Bridging innovation and policy: comparative pathways of national vaccine development in low- and middle-income countries.

Objectives: To examine how national innovation and policy configurations enabled vaccine development in Brazil, Cuba, India, and Iran, and to distil lessons for low- and middle-income country (LMIC) vaccine sovereignty.

Methods: Narrative review of peer-reviewed and grey literature (2020-2023), guided by a structured search and screening approach; synthesis mapped to national and sectoral innovation system perspectives and technology readiness levels.

Results: Cuba and Iran leveraged mission-oriented public research and development (R&D) and domestic platforms; India combined indigenous R&D with large-scale licensed manufacturing; Brazil's scientific capacity was constrained by fragmented governance and supply-chain dependence. Adaptive regulation (e.g., emergency use authorization/conditional approvals), targeted technology transfer, and South-South partnerships accelerated progress but raised longer-term questions about intellectual property (IP) control and economic sustainability.

Conclusion: Institutional coherence, strategic IP management, and regional manufacturing alliances are as critical as scientific capacity for LMIC vaccine self-reliance. Policy priorities include pre-negotiated tech-transfer frameworks, regulatory preparedness, and investment in public R&D linked to distributed manufacturing.