This is a Phase 3 study (efficacy study) of two experimental vaccines against SARS-CoV-2. The full names are:

1. Monovalent: SARS-CoV2 prefusion Spike delta TM with AS03 adjuvant, monovalent D614 (CoV2 preS dTMAS03 [D614])

2. Bivalent: SARS-CoV2 prefusion Spike delta TM with AS03 adjuvant, bivalent D614/B.1.351 (CoV2 preS dTM-AS03 [D614 + B.1.351])

This study is also known as “VAT00008” or “CoVPN 3005.”

The study vaccine is developed by Sanofi Pasteur, a company that produces vaccines against other diseases such as diphtheria, tetanus, pertussis, meningitis and influenza.

The vaccine will be manufactured using the same technology as is used to make an influenza vaccine that is licensed in the US for the prevention of influenza in adults, marketed as Flublok®.

The study will enroll about 37,500 participants globally.

The purpose of the study is to learn if:

• The study vaccines can prevent symptomatic COVID-19 illness
• The vaccines are safe The vaccines make people too uncomfortable
• The study vaccines can prevent infection with SARS-CoV-2
• The study vaccines can prevent severe COVID-19 illness and hospitalization

Background

SARS-CoV-2 is a novel coronavirus that emerged in the human population and has led to a pandemic of acute respiratory disease named COVID-19. The burden of SARS-CoV-2 morbidity and mortality has been catastrophic with greater than 2.8 million deaths recorded since first emerging in December 2019 among over 131.9 million confirmed cases (as of 06 April 2021) (2). In many locations, the rapid emergence of COVID-19 has overwhelmed the capacity of health systems to provide care for COVID-19-affected patients, let alone unaffected patients. Interventions to reduce transmission through reduction of population contact (also called social distancing) has had profound economic consequences. Safe and effective vaccines with sufficient supply would be vital to address the significant medical and societal burden caused by the pandemic. The CoV2 preS dTM-AS03 vaccines developed by Sanofi Pasteur utilize a recombinant protein approach in combination with an oil-in-water adjuvant, AS03 provided by GlaxoSmithKline (GSK). The CoV2 preS dTM-AS03 vaccines belong to the pharmacotherapeutic group of “covid19 vaccines”. The vaccines contain recombinant S protein, stabilized to maintain native prefusion trimer configuration as present on the viral envelope. The purpose of the study is to assess the efficacy, safety, and immunogenicity of two CoV2 preS dTM-AS03 vaccines (monovalent and bivalent) in adults 18 years of age and older in a multi-stage approach.

Methods

This study is designed to maximize representation of the broader population by minimizing exclusionary eligibility criteria and allowing the participation of individuals with a broad range of medical conditions, including controlled HIV infection, Hepatitis B and Hepatitis C, and conditions associated with an increased risk of severe COVID-19. It is also designed to be inclusive of other subpopulations affected by COVID-19, including older adults as well as ethnic and racial minorities. Participants will be screened for eligibility criteria at the time of inclusion and then randomized to either the investigational vaccine or placebo in a 1:1 ratio in each stage. • Stage 1: eligible participants will be randomized to receive either 2 injections of CoV2 preS dTM-AS03 (D614) vaccine or Placebo 1 (participants who receive the placebo as part of Stage 1) administered 21 days apart • Stage 2: eligible participants will be randomized to receive 2 injections of either CoV2 preS dTM-AS03 (D614 + B.1.351) vaccine or Placebo 2 (participants who receive placebo as part of Stage 2) administered 21 days apart. Randomization will be stratified by age groups (18-59 years of age and 60 years of age and older), baseline SARS-CoV-2 rapid serodiagnostic test positivity, and site. In the event that the enrollment in Stage 1 overlaps with enrollment of Stage 2, participants will continue to be randomly allocated to one of the investigational vaccine groups and their matched placebo group in a 1:1 ratio. Approximately 37 430 participants are planned to be enrolled (8000 per study intervention group in Stage 1 and 10 715 per study intervention group in Stage 2)The duration of the study for each participant will be 365 days post-last injection (ie, approximately 386 days total). The study includes 8 visits at D01, D22, D43, D78, D134, D202, D292, and D387. Participants will be contacted once a week over the entire duration of the study to inquire about the development of symptoms of COVID-19-like-illness and to remind participants to contact study staff if they experience symptoms of COVID-19-like illness. Additional visits and procedures are included for participants with verified COVID-19-like illness.