• NAMs shift vaccine testing from animal models to human-relevant in-vitro methodologies • Framework integrates NAMs at key development stages of vaccine for regulatory use • Addresses technical challenges in NAMs implementation for vaccines safety • Strategic transition reduces animal use before complete replacement • NAMs improve human predictivity while supporting 3Rs principles This 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.
Srinivasan et al. (Sun,) studied this question.