RecruitingPhase 1Biological interventionA Safety and Immunogenicity Trial of OCU500, ChAd36 Vector Encoding SARS-CoV-2 Spike Vaccine Via Intranasal and Inhalational Routes in Previously Vaccinated AdultsThis phase 1 randomized, open-label, dose-escalation clinical trial evaluates the safety and immunogenicity of OCU500, a ChAd36 Vector Encoding SARS-CoV-2 Spike Vaccine, in healthy adults aged 18-64 who previously completed a primary COVID-19 vaccination series and at least one booster. The study evaluates two dose levels (1×10\^10 viral particles (VP) and 5×10\^10 VP) and two routes of administration (intranasal and inhaled). The trial includes 80 participants across four study arms (20 per arm). The primary objective is to evaluate the safety and reactogenicity of a single dose of OCU500 administered in previously vaccinated healthy adults.