A Study Looking at the Effectiveness, Immune Response, and Safety of a COVID-19 Vaccine in Adults in the United Kingdom

This is a study to evaluate the efficacy, immune response, and safety of a coronavirus disease 2019 (COVID-19) vaccine called SARS-CoV-2 rS with Matrix-M1 adjuvant in adults aged 18-84 years in the United Kingdom. A vaccine causes the body to have an immune response that may help prevent the infection or reduce the severity of symptoms. An adjuvant is something that can make a vaccine work better. This study will look at the protective effect, body's immune response, and safety of SARS-CoV-2 rS with Matrix-M1 adjuvant in the study population. Participants in the study will randomly be assigned to receive SARS-CoV-2 rS with Matrix-M1 adjuvant or placebo. Each participant in the study will receive a total of 2 intramuscular injections over the course of the study. Approximately 15,000 participants will take part in the study. The first approximately 400 participants who meet additional criteria will receive a flu vaccine, in addition to the SARS-CoV-2 rS vaccine or placebo, as part of a sub-study. An effort will be made to enroll a target of at least 25% of participants who are ≥ 65 years of age, as well as prioritizing other groups that are most affected by COVID-19, including racial and ethnic minorities. Unblinding of treatment assignment may occur in order to allow a participant to make an informed decision regarding receipt of an already approved or deployed SARS-CoV-2 vaccine. Participants who choose to receive an approved or deployed SARS-CoV-2 vaccine as per UK government guidance will be encouraged to remain in the study for scheduled safety assessments.