1. severe illness enough to require hospitalization or already meeting the study's primary endpoint for clinical deterioration 2. patients who cannot take oral medication 3. pregnancy or breastfeeding 4. history of the psychiatric disorder including major depressive disorder 5. patients who are taking or took selective serotonin reuptake inhibitors, serotonin and noradrenaline reuptake inhibitor, or tricyclic anti-depressants within 2 weeks 6. patients who are taking an anti-epileptic drug 7. patients who are taking co-prescribed drugs (as below) which are contraindicated by manufacturers due to drug-drug interaction * alosetron, tizanidine, theophylline, clozapine, olanzapine (drugs with a narrow therapeutic index that are primarily metabolized by cytochrome p450 1a2) * donepezil, sertraline (sigma-1 receptor agonists) * warfarin (increased risk of bleeding) * phenytoin (rationale: fluvoxamine inhibits its metabolism) * clopidogrel (fluvoxamine inhibits its metabolism from pro-drug to active drug which raises the risk of cardiovascular events) * monoamine oxidase inhibitors (linezolid, rasagiline, selegiline), triptans (sumatriptan, naratriptan, almotriptan, frovatriptan, zolmitriptan, rizatriptan), lithium, tramadol (rationale: to prevent the possible development of serotonin syndrome) * alprazolam, diazepam (fluvoxamine modestly inhibits the metabolism of these drugs): the patient could be enrolled in case of agreeing 25% dose reduction of these medications. 8. already enrolled in another covid-19 medication trial 9. medical comorbidities such as severe underlying lung disease (chronic obstructive pulmonary disease on home oxygen, interstitial lung disease, pulmonary hypertension), decompensated cirrhosis, chronic viral hepatitis, congestive heart failure (stage 3 or 4 per patient report and/or medical records), chronic kidney disease, or end-stage renal disease requiring renal replacement therapy 10. immunocompromised (solid organ transplant, bone-marrow transplant, acquired immune deficiency syndrome, on biologics and/or high dose steroids \[\>20mg prednisone per day\]) 11. unable to provide informed consent (e.g., moderate-severe dementia diagnosis) 12. unable to perform the study procedures (self-assessment of oxygen saturation, blood pressure, and temperature using self-monitoring equipment)

1. severe illness enough to require hospitalization or already meeting the study's primary endpoint for clinical deterioration 2. patients who cannot take oral medication 3. pregnancy or breastfeeding 4. history of the psychiatric disorder including major depressive disorder 5. patients who are taking or took selective serotonin reuptake inhibitors, serotonin and noradrenaline reuptake inhibitor, or tricyclic anti-depressants within 2 weeks 6. patients who are taking an anti-epileptic drug 7. patients who are taking co-prescribed drugs (as below) which are contraindicated by manufacturers due to drug-drug interaction * alosetron, tizanidine, theophylline, clozapine, olanzapine (drugs with a narrow therapeutic index that are primarily metabolized by cytochrome p450 1a2) * donepezil, sertraline (sigma-1 receptor agonists) * warfarin (increased risk of bleeding) * phenytoin (rationale: fluvoxamine inhibits its metabolism) * clopidogrel (fluvoxamine inhibits its metabolism from pro-drug to active drug which raises the risk of cardiovascular events) * monoamine oxidase inhibitors (linezolid, rasagiline, selegiline), triptans (sumatriptan, naratriptan, almotriptan, frovatriptan, zolmitriptan, rizatriptan), lithium, tramadol (rationale: to prevent the possible development of serotonin syndrome) * alprazolam, diazepam (fluvoxamine modestly inhibits the metabolism of these drugs): the patient could be enrolled in case of agreeing 25% dose reduction of these medications. 8. already enrolled in another covid-19 medication trial 9. medical comorbidities such as severe underlying lung disease (chronic obstructive pulmonary disease on home oxygen, interstitial lung disease, pulmonary hypertension), decompensated cirrhosis, chronic viral hepatitis, congestive heart failure (stage 3 or 4 per patient report and/or medical records), chronic kidney disease, or end-stage renal disease requiring renal replacement therapy 10. immunocompromised (solid organ transplant, bone-marrow transplant, acquired immune deficiency syndrome, on biologics and/or high dose steroids \[\>20mg prednisone per day\]) 11. unable to provide informed consent (e.g., moderate-severe dementia diagnosis) 12. unable to perform the study procedures (self-assessment of oxygen saturation, blood pressure, and temperature using self-monitoring equipment)

