- mild covid-19 at randomisation (each of the followings met): no dyspnoea, respiratory rate < 22 / min, no need for oxygen supplementation, no pneumonia on medical imaging - severe covid-19 at randomisation: respiratory distress - respiratory rate ≥ 30/min, oxygen saturation at rest ≤ 93%, pulmonary infiltrates occupy > 50% of the lung-fields - critical covid-19 at randomisation: acute respiratory distress, requiring mechanical ventilation, radiomorphology of ards, shock, including septic shock, other organ dysfunction necessitating icu admission - high-risk patient for progression of covid-19, as defined by having a calculated pneumonia port-score of > 90 - concomitant or previous administration of any experimental, non-established covid-19 therapy, either in off-label indication (of a registered medicinal product) or as a non-registered drug candidate in a clinical trial setting or compassionate use program (or equivalents thereof), except therapies recommended by the "magyar koronavírus kézikönyv" (hungarian coronavirus manual), and as such, are considered as standard-of-care. concomitant use of lmwhs can be considered as emerging standard-of-care, and therefore their application is not prohibited. - standard of care treatment planned with chloroquine or hydroxychloroquine. - any clinically significant abnormality identified during pre-study full physical examination, vital signs, laboratory tests and ecg which is deemed by the investigator to be incompatible / inappropriate for study participation. - known hepatitis b, c, or hiv infection. - a current or recent history of drug or substance abuse, including alcohol (> 14 units per week), within 3 months prior to screening (one unit of alcohol equals ½ pint [285 ml] of beer or lager, one glass [125 ml] of wine, or one shot [25 ml] of spirits) - patients who regularly consume more than 4 cups daily of beverage containing caffeine - current strong smoker as defined by smoking over 10 cigarettes a day, or its equivalent - positive pregnancy test result for women with childbearing potential at screening - women who are pregnant or nursing, or who are planning to get pregnant within 3 months after the last dose of study drug - a history of allergy, intolerance or sensitivity to fluvoxamine or any component of the study drug formulation - closed-angle glaucoma - patients who are assessed as at risk for suicidal intent during screening by psychiatric evaluation (including c-ssrs questionnaire). a score of 15 or higher on the phq-9 depression scale at screening. - have undergone surgery or have donated blood within 12 weeks prior to the start of the study - a history of bleeding diathesis or other bleeding disorders - participated in any clinical trial involving an investigational drug or investigational device within 1 month preceding study entry, or within 5 terminal half-life of the investigational drug of this previous study - a history of or present malignancy, with the exception of resected basal cell carcinoma or squamous cell carcinoma of the skin, or resected cervical intraepithelial neoplasia. prohibited concomitant medications: - co-administration of fluvoxamine with monoamine oxidase inhibitors (maoi), including methylene blue (intravenous dye) and linezolid (an antibiotic which is a reversible non-selective maoi) - co-administration of thioridazine, mesoridazine, pimozide, terfenadine, astemizole, or cisapride with fluvoxamine; each of these drugs alone produces prolongation of the qtc interval, which is associated with serious ventricular arrhythmias, such as torsade de pointes-type arrhythmias and sudden death - co-administration of tizanidine and fluvoxamine - co-administration of fluvoxamine with ramelteon - co-administration of fluvoxamine with chloroquine or hydroxychloroquine - co-administration of morphine, or other opioids.

- mild covid-19 at randomisation (each of the followings met): no dyspnoea, respiratory rate < 22 / min, no need for oxygen supplementation, no pneumonia on medical imaging - severe covid-19 at randomisation: respiratory distress - respiratory rate ≥ 30/min, oxygen saturation at rest ≤ 93%, pulmonary infiltrates occupy > 50% of the lung-fields - critical covid-19 at randomisation: acute respiratory distress, requiring mechanical ventilation, radiomorphology of ards, shock, including septic shock, other organ dysfunction necessitating icu admission - high-risk patient for progression of covid-19, as defined by having a calculated pneumonia port-score of > 90 - concomitant or previous administration of any experimental, non-established covid-19 therapy, either in off-label indication (of a registered medicinal product) or as a non-registered drug candidate in a clinical trial setting or compassionate use program (or equivalents thereof), except therapies recommended by the "magyar koronavírus kézikönyv" (hungarian coronavirus manual), and as such, are considered as standard-of-care. concomitant use of lmwhs can be considered as emerging standard-of-care, and therefore their application is not prohibited. - standard of care treatment planned with chloroquine or hydroxychloroquine. - any clinically significant abnormality identified during pre-study full physical examination, vital signs, laboratory tests and ecg which is deemed by the investigator to be incompatible / inappropriate for study participation. - known hepatitis b, c, or hiv infection. - a current or recent history of drug or substance abuse, including alcohol (> 14 units per week), within 3 months prior to screening (one unit of alcohol equals ½ pint [285 ml] of beer or lager, one glass [125 ml] of wine, or one shot [25 ml] of spirits) - patients who regularly consume more than 4 cups daily of beverage containing caffeine - current strong smoker as defined by smoking over 10 cigarettes a day, or its equivalent - positive pregnancy test result for women with childbearing potential at screening - women who are pregnant or nursing, or who are planning to get pregnant within 3 months after the last dose of study drug - a history of allergy, intolerance or sensitivity to fluvoxamine or any component of the study drug formulation - closed-angle glaucoma - patients who are assessed as at risk for suicidal intent during screening by psychiatric evaluation (including c-ssrs questionnaire). a score of 15 or higher on the phq-9 depression scale at screening. - have undergone surgery or have donated blood within 12 weeks prior to the start of the study - a history of bleeding diathesis or other bleeding disorders - participated in any clinical trial involving an investigational drug or investigational device within 1 month preceding study entry, or within 5 terminal half-life of the investigational drug of this previous study - a history of or present malignancy, with the exception of resected basal cell carcinoma or squamous cell carcinoma of the skin, or resected cervical intraepithelial neoplasia. prohibited concomitant medications: - co-administration of fluvoxamine with monoamine oxidase inhibitors (maoi), including methylene blue (intravenous dye) and linezolid (an antibiotic which is a reversible non-selective maoi) - co-administration of thioridazine, mesoridazine, pimozide, terfenadine, astemizole, or cisapride with fluvoxamine; each of these drugs alone produces prolongation of the qtc interval, which is associated with serious ventricular arrhythmias, such as torsade de pointes-type arrhythmias and sudden death - co-administration of tizanidine and fluvoxamine - co-administration of fluvoxamine with ramelteon - co-administration of fluvoxamine with chloroquine or hydroxychloroquine - co-administration of morphine, or other opioids.