Patients eligible for the study will be selected on Fridays during the HIV consultation at the Infectious Diseases Department. Patients that meet the inclusion and exclusion criteria will be randomly assigned to two groups. One group will start intervention with FMT (fecal matter transplant) through frozen capsules and after seven days, antiretroviral therapy (ART) will be started. Patients in the other group will be given placebo capsules instead before starting ART. The frozen capsules of FMT will be ingested orally with a frequency of 15 capsules every 12 hours for 4 doses 7 days prior ART start and on weeks 0, 4, 8 and 12 after ART start. Subsequently, blood samples will be taken to monitor the immune status with CD4 T lymphocytes and HIV viral load during week 0, 4, 8, 12 and 24 after ART start. Throughout the study period, subjects can carry out a free diet, moderate alcohol intake, perform their daily activities and abstain from any of the elimination criteria. Medical consultations will be made on days -7 to ART start, day 1, 30, 60, 90 and 120 after ART start, where clinical examination and elimination criteria will be evaluated. Neither patients nor investigators know which group of patients will receive placebo and which one fecal microbiota capsules. The laboratory that provides us the capsules is going to divide and randomize our sample of patients and register the information in a data base.

What type of study is this? O Observational study: prospective O Observational study: cross-sectional Observational study: retrospective Experiment: completely randomized design O Experiment: matched pairs design O Experiment: randomized block design 27 1 point Identify the following terms in the context of this study: Experimental Units Whether the patient ha Explanatory Variable > Response Variables > Treatment 1 point What type of blinding will be used, if any? Single-blind Double-blind O No blinding will be used What type of study is this? O Observational study: prospective O Observational study: cross-sectional Observational study: retrospective Experiment: completely randomized design O Experiment: matched pairs design O Experiment: randomized block design 27 1 point Identify the following terms in the context of this study: Experimental Units Whether the patient ha Explanatory Variable > Response Variables > Treatment 1 point What type of blinding will be used, if any? Single-blind Double-blind O No blinding will be used