A Phase IIb/III Clinical Trial to Assess Safety and Immunogenicity of a COVID-19 Vaccine Booster Dose in Immunosupressed Adults.

Inclusion Criteria:

• Male, female or transgender, ≥ 18 years old at Day 0.

• Provide inform consent form

• Participant who has:

• 3 doses of mRNA vaccines

• 2 doses of mRNA vaccines and previous COVID-19 infection

• 2 doses of Coronavac and 1 Comirnaty, or, 1 Coronavac and 2 Comirnaty

• Participant who has:

• HIV infection with CD4 Tcells counts <400

• Primary antibody deficiency disorders

• Kidney disease on dialysis

• Kidney transplant at least >1 year

• Auto Immune Disease (AID) in treatment with rituximab

• For a female of childbearing potential, to have a negative pregnancy test at Day 0

• Use of any of these contraception:

• Female: hormonal contraception, intrauterine device, vasectomized partner, sexualabstinence, condom.

• Male: Vasectomized participant, sexual abstinence, condom.

Exclusion Criteria:

• History of anaphylaxis to any prior vaccine

• Participants has received or plans to receive live attenuated vaccines, other notlive vaccines, or Vaxzevria or Janssen vaccines.

• Pregnant or breast-feeding at Day 0.

• A confirmed COVID-19 diagnose <90 days prior to vaccination day 0.

• A clinically significant acute illness or fever at screening or 48h before day 0.

• Participant had a surgery requiring hospitalisation and has not received thehospital discharge.

• Participant has an ongoing severe and non-stable psychiatric condition

• Participant has a problematic or risky use of substances including alcohol

• Participant has a bleeding disorder that contraindicates intramuscular injection

• Participant suffering from post-acute COVID-19 syndrome / long COVID

• Participant received any immunotherapy to prevent/treat COVID-19 in the last 90 days

• Participant is already participating in another research involving drug, biologicsor device

• Participant has donated ≥450 ml of blood products within 12 weeks before screening

• Participant has any medical condition and/or finding that in the investigatoropinion might increase participant risk, interfere with the study or impairinterpretation of study data.