* 1. spo2 ≤ 91% breathing ambient air and spo2 \< 95% with oxygen in nasal cannula at 2 lpm. * 2. patient's attending physician considers the study is not the best medical option, or follow-up after discharge will be difficult. * 3. a patient who, in the investigator's opinion, is unlikely to survive \> 48 hours from inclusion in the study. * 4. patients with severe chronic kidney disease (clcr \< 30 ml/min/1.73 m2 or receiving renal replacement therapy in any of its modalities). * 5. severe liver disease (child-pugh c, alt \> 5 times above upper limit of normal (lsn). * 6. copd with fev1 \< 70. * 7. known active neoplasia. * 8. hiv infection. patients with known hiv infection, under follow-up, and immunovirological stability (cd4\> 500 and undetectable viral load) for at least 6 months before inclusion in this study may be included. * 9. hemoglobin \< 9 gr/dl. * 10. prolonged qt, defined as a qt interval \> 460 ms. (or \> 450 ms. in case of family history of sudden death or long qt syndrome or personal history of repeat syncope without an etiological diagnosis). this criterion will only apply if the standard treatment contains drugs with an effect on the duration (prolongation) of the qt interval. * 11.significant cardiovascular disease, including: 1. history of acute myocardial infarction, acute coronary syndrome (unstable angina, coronary by-pass surgery, angioplasty, or coronary stenting) ≤ 6 months prior to randomization 2. symptomatic heart failure (nyha grade 2 or more) history, or current evidence of cardiac arrhythmia (except atrial fibrillation or flutter and paroxysmal supraventricular tachycardia) and/or conduction abnormalities (excluding branch blocks or wenckebach grade i and ii atrioventricular blocks). * 12. known or suspected active autoimmune disease * 13. pregnancy or breastfeeding, or positive pregnancy test at baseline or screening visit * 14. patients who are expected to be transferred to another facility sooner than 72 hours after inclusion in the study. * 15. patients who have received experimental treatment (off-label, compassionate use, or in clinical trials) within 30 days prior to the screening visit, except for treatment considered standard initiated on admission to hospital, up to 48 hours before inclusion in the study. * 16. patients who have a history of allergic reactions to maraviroc or any of its components.

* 1. spo2 ≤ 91% breathing ambient air and spo2 \< 95% with oxygen in nasal cannula at 2 lpm. * 2. patient's attending physician considers the study is not the best medical option, or follow-up after discharge will be difficult. * 3. a patient who, in the investigator's opinion, is unlikely to survive \> 48 hours from inclusion in the study. * 4. patients with severe chronic kidney disease (clcr \< 30 ml/min/1.73 m2 or receiving renal replacement therapy in any of its modalities). * 5. severe liver disease (child-pugh c, alt \> 5 times above upper limit of normal (lsn). * 6. copd with fev1 \< 70. * 7. known active neoplasia. * 8. hiv infection. patients with known hiv infection, under follow-up, and immunovirological stability (cd4\> 500 and undetectable viral load) for at least 6 months before inclusion in this study may be included. * 9. hemoglobin \< 9 gr/dl. * 10. prolonged qt, defined as a qt interval \> 460 ms. (or \> 450 ms. in case of family history of sudden death or long qt syndrome or personal history of repeat syncope without an etiological diagnosis). this criterion will only apply if the standard treatment contains drugs with an effect on the duration (prolongation) of the qt interval. * 11.significant cardiovascular disease, including: 1. history of acute myocardial infarction, acute coronary syndrome (unstable angina, coronary by-pass surgery, angioplasty, or coronary stenting) ≤ 6 months prior to randomization 2. symptomatic heart failure (nyha grade 2 or more) history, or current evidence of cardiac arrhythmia (except atrial fibrillation or flutter and paroxysmal supraventricular tachycardia) and/or conduction abnormalities (excluding branch blocks or wenckebach grade i and ii atrioventricular blocks). * 12. known or suspected active autoimmune disease * 13. pregnancy or breastfeeding, or positive pregnancy test at baseline or screening visit * 14. patients who are expected to be transferred to another facility sooner than 72 hours after inclusion in the study. * 15. patients who have received experimental treatment (off-label, compassionate use, or in clinical trials) within 30 days prior to the screening visit, except for treatment considered standard initiated on admission to hospital, up to 48 hours before inclusion in the study. * 16. patients who have a history of allergic reactions to maraviroc or any of its components.

