Challenges and strategies for sustainable and resilient immunization systems in sub-Saharan Africa: A comprehensive scoping review.

Background: Immunization is pivotal for health-related sustainable development, necessitating resilient and sustainable immunization systems. This scoping review explores challenges and strategies for sustained vaccine uptake in the new Decade of Vaccines (2021-2030) within sub-Saharan Africa, encompassing routine and non-routine vaccines.

Methods: The review followed the Joanna Briggs Institute's methodology to examine English-language articles published from January 01, 2021, to May 29, 2023. Databases including PubMed, CINAHL, Cochrane Library, Embase, Medline, Scopus, and Web of Science were searched. An extended search and analysis were conducted on PubMed from May 30, 2023, to April 27, 2024, to provide an overview of information not covered within the original search period. Two independent reviewers screened articles by title and abstract, followed by a full-text review. Thematic analysis was applied to extracted data, with results presented in tabular and schematic formats.

Results: African immunization systems face numerous challenges, including high hesitancy for new and non-routine vaccines, inadequate program coordination and vaccine infrastructure, persisting social disparities in vaccine access and uptake, under-vaccination with multiple dose, adolescent and adult vaccines, and inadequate resilience against large scale disruptions like the COVID-19 pandemic. Strategies addressing these challenges include education and awareness-based campaigns, mobile phone-based appointment reminders, financial incentives to service providers and vaccinees, as well as supportive supervision and performance monitoring programs for service providers. Geospatial, logistics, and systems models have been used as decision support to inform immunization strategies.

Conclusions: The review highlights challenges impeding vaccine access and uptake, casting concerns on the sustainability and resilience of immunization programs in sub-Saharan Africa. While improvement strategies have been employed, very few were based on human-centered design approaches for decision support. Employing systems thinking is recommended to reveal dynamic mechanisms and to design strategies for the long-term viability of immunization efforts.