Phase 3 Clinical Trial to evaluate the Immunogenicity and Safety of Covid19 Recombinant RBD Protein Vaccine (Noora Vaccine) as a Booster Vaccine after injection of existing Vaccines in IRAN

INTERVENTION: Intervention 1: Intervention Group: Injection of a dose of 80 micrograms of recombinant RBD protein vaccine intramuscularly (deltoid muscle) in 10000 participants in affiliated centers of Baqiyatallah Hospital and 200 participants in Shahid Soleimani Clinical Trial Center. Intervention 2: Control group: Injection of a placebo intramuscularly (deltoid muscle) in 100 participants in Shahid Soleimani Clinical Trial Center. CONDITION: Covid 19. ; COVID 19, virus identified U07.1 PRIMARY OUTCOME: ?The level of specific IgG antibody against RBD protein in days 0 and 21 after booster injection based on GMI, GMT and seroconversion rate (increase at least 4 times in antibody titer) in Shahid Soleimani Clinical Trial Center (sample of 300 people). Timepoint: in days 0 and 21 after booster injection. Method of measurement: The level of specific IgG antibody against RBD protein ibased on GMI, GMT and seroconversion rate (increase at least 4 times in antibody titer) . Cellular immune response to booster dose based on measurement of IL 4 and INF? levels using ELISA method on days 0 and 21 after injection (subgroup of 90 people). Timepoint: in days 0 and 21 after booster injection. Method of measurement: Cellular immune response to booster dose based on measurement of IL 4 and INF? levels using ELISA method . Measurement of neutralizing antibody level by neutralization test method Virus (subgroup of 90 people). Timepoint: in days 0 and 21 after booster injection. Method of measurement: Measurement of neutralizing antibody level by neutralization test method Virus. INCLUSION CRITERIA: Age 18 years and older Candidates who have received two identical doses of the available vaccine (Sinopharm, CovIran Barakat, AstraZenka) and at least 3 months (at least 90 days) have passed since the second dose The candidate is able to fully understand the provisions of the informed consent form and sign it before entering the study SECONDARY OUTCOME: Any reaction within 30 minutes after booster dose injection. Timepoint: within 30 minutes after booster dose injection. Method of measurement: ?Data collection and recording by the nurse or physician based on the participating condition within 30 minutes after injection at the vaccination site. Incidence of adverse event (s) Systemic (fever, headache, chills, diarrhea, vomiting, muscle aches, joint pain, shortness of breath, fatigue, allergic reactions, etc.) based on the severity, duration and maximum severity of the complication within 60 days after booster dose as a complementary outcome. Timepoint: within 60 days after booster dose. Method of measurement: ?Experts contact participants and record possible side effects. Incidence of adverse event (s) Systemic (fever, headache, chills, diarrhea, vomiting, muscle aches, joint pain, shortness of breath,fatigue, allergic reactions, etc.) based on the severity, duration and maximum severity of the complication within 28 days after booster dose. Timepoint: within 28 days after booster dose. Method of measurement: ?Experts contact participants and record possible side effects. Level of IgG antibody specific against RBD protein in 3 and 6 months after booster dose injection and seroconversion rate (increase at least 4 times in antibody titer) in the vaccine group in Shahid Soleimani Clinical Trial Center (group of 200 people) as a complementary outcome. Timepoint: in 3 and 6 months after booster dose injection. Method of measurement: collecting blood samples of vaccine participants (200 people) in Shahid Soleimani Trial Center. Occurrence of local adverse event (s) (pain, redness, stiffness, swelling, skin rash, burning and itching) or systemic (fever, headache, chills, diarrhea) Vomiting, muscle pain, joint pain, shortness of breath, fatigue, allergic reactions, etc.) based on the severity, duration and maximum severity of the complication within 3 and 7 days after injection of the booster dose. Timepoint: within 3 and 7 days after injection of the booster dose. Method of measurement: ?Experts contact participants and record possible side effects.