Navigating the Road to Immunization Equity: Systematic Review of Challenges in Introducing New Vaccines into Sub-Saharan Africa's Health Systems.

Over the past 50 years, developing new vaccines has been pivotal in responding to emerging and re-emerging diseases globally. However, despite substantial partner support, introducing new vaccines in sub-Saharan Africa remains challenging. This systematic review documents the barriers to new vaccine introduction in sub-Saharan Africa by distinguishing between vaccines integrated into routine immunization programs and those introduced primarily for outbreak response. A comprehensive electronic search was conducted across five databases for articles published in English or French on the challenges of new vaccine introduction in sub-Saharan Africa. Three reviewers screened articles independently based on the titles and abstracts, with full-text assessments conducted for inclusion. Data were analyzed thematically and synthesized narratively. A total of 796 articles were retrieved from the five databases. Following the screening, 33 articles were finally retained and included in the review. These articles concerned the introduction of eight new vaccines (malaria vaccine, COVID-19 vaccine, HPV vaccine, Ebola vaccine, cholera vaccine, hepatitis B vaccine, rotavirus vaccine, and typhoid vaccine). The analyses revealed coordination and financing challenges for six vaccines in seventeen countries, acceptability challenges for five vaccines in ten countries, logistical challenges for two vaccines in six countries, and quality service delivery challenges for three vaccines in thirteen countries. Addressing the challenges of introducing new vaccines in sub-Saharan Africa requires targeted, evidence-based strategies. Prioritizing political commitment, innovative funding, public education, workforce development, and infrastructure improvements will strengthen immunization systems and enable timely vaccine delivery. Collaborative efforts and a focus on local context can advance equitable health outcomes, safeguard public health, and support global immunization goals.