Despite the growing body of literature on nanovaccines, focused analyses of platforms tested in and undergoing clinical investigation remain limited. This review addresses this gap by critically examining recent advancements and highlighting nanovaccine technologies that have undergone human clinical trials. Using an extensive search on clinicaltrials.org, we explored the diverse applications of nanovaccines, including leading SARS-CoV-2 candidates and platforms targeting other infectious diseases and cancers. We also highlighted foundational research that has enabled clinical investigation of nanovaccines over the past decade, highlighting their potential to address a range of medical conditions. While many technologies have been developed to combat SARS-CoV-2, several key innovations targeted a broader spectrum of diseases. This review details these technologies, focusing on their materials and mechanisms of action in inducing immune protection, while also exploring how nanomedicine facilitates nanovaccine development and introduces novel adjuvant concepts. Finally, we provided a retrospective analysis of the development journey of these platforms, offering insights into the intellectual and technological efforts behind their clinical translation. By bridging the gap between research and application, this review aims to give readers a comprehensive understanding of how nanovaccines progress from the laboratory to clinical practice.