severe illness enough to require hospitalization or already meeting the study's primary endpoint for clinical deterioration patients who cannot take oral medication pregnancy or breastfeeding history of the psychiatric disorder including major depressive disorder patients who are taking or took selective serotonin reuptake inhibitors, serotonin and noradrenaline reuptake inhibitor, or tricyclic anti-depressants within 2 weeks patients who are taking an anti-epileptic drug patients who are taking co-prescribed drugs (as below) which are contraindicated by manufacturers due to drug-drug interaction alosetron, tizanidine, theophylline, clozapine, olanzapine (drugs with a narrow therapeutic index that are primarily metabolized by cytochrome p450 1a2) donepezil, sertraline (sigma-1 receptor agonists) warfarin (increased risk of bleeding) phenytoin (rationale: fluvoxamine inhibits its metabolism) clopidogrel (fluvoxamine inhibits its metabolism from pro-drug to active drug which raises the risk of cardiovascular events) monoamine oxidase inhibitors (linezolid, rasagiline, selegiline), triptans (sumatriptan, naratriptan, almotriptan, frovatriptan, zolmitriptan, rizatriptan), lithium, tramadol (rationale: to prevent the possible development of serotonin syndrome) alprazolam, diazepam (fluvoxamine modestly inhibits the metabolism of these drugs): the patient could be enrolled in case of agreeing 25% dose reduction of these medications. already enrolled in another covid-19 medication trial medical comorbidities such as severe underlying lung disease (chronic obstructive pulmonary disease on home oxygen, interstitial lung disease, pulmonary hypertension), decompensated cirrhosis, chronic viral hepatitis, congestive heart failure (stage 3 or 4 per patient report and/or medical records), chronic kidney disease, or end-stage renal disease requiring renal replacement therapy immunocompromised (solid organ transplant, bone-marrow transplant, acquired immune deficiency syndrome, on biologics and/or high dose steroids [>20mg prednisone per day]) unable to provide informed consent (e.g., moderate-severe dementia diagnosis) unable to perform the study procedures (self-assessment of oxygen saturation, blood pressure, and temperature using self-monitoring equipment)

severe illness enough to require hospitalization or already meeting the study's primary endpoint for clinical deterioration patients who cannot take oral medication pregnancy or breastfeeding history of the psychiatric disorder including major depressive disorder patients who are taking or took selective serotonin reuptake inhibitors, serotonin and noradrenaline reuptake inhibitor, or tricyclic anti-depressants within 2 weeks patients who are taking an anti-epileptic drug patients who are taking co-prescribed drugs (as below) which are contraindicated by manufacturers due to drug-drug interaction alosetron, tizanidine, theophylline, clozapine, olanzapine (drugs with a narrow therapeutic index that are primarily metabolized by cytochrome p450 1a2) donepezil, sertraline (sigma-1 receptor agonists) warfarin (increased risk of bleeding) phenytoin (rationale: fluvoxamine inhibits its metabolism) clopidogrel (fluvoxamine inhibits its metabolism from pro-drug to active drug which raises the risk of cardiovascular events) monoamine oxidase inhibitors (linezolid, rasagiline, selegiline), triptans (sumatriptan, naratriptan, almotriptan, frovatriptan, zolmitriptan, rizatriptan), lithium, tramadol (rationale: to prevent the possible development of serotonin syndrome) alprazolam, diazepam (fluvoxamine modestly inhibits the metabolism of these drugs): the patient could be enrolled in case of agreeing 25% dose reduction of these medications. already enrolled in another covid-19 medication trial medical comorbidities such as severe underlying lung disease (chronic obstructive pulmonary disease on home oxygen, interstitial lung disease, pulmonary hypertension), decompensated cirrhosis, chronic viral hepatitis, congestive heart failure (stage 3 or 4 per patient report and/or medical records), chronic kidney disease, or end-stage renal disease requiring renal replacement therapy immunocompromised (solid organ transplant, bone-marrow transplant, acquired immune deficiency syndrome, on biologics and/or high dose steroids [>20mg prednisone per day]) unable to provide informed consent (e.g., moderate-severe dementia diagnosis) unable to perform the study procedures (self-assessment of oxygen saturation, blood pressure, and temperature using self-monitoring equipment)

