Project Abstract This proposal outlines the scientific agenda for the COVID-19 Prevention Network (CoVPN) Vaccines Leadership Operations Center (LOC) for implementation of the COVID-19 vaccine efficacy trial entitled “A parallel-group, Phase III, multi-stage, modified double-blind, multi-armed study to assess the efficacy, safety, and immunogenicity of two SARS-CoV-2 Adjuvanted Recombinant Protein Vaccines (monovalent and bivalent) for prevention against COVID-19 in adults 18 years of age and older.” With the global COVID-19 pandemic, we recognize a significant need for vaccines that modify COVID-19 in SARS-CoV-2 infected individuals. Addressing this gap, the National Institutes of Health (NIH) led rapid constitution of the CoVPN, partnering 5 NIH supported clinical trial networks, to create an enhanced network of physician-scientists at 145 United States (US) and 71 international clinical trial sites in 17 countries dedicated to developing globally effective vaccines for SARS-CoV-2. Due to its extensive experience implementing global HIV vaccine trials over the last 20 years, the HIV Vaccine Trials Network (HVTN) LOC was selected as the LOC for CoVPN vaccine trials. This Phase 3, multi-stage, modified double-blind, placebo-controlled, multi-armed study will test the efficacy, safety and immunogenicity of Sanofi-Pasteur SARS-CoV2 prefusion Spike delta TM with AS03 adjuvant, monovalent D614 (monovalent vaccine) & SARS-CoV2 prefusion Spike delta TM with AS03 adjuvant, bivalent D614/B.1.351 (bivalent vaccine), to modify COVID-19 disease in adults 18 years of age and older. Participants will be recruited from clinical trial sites across the US and globally using data analytics to target high risk individuals with a diverse racial and ethnic profile. Participants will receive symptomatic screening for SARS-CoV-2 infection, and if they become infected will be monitored with frequent clinical check-ins and remote monitoring of vital signs. Infected individuals who progress to moderate-severe COVID-19 will be referred for hospitalization. All trial endpoint assays will be done using qualified and validated assays for diagnosis and immune monitoring. Specific aims of this study are to assess the clinical efficacy of the investigational CoV2 preS dTM recombinant protein adjuvanted with AS03 – both monovalent and bivalent (“study vaccines”) in naïve adults for the prevention of symptomatic COVID-19 occurring > 14 days after the second injection; to assess the safety of the study vaccines compared to placebo throughout the study; to assess, in participants who are SARS- CoV-2 naïve, the clinical efficacy of the CoV2 preS dTM-AS03 vaccines for prevention of the following occurring > 14 days after the second injection: prevention of SARS-CoV-2 infection, prevention of severe COVID-19; to describe the frequency & spectrum of disease in episodes of symptomatic COVID-19 in SARS-CoV-2 non-naïve adults in each study group. This efficacy trial will tell us much about the ability of two recombinant vaccines, targeting two of the most common SARS-CoV-2 variants, to induce strong adaptive protective responses. After the Novavax vaccine, this is the second large scale recombinant protein vaccine to be tested for efficacy and it is the first trial to use a bivalent vaccine including the B.1.351 variant of concern. If successful, this will be an important vaccine that can be scaled up rapidly and deployed throughout the world. The results of this trial will be used to assess registration of this vaccine product and will also provide crucial information to inform future generations of COVID-19 vaccines.

Project Narrative The outbreak of SARS-CoV-2 across the globe presents an unprecedented health risk to the world's population and requires intensive study of key gaps in our understanding of the immune response and what adaptations lead to protective immunity. In this study, the CoVPN will apply its laboratory, biostatistical and vaccine trial leadership expertise to assess this response in approximately 30,000 persons at clinical trial sites across the globe. The goal of this protocol is to rapidly assess the efficacy of two recombinant protein CoV2 preS dTM adjuvanted to AS03 vaccines (D614 (monovalent) & D614 + B.1.351 (bivalent)) to prevent SARS-CoV-2 infection and/or modify the severity of COVID-19 disease in SARS-CoV-2 infected individuals.