hAd5-S-Fusion

hAd5-S-Fusion is a recombinant viral vector vaccine candidate against COVID-19 that uses a human adenovirus serotype 5 (hAd5) platform engineered to deliver the SARS-CoV-2 spike (S) protein in a modified form that enhances cell-surface expression and immunogenicity[2][3][4]. The vaccine is part of a family of constructs (with and without the addition of nucleocapsid protein expression) and is specifically designed to elicit strong T-cell and antibody (humoral) immune responses[2][3][4]. It has been studied as a single-antigen (S-Fusion only) and dual-antigen (S-Fusion + N-ETSD) vaccine, with the S-Fusion component being key to enhanced immune activation compared to wild-type S alone[2]. hAd5-S-Fusion and related vaccines are developed by ImmunityBio primarily for the prevention and potential treatment of COVID-19, and are administered via subcutaneous, intranasal, or oral (capsule) routes[2][3]. The platform is notable for its use of a next-generation hAd5 vector designed to overcome pre-existing adenovirus immunity in the population, enabling both primary vaccination and boosting[3]. The S-Fusion modification results in improved display of the receptor-binding domain (RBD) of the spike protein, promoting neutralizing antibody production and robust T cell responses[2].