1. spo2 ≤ 91% breathing ambient air and spo2 < 95% with oxygen in nasal cannula at 2 lpm. 2. patient's attending physician considers the study is not the best medical option, or follow-up after discharge will be difficult. 3. a patient who, in the investigator's opinion, is unlikely to survive > 48 hours from inclusion in the study. 4. patients with severe chronic kidney disease (clcr < 30 ml/min/1.73 m2 or receiving renal replacement therapy in any of its modalities). 5. severe liver disease (child-pugh c, alt > 5 times above upper limit of normal (lsn). 6. copd with fev1 < 70. 7. known active neoplasia. 8. hiv infection. patients with known hiv infection, under follow-up, and immunovirological stability (cd4> 500 and undetectable viral load) for at least 6 months before inclusion in this study may be included. 9. hemoglobin < 9 gr/dl. 10. prolonged qt, defined as a qt interval > 460 ms. (or > 450 ms. in case of family history of sudden death or long qt syndrome or personal history of repeat syncope without an etiological diagnosis). this criterion will only apply if the standard treatment contains drugs with an effect on the duration (prolongation) of the qt interval. 11.significant cardiovascular disease, including: history of acute myocardial infarction, acute coronary syndrome (unstable angina, coronary by-pass surgery, angioplasty, or coronary stenting) ≤ 6 months prior to randomization symptomatic heart failure (nyha grade 2 or more) history, or current evidence of cardiac arrhythmia (except atrial fibrillation or flutter and paroxysmal supraventricular tachycardia) and/or conduction abnormalities (excluding branch blocks or wenckebach grade i and ii atrioventricular blocks). 12. known or suspected active autoimmune disease 13. pregnancy or breastfeeding, or positive pregnancy test at baseline or screening visit 14. patients who are expected to be transferred to another facility sooner than 72 hours after inclusion in the study. 15. patients who have received experimental treatment (off-label, compassionate use, or in clinical trials) within 30 days prior to the screening visit, except for treatment considered standard initiated on admission to hospital, up to 48 hours before inclusion in the study. 16. patients who have a history of allergic reactions to maraviroc or any of its components.

1. spo2 ≤ 91% breathing ambient air and spo2 < 95% with oxygen in nasal cannula at 2 lpm. 2. patient's attending physician considers the study is not the best medical option, or follow-up after discharge will be difficult. 3. a patient who, in the investigator's opinion, is unlikely to survive > 48 hours from inclusion in the study. 4. patients with severe chronic kidney disease (clcr < 30 ml/min/1.73 m2 or receiving renal replacement therapy in any of its modalities). 5. severe liver disease (child-pugh c, alt > 5 times above upper limit of normal (lsn). 6. copd with fev1 < 70. 7. known active neoplasia. 8. hiv infection. patients with known hiv infection, under follow-up, and immunovirological stability (cd4> 500 and undetectable viral load) for at least 6 months before inclusion in this study may be included. 9. hemoglobin < 9 gr/dl. 10. prolonged qt, defined as a qt interval > 460 ms. (or > 450 ms. in case of family history of sudden death or long qt syndrome or personal history of repeat syncope without an etiological diagnosis). this criterion will only apply if the standard treatment contains drugs with an effect on the duration (prolongation) of the qt interval. 11.significant cardiovascular disease, including: history of acute myocardial infarction, acute coronary syndrome (unstable angina, coronary by-pass surgery, angioplasty, or coronary stenting) ≤ 6 months prior to randomization symptomatic heart failure (nyha grade 2 or more) history, or current evidence of cardiac arrhythmia (except atrial fibrillation or flutter and paroxysmal supraventricular tachycardia) and/or conduction abnormalities (excluding branch blocks or wenckebach grade i and ii atrioventricular blocks). 12. known or suspected active autoimmune disease 13. pregnancy or breastfeeding, or positive pregnancy test at baseline or screening visit 14. patients who are expected to be transferred to another facility sooner than 72 hours after inclusion in the study. 15. patients who have received experimental treatment (off-label, compassionate use, or in clinical trials) within 30 days prior to the screening visit, except for treatment considered standard initiated on admission to hospital, up to 48 hours before inclusion in the study. 16. patients who have a history of allergic reactions to maraviroc or any of its components.

