02520nas a2200229   4500000000100000008004100001260001500042653001800057653001900075653002700094653003100121653003000152653001100182100002500193700001600218245007700234856007200311300001100383490000600394520187600400022001402276       2026                            d  c2026-01-0110a3Rs principle10aContext-of-use10aHuman relevant testing10anew approach methodologies10aVaccine safety assessment10amodels1 aRajamuthu Srinivasan1 aPaul Desert00aNew approach methodologies in non-clinical safety assessment of vaccines  uhttps://www.sciencedirect.com/science/article/pii/S3050620426000126  a1000870 v23 aThis review focuses on the application of New Approach Methodologies (NAMs) in vaccine development. While animal testing remains the current gold standard, its limited human predictivity and ethical concerns have accelerated the development of NAMs as complementary and potentially alternative approaches. These methodologies encompass a broad spectrum of tools — including in vitro assays, in silico models, omics technologies, microphysiological systems, and computational approaches—integrated with clinical observations to enhance understanding of adverse outcome pathways. Although the transition from animal testing to NAMs promises improved human relevance and adherence to the 3Rs principle—replacement, reduction, refinement—the vaccine industry faces significant regulatory, scientific, and organizational challenges through this transformative journey. Regulatory agencies, including the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA), have established platforms and frameworks to facilitate NAMs integration, and the European Commission is preparing a formal roadmap targeting the complete phase-out of animal testing where scientifically justified. This review details organizational frameworks and NAMs implementation and explores approaches for harmonized adoption across the vaccine industry and regulatory bodies globally. It highlights how NAMs can be positioned at critical stages of vaccine development, from early safety assessment to mechanistic investigations. With regulatory bodies encouraging NAMs adoption, we recommend a sequential transition: first reducing animal usage through NAMs-supported accelerated approaches, then progressing towards complete replacement. This strategic implementation could revolutionize vaccine safety assessment while ensuring scientific integrity and regulatory validation.  a3050-6204