Inclusion Criteria:  Adults 18 or older at the time of consent; Agree to periodic contacts by telephone, electronic means and home visits; Be healthy (absence of clinically significant medical condition, acute or chronic, provided by medical history, physical examination and clinical assessment of the investigator); Present Body Mass Index (BMI from 17 to 40 Kg/m² inclusive) at the time of screening;  Demonstrate intention to participate of the study, documented by the participant's signing the Informed Consent Form.  For participants from Step A and from groups B1a, B1e, C1a from Alternative 1 or from groups B2a, and C2a from Alternative 2  Age under 60 years at the time of the first vaccination; Not being among the vaccination groups proposed by the National Immunization Program as priorities; Have negative result for antibody test against SARS-CoV-2 by CLIA performed within 7 days before study immunization; No history of COVID-19 diagnosed by RT-PCR or by antigen test;  No history of vaccination against COVID-19  For SARS-CoV-2 natural exposure group participants from Alternative 1 Groups B1c and C1b or Alternative 2 Group C2c  Have positive result for antibody test against SARS-CoV-2 by CLIA performed in the study laboratory; No history of vaccination against COVID-19; For participants in the pre-vaccination group of Groups B1d and C1c of Alternative 1 or Group C2d of Alternative 2 Have a history of vaccination with two doses of inactivated vaccine against COVID-19 14 to 28 days apart with a schedule started 26 weeks or more; Not having a history of COVID-19 diagnosed by RT-PCR or by antigen test after the first vaccination; Be between 18 and 59 years old or 60 years old or more at the time of initiation of vaccination, depending on the age group corresponding to the group  Exclusion Criteria:  Use of any investigational product within 90 days prior to randomization or planning to use a product during the period of participation in the study; Have received a vaccine in the last 28 days prior to participant study inclusion or yet having an immunization programmed during the study period; Evidence of uncontrolled neurological, cardiac, pulmonary, hepatic or renal disease, according to anamnesis or physical examination. Significant changes in treatment or hospitalizations due to worsening of the condition in the last three months are indicators of uncontrolled disease; History of severe allergic reaction or anaphylaxis to the vaccine or vaccine components of the study; Allergy history to egg or chicken; History of angioedema or anaphylactic reaction; Suspected or confirmed fever within 72 hours prior to vaccination or axillary temperature superior than 37.8 ° C * on the vaccination day (inclusion may be postponed until the participant completes 72 hours without fever); Vital signs altered, clinically relevant in the opinion of the principal investigator Neoplasm diseases (except basal cell carcinoma and cervical carcinoma in situ), Suspected or confirmed diseases with compromised immune system including: congenital or acquired immunodeficiencies and uncontrolled autoimmune diseases according to anamnesis or physical examination. Significant changes in treatment or hospitalizations due to worsening of the condition in the last three months are indicators of uncontrolled disease; Use of immunosuppressive therapies six months prior to inclusion in the study or its scheduled use in subsequent two years of inclusion. The dose of corticosteroids considered immunosuppressive is equivalent to prednisone at a dose of 20 mg/day for adults (in the protocol it is ≥0.5 mg/kg/day), for more than one week. The continuous use of topical or nasal corticosteroids is not considered immunosuppressive. Immunosuppressive therapies will be considered: antineoplastic chemotherapy, radiotherapy, immunosuppressants to induce tolerance to transplants, among others. Have received hemoderivatives (transfusions or immunoglobulins) in the last three months before inclusion in the study, or scheduled administration of hemoderivatives or immunoglobulin in subsequent two years of study inclusion; History of bleeding disorders (for example, deficiency of clotting factors, coagulopathy, platelet dysfunction), or previous history of significant bleeding or bruising after IM injection or venipuncture; Any use considered to be alcohol or drug abuse in the last 12 months prior to study inclusion that has caused medical, professional or family problems, as indicated by clinical history Behavioral, cognitive or psychiatric illness that, in the opinion of the principal investigator or his/her medical representative, affects the participant's ability to understand and collaborate with the study protocol requirements; The participant is a member of the team that is conducting the study or is in a dependent relationship with one of the study team members. Dependency relationships include close relatives (ie, children, partner / spouse, siblings, parents), as well as employees or students who are directly dependent on the Researcher or site staff that is conducting the study;  Any other condition that, in the opinion of the principal investigator or his/her medical representative, could jeopardize the safety or rights of a potential participant or that would prevent him/her from complying with this protocol.  To StageA:  Abnormalities in laboratory screening tests considered to be excluding in the principal investigator opinion or his/her medical representative. Grade 1 changes are considered to be insignificant, unless the principal investigator or his/her medical representative indicates otherwise. If any change in the tests is due to a reason considered temporary, the tests may be repeated up to three times during the screening period;  Positive serological tests for the human immunodeficiency virus (Ac HIV1/2); Hepatitis B (HbSAg or Anti-HBc) or Hepatitis C (Ac HCV);  For female:  Pregnancy (confirmed by positive β-hCG test), breastfeeding and/or expressing an intention to have sexual practices with reproductive potential without using a contraceptive method in the subsequent three months to vaccination.  The temperature measured with a skin thermometer using a temporal scanner is considered equivalent to the axillary temperature.