Immunogenicity and Safety of the Yellow Fever Vaccine in HIV Infected Individuals

Inclusion Criteria: * HIV infected adults, age \>= 18 and \<60 years old. * CD4 \> 200 cells/mm³ within the last 6 months prior to inclusion. Individuals with no CD4 results in the last 6 months which have undetectable HIV viral load and last CD4 count \> 350 can be included. * Healthy HIV-uninfected individuals (aged \>= 18 and \< 60) * No history of Yellow Fever vaccination * Willing to participate and to sign the consent Exclusion Criteria: * Individuals with chronic diseases such as: decompensated diabetes, kidney failure (in dialysis), liver failure/cirrhosis, cancer (except for non-melanoma skin cancer and in situ HIV related carcinoma), use of immunosuppressive agents (including prednisone ≥ 20mg/day, during 7 or more days in the last 30 days before inclusion). * Pregnant women * Hypersensitivity reaction to eggs, chicken protein. Allergy to erythomycin or kanamycin. Hereditary fructose intolerance. * Administration of immunoglobulins or blood derivates \< 3 months or life attenuated vaccine \<1 month. * History of thymic dysfunction (including thymoma and thymectomy). * Use of anti-CCR5 * symptoms of severe acute illnesses or fever (axillary temperature ≥ 38°C) * HIV positive rapid test for HIV negative subjects.