Inclusion Criteria:  Adults with age 18 to 50 years. Willingness. For married females of childbearing age: Willingness to practice continuous effective contraception for one year from the start of the study. Agreement to refrain from blood donation during the study. Body temperature is within the normal range (36.5 - 37.5°C). General good health as established by medical history, physical and laboratory examinations.  Exclusion Criteria:  Pregnancy or lactation. Inability to provide informed consent. Recent receipt of any vaccination within 30 days prior to baseline. Planning to receive any vaccination during the course of the study. Prior receipt of Adenovirus vaccine, or any other Coronavirus vaccine. Recent receipt of any immunoglobulin within 90 days prior to baseline. Recent receipt of any blood product within 90 days prior to baseline.  Volunteers who are immunosuppressed or receiving immunosuppressive medications, including:  HIV infection, asplenia, recurrent severe infections, and the use of immunosuppressive medications within the past 6 months, except for topical steroids or short-term oral steroids (course lasting < 14 days).  Currently taking any product (investigational or off-label) for prevention of COVID-19 disease. Having any autoimmune disease. History of allergic reactions for any of the vaccine components. History of angioedema. History of anaphylaxis. History of cancer. History of serious psychiatric conditions that are likely to affect participation in the study. Having bleeding disorders. Having chronic respiratory diseases. Having chronic cardiovascular disease, gastrointestinal disease, liver disease, renal disease, endocrine disorders, and neurological illness. Volunteers with BMI ≥ 40 Kg/m2 or ≤ 18 Kg/m2. Current alcohol abuse. Drug abuse within 5 years prior to baseline. History of laboratory-confirmed COVID-19 or seropositivity for SARS-CoV-2 or positive serum immunoglobulin M (IgM) and immunoglobulin G (IgG) to the SARS CoV-2 or abnormal chest CT-Scan (COVID-19 image) or positive pharyngeal/sputum swabs for SARS-CoV-2. Participation in other studies involving study intervention within 28 days prior to study entry and/or during study participation. High-risk population (volunteers who work in front-line health facilities or were in close contact with confirmed COVID-19 cases). Living in the same household as anyone at high risk of severe COVID-19. Any condition, according to the judgment of the investigator, that would interfere with the subject's ability to comply with all study requirements or that would place the subject at unacceptable risk by his/her participation in the study or impair the interpretation of the study data.