CRISPR-Cas9: Genome Engineering and Future Vaccine Applications

The CRISPR-Cas9 system, a transformative genome engineering tool derived from prokaryotic adaptive immunity, is reshaping the landscape of biological research and therapeutic development. This review provides a critical synthesis of its rapidly evolving, yet underexplored, application in rational vaccine design. We analyze how CRISPR-Cas9 and its derivative platforms (including base editing, prime editing, and CRISPRi/a) are being repurposed from therapeutic gene editing to become indispensable assets in vaccinology. This transition is powered by the convergence of CRISPR-mediated precision with synthetic biology, enabling the rapid engineering of novel vaccine vectors and attenuated strains, the precise optimization of antigen sequences for enhanced breadth and potency, and the direct modulation of host immune responses. Notwithstanding this potential, significant technical and translational hurdles persist, including off-target editing risks, delivery inefficiencies in vivo, and unresolved regulatory pathways for genetically modified vaccines. We detail these mechanisms and evaluate the current preclinical and clinical landscape, while addressing persistent challenges in safety, delivery, and scalability. By delineating these advances and obstacles, this review outlines a forward-looking framework for leveraging CRISPR technology to create programmable, precision vaccines against emerging and re-emerging pathogens, moving the field beyond empirical methods toward a new paradigm of rational immunization.