With COVID still raging across the world, the topic of immunization is receiving more attention than it has in decades. Today, the world is waiting to see if immunizations will help turn the corner and end the biggest health and humanitarian crisis in a generation. Given this, policymakers and implementers need to know what works to increase immunization rates, for whom, and at what cost.  

As part of 3ie's immunization evidence program, we supported seven impact evaluations and six formative evaluations to determine the impacts of community engagement interventions on childhood immunization uptake in low and middle-income countries. We are now synthesising findings from the formative evaluations, completing an evidence gap map (EGM) and finalizing a systematic review on this topic. Both the EGM and systematic review reveal a stark lack of evidence regarding how interventions to increase immunization affect intermediate outcomes such as caregivers’ perceptions and health workers’ skills. In addition to that, however, they offer insight that may help tackle some aspects of the current crisis.

Local context must be integrated into the design of projects and, to the extent possible, leveraged to improve outcomes. Existing facilitators of immunization, such as strong local health systems and positive attitudes towards immunization, should be built upon to increase uptake. Intervention design should account for local constraints, such as unreliable cellphone services and insufficient resources. For instance, a 3ie-funded study leveraged incentives and existing social networks in Haryana, India. The researchers consulted with the community on the design of the incentives and assessed contextual feasibility. They found that asking communities to identify information-sharers and spreading messages through them improved full immunization coverage. The evidence has prompted the state government to test the communication strategy in other districts of Haryana with diverse local constraints.

The success of community engagement interventions is also determined by strong, supportive supervision and the backing of local leaders. Engaging with these leaders in the design and delivery of an intervention may increase the impacts of community engagement interventions. This was noted in a study in Nigeria where inclusion of traditional and religious leaders in the intervention led to a decrease in the proportion of unvaccinated children.  

When included in the design and implementation of interventions, local communities may be able to support health providers in identifying bottlenecks and plausible solutions. Community leaders already have connections with hard-to-reach populations. They may know those least likely to accept vaccines, the reasons for their hesitancy, and the best ways of changing their attitudes.

However, community engagement cannot be rushed. As this study noted, some interventions need the time it takes to build trust with the people, and therefore, may take longer to achieve the intended impacts. Although the shocking scale of suffering during COVID may have necessitated quick rollout of programs in many places, understanding local contexts and gaining local support remains crucial to implementing programs effectively.       

Impressive lessons have already been learned through the rollout of smallpox, polio, and yellow fever vaccines. In future, lessons learned from the rollout of the COVID vaccines ought to be used to support ongoing immunization efforts related to DPT, polio and measles. The effective use of past lessons to inform COVID vaccination efforts as well as the lessons learned from COVID to prevent future outbreaks has the potential to save lives.