The phase 1/2 clinical studies evaluating the safety and immunogenicity of the heterologous rAd26 and rAd5 vector-based COVID-19 vaccine reported outcomes across several key areas. These primary results included the evaluation of adverse effects, the cell-mediated (T-cell) immune response to the SARS-CoV-2 glycoprotein, the humoral immune response encompassing RBD-specific IgG and neutralizing antibodies, and the specific neutralizing antibody response to the rAd26 and rAd5 viral vectors.