Study to Assess Safety, Reactogenicity and Immunogenicity of the VACCINE RNA MCTI CIMATEC HDT (HDT-301) Vaccine Against COVID-19

Inclusion Criteria: Participants must meet ALL of the following criteria to be eligible for inclusion in this phase I study. i. Men and women ≥ 18 years to ≤ 55 years of age; ii. Must be generally healthy as confirmed by a medical history and physical examination for study entry; iii. Subjects who have not been previously immunized with any SARS-CoV-2 vaccine OR subjects who have been immunized with SARS-CoV-2 vaccine based inactivated virus technology at least 3 months from the administration of the second dose and have neutralizing antibody titers less than or equal to 40% in plasma samples tested at 1:40 dilution; iv. Women of childbearing age and of childbearing potential must present during the screening period and on the day of each vaccination the result of a pregnancy test (serum test) with a negative result, as well as not be breastfeeding; in addition, to enroll in the study as volunteers, women who have sex with men must necessarily use one of the contraceptive methods listed below at the time of enrollment and up to 60 days after the last injection of the vaccine (this 60-day interval has been defined as a safety criterion): hormonal (e.g., oral, transdermal, intravaginal, implant, or injection); double barrier (i.e., condom, diaphragm, or cervical cap with spermicide); intrauterine device (IUD) or intrauterine system (IUS); vasectomized (6 months minimum) or abstinent partner; bilateral tubal ligation (if no conception post-procedure); tubal occlusion or bilateral salpingectomy. These precautions are necessary because of unknown effects that Vaccine RNA MCTI CIMATEC HDT may cause in a fetus or newborn. Women will be considered out of the potential to become pregnant if they are postmenopausal (defined as spontaneous amenorrhea of at least 12 months and confirmed with follicle-stimulating hormone concentrations \>40 mUI/ml) or have documented hysterectomy and/or oophorectomy; and, non-sterile men who agree to use adequate contraception with their partner during and up to 60 days after the last injection of the study vaccine; v. The following laboratory test values for screening must be within normal limits or not clinically significant, as determined by the Researcher and approved by the Medical Monitor: sodium, potassium, Glutamic-Oxalacetic Transaminase (GOT), Glutamic-Pyruvic Transaminase (GPT), total bilirubin, alkaline phosphatase, creatinine, fasting glucose, total WBC, hemoglobin, and platelet count. Abnormal results may be repeated once for confirmation at the discretion of the Researcher; vi. The following serological tests must be negative: HIV 1/2 antibody, hepatitis B surface antigen (HBsAg) and hepatitis C virus (HCV) antibody; vii. Negative test for recreational drugs and alcohol according to the standards of the Clinical Research Unit; viii. Normal or not clinically significant urine test as determined by the clinician or designee. Abnormal results may be repeated at the discretion of the Researcher; ix. Must present blood count within normal limits up to 10 days prior to administration of the first dose of the Vaccine RNA MCTI CIMATEC HDT; x. Must present negative RT-PCR test for SARS-CoV-2 24 to 48 h before administration of the study vaccine and absence of signs and symptoms compatible with COVID-19 (e.g. fever, cough, shortness of breath, chills, etc.); xi. Must be able to complete the Mnemonic Adverse Event Questionnaire (MMEA) (Appendix 1); xii. Must give informed consent, be able and willing to make all evaluation visits, be accessible by phone or personal contact by the local study team, and have a permanent address. Exclusion Criteria: Individuals who meet ANY of the following criteria below will be excluded from the study (ineligible). i. Participation in another experimental protocol and/or receipt of any investigational product within the last 3 months prior to screening; ii. Individuals infected with SARS-CoV-2 confirmed by RT-PCR; iii. Treatment with immunosuppressive drugs (e.g., oral or injectable steroidal anti-inflammatory drugs, such as prednisone, or high-dose inhalation) or cytotoxic therapies (e.g., chemotherapeutic drugs or radiation) within the last 6 months prior to screening; iv. Individuals who have received transfusion of blood, plasma, or immunoglobulins in the last 3 months prior to screening; v. Donation of blood products (platelets, whole blood, plasma, etc.) in the last month before screening (1 month before screening); vi. Received any vaccinations in the last month before screening or have any immunizations planned during the study, with the exception of seasonal influenza vaccine, which can be given after 30 days after the second injection of the study; vii. Individuals who have been immunized with any vaccine for SARS-CoV-2 at any time who have neutralizing antibody titers greater than 40% in plasma samples tested at 1:40 dilution; viii. History of autoimmune disease or other causes of immunosuppressive states; ix. History of any other acute or chronic disease (including cardiovascular, pulmonary, neurological, hepatic, rheumatic, hematological, metabolic or renal disorders, uncontrolled hypertension) or use of medications that, in the opinion of the Principal Investigator, may interfere with the safety or immunogenicity evaluation of the vaccine; x. Skin rash, tattoos or any other dermatological condition that may adversely affect the vaccine injection site or interfere with its evaluation; xi. BMI ≥ 32; xii. Hypertension (systolic \> 150 or diastolic \> 95); xiii. History of significant psychiatric illness with current medication use; xiv. Known or suspected alcohol or drug abuse in the last 6 months prior to screening; xv. Chronic tobacco user (\> 20 packs/year); xvi. Individuals with a history of prior anaphylaxis or severe allergic reaction to unknown vaccines or allergens; xvii. Individuals unlikely to cooperate with the requirements of the study protocol.