile populations, improve information sharing across different levels of the health system, and allow data to reach decision-makers more quickly.
Another opportunity involves co-designing strategies with caregivers, communities and health-care workers to ensure that the strategies respond to local needs and fit the local context.
How can your findings be used to improve vaccination coverage rates?
MM: First, prioritizing further evaluation of strategies with the most consistent evidence. Second, the findings can help programs match the strategy based on the reasons why children are not being vaccinated. Third, the study helps position the next generation of research.
The main message isn’t really to copy and paste one intervention; it’s to use the evidence to select an approach that matches the local needs, resources and challenges.
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