COVID-19 and Routine Childhood Immunization in Africa: Leveraging Systems Thinking and Implementation Science to Improve Immunization System Performance

One of the routine health services that is being disrupted by COVID-19 is childhood immunisation. Africa is of particular concern because the performance of immunisation programmes on the continent even in the pre-COVID-19 era was largely sub-optimal. Nigeria and South Africa are among the countries that are expected to have the highest numbers of COVID-19 cases, and the diphtheria-tetanus-pertussis-containing vaccine (DTP3) coverage level in these countries was reported to be 57% and 74%, respectively, in 2019. In this worrisome context, this article is premised on the belief that, instead of studying individual components of the immunisation system (e.g., vaccine supply and logistics), a systems-based approach that conceptualises all components of the system as interrelated entities should be adopted.

As an example, the causal loop diagram (CLD) shown above was constructed to illustrate the relationship between COVID-19, its control strategies, and immunisation. The model reveals the linkage between COVID-19 cases and lockdown as a balancing loop. For instance, it shows how lockdown can directly affect immunisation services by constraining access to vaccines. The presence of roadblocks dissuades caregivers from visiting health facilities for routine immunisation. In addition, community mobilisation activities inevitably decrease due to the risk of transmission they pose, with a resultant decrease in mass vaccination campaigns.

This simple CLD demonstrates that many elements are interacting with the immunisation systems and that a change in one part of the system causes a cascade of changes in other parts. The authors contend that using this to guide planning and the prioritization of areas for intervention could pave the way for system re-design and improvement.

Specifically, implementation science concepts can be used to:

• Reinforce the importance of tailoring information needs to meet the demands of different stakeholders. Community members are prone to misinformation about COVID-19, and there is a risk that vaccine hesitancy among caregivers could increase. To address this, appropriately tailored information about the novel disease, including recommended preventive strategies like use of a face mask when in public, could be communicated with community members. In addition, the importance of infant immunisation could be re-emphasised to motivate caregivers to continue scheduled immunisation visits.
• Ensure consideration of context in COVID-19-related policies. For example, existing structures like patent medicine vendors can be engaged to provide immunisation services in slums and hard-to-reach areas when health facilities are overwhelmed. And to ease caregiver movement through roadblocks and promote adherence to the immunisation schedule, the child home-based record could be regarded as a "pass".
• Support immunisation system re-design by accelerating the uptake and use of multifaceted evidence-based strategies to adjust system performance to better deal with the pressures of COVID-19. For example, tailored implementation strategies could be used to improve the adoption, implementation, and scale-up of personal protective equipment (PPE) among workers in immunisation clinics.

"In conclusion, integrating systems thinking and implementation science in health planning and decision-making could help African countries gain a better understanding of the influence of COVID-19 on health programmes, such as childhood immunization, and facilitate the implementation of multifaceted evidence-based strategies in complex practice settings."