- 1. spo2 ≤ 91% breathing ambient air and spo2 < 95% with oxygen in nasal cannula at 2 lpm. - 2. patient's attending physician considers the study is not the best medical option, or follow-up after discharge will be difficult. - 3. a patient who, in the investigator's opinion, is unlikely to survive > 48 hours from inclusion in the study. - 4. patients with severe chronic kidney disease (clcr < 30 ml/min/1.73 m2 or receiving renal replacement therapy in any of its modalities). - 5. severe liver disease (child-pugh c, alt > 5 times above upper limit of normal (lsn). - 6. copd with fev1 < 70. - 7. known active neoplasia. - 8. hiv infection. patients with known hiv infection, under follow-up, and immunovirological stability (cd4> 500 and undetectable viral load) for at least 6 months before inclusion in this study may be included. - 9. hemoglobin < 9 gr/dl. - 10. prolonged qt, defined as a qt interval > 460 ms. (or > 450 ms. in case of family history of sudden death or long qt syndrome or personal history of repeat syncope without an etiological diagnosis). this criterion will only apply if the standard treatment contains drugs with an effect on the duration (prolongation) of the qt interval. - 11.significant cardiovascular disease, including: 1. history of acute myocardial infarction, acute coronary syndrome (unstable angina, coronary by-pass surgery, angioplasty, or coronary stenting) ≤ 6 months prior to randomization 2. symptomatic heart failure (nyha grade 2 or more) history, or current evidence of cardiac arrhythmia (except atrial fibrillation or flutter and paroxysmal supraventricular tachycardia) and/or conduction abnormalities (excluding branch blocks or wenckebach grade i and ii atrioventricular blocks). - 12. known or suspected active autoimmune disease - 13. pregnancy or breastfeeding, or positive pregnancy test at baseline or screening visit - 14. patients who are expected to be transferred to another facility sooner than 72 hours after inclusion in the study. - 15. patients who have received experimental treatment (off-label, compassionate use, or in clinical trials) within 30 days prior to the screening visit, except for treatment considered standard initiated on admission to hospital, up to 48 hours before inclusion in the study. - 16. patients who have a history of allergic reactions to maraviroc or any of its components.

- 1. spo2 ≤ 91% breathing ambient air and spo2 < 95% with oxygen in nasal cannula at 2 lpm. - 2. patient's attending physician considers the study is not the best medical option, or follow-up after discharge will be difficult. - 3. a patient who, in the investigator's opinion, is unlikely to survive > 48 hours from inclusion in the study. - 4. patients with severe chronic kidney disease (clcr < 30 ml/min/1.73 m2 or receiving renal replacement therapy in any of its modalities). - 5. severe liver disease (child-pugh c, alt > 5 times above upper limit of normal (lsn). - 6. copd with fev1 < 70. - 7. known active neoplasia. - 8. hiv infection. patients with known hiv infection, under follow-up, and immunovirological stability (cd4> 500 and undetectable viral load) for at least 6 months before inclusion in this study may be included. - 9. hemoglobin < 9 gr/dl. - 10. prolonged qt, defined as a qt interval > 460 ms. (or > 450 ms. in case of family history of sudden death or long qt syndrome or personal history of repeat syncope without an etiological diagnosis). this criterion will only apply if the standard treatment contains drugs with an effect on the duration (prolongation) of the qt interval. - 11.significant cardiovascular disease, including: 1. history of acute myocardial infarction, acute coronary syndrome (unstable angina, coronary by-pass surgery, angioplasty, or coronary stenting) ≤ 6 months prior to randomization 2. symptomatic heart failure (nyha grade 2 or more) history, or current evidence of cardiac arrhythmia (except atrial fibrillation or flutter and paroxysmal supraventricular tachycardia) and/or conduction abnormalities (excluding branch blocks or wenckebach grade i and ii atrioventricular blocks). - 12. known or suspected active autoimmune disease - 13. pregnancy or breastfeeding, or positive pregnancy test at baseline or screening visit - 14. patients who are expected to be transferred to another facility sooner than 72 hours after inclusion in the study. - 15. patients who have received experimental treatment (off-label, compassionate use, or in clinical trials) within 30 days prior to the screening visit, except for treatment considered standard initiated on admission to hospital, up to 48 hours before inclusion in the study. - 16. patients who have a history of allergic reactions to maraviroc or any of its components.