ABNCoV2 Vaccine in SARS-CoV-2 (COVID-19) Seronegative and Seropositive Adult Subjects

For this Phase 2 trial ABNCoV2-01, in a run in phase 6 adults (comprising of 3 subjects in each Group 1 and 2) will be vaccinated at 1 clinical trial site in a consecutive manner, with an at least 48 hours interval between the first and second subject of each group, then the second and third subject dosed on consecutive days, before opening up to full enrolment of the trial. Safety assessments will be based on solicited and unsolicited adverse event (AE) data (first week after vaccination) evaluated by an independent Data Monitoring Committee (DMC). After a positive DMC recommendation, enrolment to the rest of Group 1 and 2 of the trial will commence. Group 3 subjects will be enrolled after completion of Group 2 enrollment. This phase 2 trial will evaluate a homologous prime-boost regimen with 100 µg ABNCoV2 in initially seronegative adult subjects (Group 1), as determined by a qualitative test for SARS-CoV-2 antibodies, compared to a single boost vaccination with 100 µg (Group 2) and 50 µg (Group 3) ABNCoV2 in initially seropositive subjects, as defined by a positive qualitative test for SARS-CoV-2 antibodies and either a history of SARS-CoV-2 vaccination or previous COVID-19 disease (Group 2 and 3) at least 90 days prior to planned trial vaccination. Due to the timing of the addition of Group 3, enrollment into Group 2 will be completed prior to enrolling subjects into Group 3. Therefore, no randomization will be required for the seropositive subjects.