Phase 1, safety, immunogenicity and dose finding for two strengths of 0.5 × 10^6 and 2.5 × 10^6 (TCID50) inactivated SARS-CoV-2 vaccine FAKHRAVAC (MIVAC) injected in two schedules of two doses, 2 and 3 weeks apart in healthy adults aged 18-55 years: a randomized, double blind, placebo controlled, clinical trial

Inclusion criteria:

Iranian citizenship, and residing at a distance of 40-50 km from the study center The ability of participants to study and understand informed consent, preferably educational level of high school and higher Age between 18 and 55 years Body mass index between 18 and 35 kg/m2 Being healthy based on clinical and laboratory examinations Temperature less than or equal to 37.2°C sublingually measured by an electronic thermometer Negative IgG and IgM antibody titers against COVID-19 N antigen Negative RT-PCR test for COVID-19 Negative ELISA test for anti-HIV IgG Heart rate between 60 and 100 Systolic blood pressure between 90 and 140 mm Hg, diastolic blood pressure between 60 and 90 mm Hg Signing informed consent Accepting commitments to reduce the risk of COVID-19 infection in daily life Not pregnant Negative β-hCG pregnancy test on the screening and vaccination days The use of at least one safe method of contraception (condoms, oral contraceptive pills, IUD, Norplant capsule) for women of reproductive age 18 to 49 years Willingness to continue using at least one safe method of contraception (condoms, oral contraceptive pills, IUD, Norplant capsule) for women of reproductive age 18 to 49 years up to three months after the second vaccine dose Participants in the clinical trial should refrain from donating blood or plasma from the time of the first vaccine dose until three months after the second vaccine dose should not participate in another trial during the study period Expressing readiness to remain in the study for the entire study period Married men should use safe methods of contraception up to three months after the second vaccine dose

Exclusion criteria:

Any acute or chronic symptomatic disease requiring ongoing medical or surgical care at the screening day Healthcare workers Breastfeeding History of receiving any vaccine (whether investigational or non-investigational) within 30 days prior to the screening day History of receiving other investigational drugs within 60 days prior to the screening day History of receiving blood or any blood product or immunoglobulin within three months prior to the screening day History of Immunodeficiency disorders (suspected or definite) History of long-term use of immunosuppressive drugs (more than 14 consecutive days) within four months prior to the screening day History of long-term use (more than 14 consecutive days) of systemic corticosteroids (equivalent to 10 mg or more daily prednisolone) or high-dose inhaled steroids (more than 800 µg/day of beclomethasone dipropionate or equivalent) within four months prior to the screening day (excluding topical steroids) History of allergic diseases such as angioedema or anaphylaxis History of any known allergy to drugs or vaccines including aluminum phosphate and albumin History of known allergy to eggs History of autoimmune diseases Chemotherapy or radiotherapy in the last 5 years History of cancer in the last 5 years History of serious psychiatric illnesses History of blood disorders (dyscrasia, coagulation disorders, platelet deficiency or disorder, deficiency of blood factors) History of chronic obstructive pulmonary disease such as asthma diagnosed by a specialist History of ischemic heart disease currently treated by a cardiologist or receiving any cardiac interventions History of hypertension currently treated by a physician History of diabetes currently treated by a physician Congenital anomalies, growth retardation, genetic defects or severe malnutrition Individual or family history of chronic neurological diseases (including seizures and epilepsy) History of thyroid disease or Thyroidectomy Any history of substance or alcohol abuse in the past 2 years Abnormal hematological or biochemical test results at the time of screening History of confirmed COVID-19 Acute febrile illness at the time of vaccination History of allergy to acetaminophen History of acute or chronic hepatitis B and C History of pulmonary or extrapulmonary tuberculosis or receiving antituberculotic treatment Receiving tuberculosis prophylaxis History of faint in any encounter with needles or phlebectomy Splenectomy for any reason or history of abnormal spleen function Any close contact with a confirmed COVID-19 case up to two weeks before receiving the first vaccine dose Previous history of diseases such as SARS and MERS Not fit to participate in the trial (the decision is at the discretion of the chief investigator) People who are currently serving their obligatory military service in the Armed Forces

Target sample size: 135

Actual sample size reached: 135