Microneedle-based Rabies Vaccination: A Promising Approach Toward the WHO “Zero by ۳۰” Target

Introduction: Rabies remains a fatal zoonotic disease causing tens of thousands of deaths annually, predominantly in resource-limited countries, where intramuscular (IM) vaccines are limited by cost, cold-chain needs, and the need for skilled administration. Achieving the World Health Organization’s “Zero by ۳۰” target necessitates innovative, scalable, and cost-effective vaccine delivery approaches. In this study, we developed dissolving microneedle (MN) patches (dMNPs) loaded with rabies vaccine using hyaluronic acid (HA) and polyvinylpyrrolidone (PVP) as biocompatible and biodegradable polymers. Materials & Methods: An aluminum master mold fabricated by CNC machining contained ۴۰۰ cubical-pyramidal MNs (۸۰۰ µm height, ۳۰۰×۳۰۰ µm base), while PDMS replicas enabled precise two-step centrifugal casting. Morphology, virion integrity, mechanical strength, and ex vivo skin penetration were evaluated. Bagg Albino/subline C (BALB/c) mice received two doses of vaccine-loaded microneedles, IM injection, or blank patches, and virus-neutralizing antibodies were measured. Results: MNs exhibited uniform geometry (۶۵۱.۲±۴.۳ μm height), high mechanical strength (۰.۴۰۳±۰.۰۰۶ N/needle), and reliable skin penetration (~۳۰۰ μm). Transmission electron microscopy confirmed that rabies virions retained their bullet-shaped morphology after encapsulation and storage. Rabies virus-neutralizing antibodies showed comparable titers four weeks post-booster: dMNP (۱ mg; geometric mean titers (GMTs): ۷.۶۷ IU/mL, ۹۵% CI, ۶.۸%, ۸.۶۴%) versus IM (۱۰ mg; GMT: ۶.۹۵ IU/mL, ۹۵% CI, ۶.۲%, ۷.۸%; P>۰.۰۵), both surpassing protective thresholds (≥۰.۵ IU/mL), while controls remained seronegative. Conclusion: Beyond achieving robust immune responses, these dMNPs provide dose-sparing, thermostability, self-administration, and sharps-free delivery—which enhance feasibility, acceptance, and scalability, aligning with the WHO’s “Zero by ۳۰” target. This platform offers translational potential for equitable rabies prophylaxis in resource-limited settings.

کلیدواژه ها:

Microneedle ، Post-exposure prophylaxis (PEP) ، Rabies ، Rabies vaccine ، Vaccination