Eligibility Criteria:
Inclusion Criteria:
* HIV-1 infected patient,
* Age between 18 and 60 years,
* ART (Anti Retroviral Therapy) initiation ≥ 1 year ago,
* Plasma HIV RNA ≤ 200 copies/ml in the past 12 months,
* Plasma HIV RNA ≤ 50 copies/ml at the screening visit,
* CD4+ T cell count ≥ 200 cells/mm3,
* Nadir CD4+ T cell count ≥ 100 cells/mm3,
* Contraception in women with child-bearing potential,
* A total anti-3S titer ≥ 20 A.U. at any time point of IVVAC-3S/P1 clinical trial,
* Per protocol subject having completed the IVVAC-3S/P1 study.
* Patient affiliated to a social security system,
* Patient who has understood the protocol design and provided a signed written informed consent form,
* Patient who is willing and capable of cooperating to the extent and degree required by the protocol,
* Patient whom the investigator believes he/she can and will comply with the requirements of the protocol (e.g. completion of the diary cards, return for follow-up visits) and he/she will be available for all scheduled visits at the investigational site.
Exclusion Criteria:
* Administration of VAC-3S in the past year,
* Chronic active liver disease,
* History of HCV co-infection or ongoing replicating HCV (positive RT-PCR) or HBV (positive HbS Ag) coinfection,
* Any immunotherapy (e.g. IL-2, IL-7, growth hormone…) in the past year at the exception of VAC-3S,
* Any immunosuppressive therapy (glucocorticoids, cyclosporine, methotrexate) or chronic non-steroidal anti-inflammatory treatment in the past month,
* Ongoing pregnancy,
* Breastfeeding women,
* Patient with known sensitivities to investigational drug (see please the CIB),
* History of allergy to any vaccine,
* Any severe chronic condition that would interfere with the study,
* History of auto-immune disease,
* Organ transplant,
* Splenectomy,
* Psychiatric disorder significant enough to hinder participation as assessed by the investigator,
* Patient who has participated in a clinical research trial in the 30 days preceding the screening visit (V-1M-1).
* Patients with contraindications to intramuscular injections including, but not limited to, patients with thrombocytopenia and/or anomalies of the coagulation system,
* Any uncontrolled chronic or acute condition that in the opinion of the investigator would compromise the safety of the patient or the ability to properly administer the study.