The trial is part of Operation Warp Speed (OWS) and is being funded by Johnson & Johnson (a Janssen company); the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH); and the Biomedical Advanced Research and Development Authority (BARDA), a U.S. federal health agency.

The study will enroll up to 60,000 volunteers at nearly 215 clinical research sites in the U.S. and internationally. The trial sites are part of an NIAID-supported COVID-19 Prevention Network.

The Accelerating COVID-19 Therapeutic Interventions and Vaccines public-private partnership will ensure the protocols of all NIH- and OWS-supported phase III trials of investigational vaccines use the same assays and enables transparent evaluation of vaccines across trials.

Johnson & Johnson's vaccine candidate is a recombinant vector vaccine that uses human adenovirus to express the SARS-CoV-2 spike protein in cells. Preclinical data demonstrated that the vaccine induced neutralizing antibody responses in rhesus macaques and provided complete or near-complete protection against the virus in the lungs and nose. Interim results from an ongoing phase I/IIA trial in the U.S. and Belgium indicate that the vaccine has a positive safety profile and immunogenicity after a single vaccination.