The first phase of the trial includes a cohort of healthy volunteers between the ages of 18 and 55. This phase is now advancing to include healthy subjects between the ages of 65 and 85; its phase II/III will explore effective vaccine dose. The vaccine is based on a proprietary replication-defective simian adenoviral vector that encodes the full-length coronavirus spike protein, according to the firm.

The GRAd vector belongs to species C adenovirus that are considered the most potent vaccine carriers and has low seroprevalence in humans. This means that GRAd vaccine immunogenicity is not affected by preexisting anti-human adenovirus antibodies.

ReiThera designed the study in collaboration with the Lazzaro Spallanzani National Institute for Infectious Diseases (INMI) in Rome, Italy; it has been financially supported by the Italian Ministry of Scientific Research, also in Rome and is being conducted at the institute and the GB Rossi University Hospital in Verona.