1. severe illness enough to require hospitalization or already meeting the study's primary endpoint for clinical deterioration 2. patients who cannot take oral medication 3. pregnancy or breastfeeding 4. history of the psychiatric disorder including major depressive disorder 5. patients who are taking or took selective serotonin reuptake inhibitors, serotonin and noradrenaline reuptake inhibitor, or tricyclic anti-depressants within 2 weeks 6. patients who are taking an anti-epileptic drug 7. patients who are taking co-prescribed drugs (as below) which are contraindicated by manufacturers due to drug-drug interaction - alosetron, tizanidine, theophylline, clozapine, olanzapine (drugs with a narrow therapeutic index that are primarily metabolized by cytochrome p450 1a2) - donepezil, sertraline (sigma-1 receptor agonists) - warfarin (increased risk of bleeding) - phenytoin (rationale: fluvoxamine inhibits its metabolism) - clopidogrel (fluvoxamine inhibits its metabolism from pro-drug to active drug which raises the risk of cardiovascular events) - monoamine oxidase inhibitors (linezolid, rasagiline, selegiline), triptans (sumatriptan, naratriptan, almotriptan, frovatriptan, zolmitriptan, rizatriptan), lithium, tramadol (rationale: to prevent the possible development of serotonin syndrome) - alprazolam, diazepam (fluvoxamine modestly inhibits the metabolism of these drugs): the patient could be enrolled in case of agreeing 25% dose reduction of these medications. 8. already enrolled in another covid-19 medication trial 9. medical comorbidities such as severe underlying lung disease (chronic obstructive pulmonary disease on home oxygen, interstitial lung disease, pulmonary hypertension), decompensated cirrhosis, chronic viral hepatitis, congestive heart failure (stage 3 or 4 per patient report and/or medical records), chronic kidney disease, or end-stage renal disease requiring renal replacement therapy 10. immunocompromised (solid organ transplant, bone-marrow transplant, acquired immune deficiency syndrome, on biologics and/or high dose steroids [>20mg prednisone per day]) 11. unable to provide informed consent (e.g., moderate-severe dementia diagnosis) 12. unable to perform the study procedures (self-assessment of oxygen saturation, blood pressure, and temperature using self-monitoring equipment)

1. severe illness enough to require hospitalization or already meeting the study's primary endpoint for clinical deterioration 2. patients who cannot take oral medication 3. pregnancy or breastfeeding 4. history of the psychiatric disorder including major depressive disorder 5. patients who are taking or took selective serotonin reuptake inhibitors, serotonin and noradrenaline reuptake inhibitor, or tricyclic anti-depressants within 2 weeks 6. patients who are taking an anti-epileptic drug 7. patients who are taking co-prescribed drugs (as below) which are contraindicated by manufacturers due to drug-drug interaction - alosetron, tizanidine, theophylline, clozapine, olanzapine (drugs with a narrow therapeutic index that are primarily metabolized by cytochrome p450 1a2) - donepezil, sertraline (sigma-1 receptor agonists) - warfarin (increased risk of bleeding) - phenytoin (rationale: fluvoxamine inhibits its metabolism) - clopidogrel (fluvoxamine inhibits its metabolism from pro-drug to active drug which raises the risk of cardiovascular events) - monoamine oxidase inhibitors (linezolid, rasagiline, selegiline), triptans (sumatriptan, naratriptan, almotriptan, frovatriptan, zolmitriptan, rizatriptan), lithium, tramadol (rationale: to prevent the possible development of serotonin syndrome) - alprazolam, diazepam (fluvoxamine modestly inhibits the metabolism of these drugs): the patient could be enrolled in case of agreeing 25% dose reduction of these medications. 8. already enrolled in another covid-19 medication trial 9. medical comorbidities such as severe underlying lung disease (chronic obstructive pulmonary disease on home oxygen, interstitial lung disease, pulmonary hypertension), decompensated cirrhosis, chronic viral hepatitis, congestive heart failure (stage 3 or 4 per patient report and/or medical records), chronic kidney disease, or end-stage renal disease requiring renal replacement therapy 10. immunocompromised (solid organ transplant, bone-marrow transplant, acquired immune deficiency syndrome, on biologics and/or high dose steroids [>20mg prednisone per day]) 11. unable to provide informed consent (e.g., moderate-severe dementia diagnosis) 12. unable to perform the study procedures (self-assessment of oxygen saturation, blood pressure, and temperature using self-monitoring equipment)