Vaccine and Treatment Evaluation Units - DMID 21-0012

Summary/Abstract The Emory VTEU will participate in DMID 21-0012, A Phase 1/2 Study of Delayed Heterologous SARS-CoV-2 Vaccine Dosing (Boost) after Receipt of EUA Vaccines. Knowledge of the safety, tolerability, and immunogenicity of SARS-CoV-2 delayed homologous and heterologous boost vaccine incorporating a similar or variant spike administered following EUA dosing regimens might induce immunity to variant circulating strains and improve upon breadth and durability of protection. Utilizing the EUA-dosed COVID-19 vaccines available (currently mRNA-1273, mRNA- BNT162b2, and AD26.COV2.S), we propose to evaluate innate, cellular, and humoral immune responses elicited from multiple prime boost combinations, utilizing the mRNA with homologous spike protein as a boost while seeking to avoid duplicating trial designs currently in planning stages or in process. This phase 1/2 study will evaluate the safety, tolerability, and immunogenicity of delayed homologous or heterologous boost SARS-CoV-2 vaccines in two cohorts of healthy adult participants, one of which has received EUA vaccinations and one of which is vaccine-naïve. We will follow these participants for 12 months following receipt of the delayed boost. In addition to screening and vaccination visits, study visits will occur at 2 weeks, 1, 3, 6, and 12 months post-vaccination with blood collection for immunogenicity assessments. Solicited adverse events (AEs) will be collected using a memory aid and recorded on the appropriate DCF from the time of each vaccination through 7 days post each vaccination. Unsolicited AEs will be collected through 28 days post each vaccination. And after 28 days post last vaccination through the end of study, only SAEs, Protocol Specified adverse events of special interest (AESIs), medically attended adverse events (MAAEs), and new-onset medical conditions (NOCMCs) will be reported as AEs. The study will be conducted across the two Emory VTEU sites: Emory Children's Center (ECC-VRC) and Hope Clinic. Recruitment and enrollment will occur at both sites. The Emory VTEU has proven essential in the fight against the pandemic. This supplement will allow for further investigations into vaccines trials studying vaccine dosing boosts. 1