This is a first time in human (FTiH) study designed to explore the safety, tolerability, and immunogenicity of COVIDITY in healthy adults when administered by needle-free injection.~COVIDITY consists of two DNA plasmid vaccines (SCOV1 and SCOV2). SCOV1 is expected to be active against the original SARS-CoV-2 strain and the B.1.1.7 (Alpha) variant, and to a slightly lesser extent against the B.1.351 (Beta) and P.1 (Gamma) variants. SCOV2 is expected to boost the effects of SCOV1 while providing further enhanced protection against the B.1.351 (Beta) and P.1 (Gamma) variants. Antibodies induced by SCOV1 and SCOV2 also show strong binding to the B.1.617.2 (Delta) and B.1.1.529 (Omicron) variants in nonclinical models.~When the study commenced in 2021 there were significant numbers of unvaccinated individuals who also had no known exposure to SARS-CoV-2; however as the epidemiology rapidly changed with most people having either been vaccinated, or infected with SARS-CoV-2, or both, the use of SCOV2 only in these populations made rational sense, particularly as it has more mutations in common with the Omicron variant. A protocol amendment submitted in February 2022, permitted the enrolment of participants irrespective of their previous COVID-19 vaccination and/or SARS-CoV-2 infection status, amended the treatment regimen to SCOV2 only, and aligned the administered dose with the doses employed for other DNA vaccines. Immunogenicity analyses will be performed separately for the vaccine-naïve, previously vaccinated and previously infected immunogenicity analysis populations.~Eligible participants will be randomised 1:1 to be vaccinated by either IM or ID needle-free injection in blocks determined by their previous COVID-19 vaccination and SARS-CoV-2 infection status, as follows:~Participants enrolled under the initial protocol (Amendment 1): Two doses of SCOV1 (administered on Day 1 and Day 29), followed by two doses of SCOV2 (not before Days 113 and 141 [doses 4 weeks apart]). A final end of study assessment will then be performed 6 weeks after last dose of study vaccine (Day 183).~Participants enrolled under protocol Amendment 2: Vaccine Naive and Previously Vaccinated participants: Two doses of SCOV2 (administered on Day 1 and Day 29) with a final end of study assessment performed 6 weeks after last dose of study vaccine (Day 71); Previously Infected participants: A single dose of SCOV2 (administered on Day 1) with a final end of study assessment performed 6 weeks after last dose of study vaccine (Day 43)~Each dose of SCOV1 and/or SCOV2 will be administered via needle-free injection, either intradermally (study Arm 1; PharmaJet Tropis® device) or intramuscularly (study Arm 2; PharmaJet Stratis® device). Eligible injection sites include the outer aspect of the upper left or right arm (medial deltoid muscle) or the left or right outer thigh (lateralis muscle).~This study is expected to enrol up to 80 participants at a single centre in South Africa. Enrolment will attempt to continue until at least 10 evaluable participants receive all protocol-required SCOV2 vaccinations for each immunogenicity analysis population. However, should the epidemiology be such that certain populations cannot be enrolled, the Safety Review Committee may determine that enrolment for that population be considered complete.
The main objectives of this study are to assess the safety, tolerability and immunogenicity of the candidate SARS-CoV-2 vaccine, COVIDITY, when administered using a needle-free ID or IM injection device.