The aim of the study is to evaluate whether the therapy with chloroquine phosphate (CQ, in combination with telemedical approach) in addition to standard care is effective and safe in reducing composite endpoint of COVID-19-related hospitalization or all cause death, in ambulatory patients with SARS-SoV-2 infection at particular risk of serious complications due to advanced age and/or comorbid conditions (in comparison with subjects not treated with CQ but receiving standard care and supervised telemedically).

Until now there are no evidence-based, good-quality data from sufficiently powered clinical trials supporting the use of any antiviral medicines or immunomodulatory therapies in the management or prophylaxis of COVID-19; however there are currently being initiated studies in Europe and U.S., and a few registered studies are ongoing in China. Currently two groups of medicines are hypothesized to be effective therapeutic options in COVID-19: (1) classical antiviral drugs interfering with pathogen dissemination / replication, and (2) compounds inhibiting host inflammatory reactions, especially (and potentially selectively) in respiratory tract / system (cytokine inhibitors and specific antibodies). Special hopes are placed in quinoline derivatives such as chloroquine (CQ), based on some unpublished data from China and a few experiments in vitro. CQ is an old antimalarial drug that has been used for more than 50 years in the therapy and prevention of this parasitosis. Anti-inflammatory features of quinolone derivatives such as CQ or hydroxychloroquine have also been used in rheumatology (for the therapy of lupus erythematosus or rheumatoid arthritis) due to the inhibition of the production of proinflammatory cytokines. The effectiveness (and safety) of CQ in COVID-19 has not been investigated in sufficiently powered RCTs until now.

INCLUSION CRITERIA

1. age >=60 years OR age 18-59 years with one of the following conditions:

   1. chronic lung disease
   2. chronic cardiovascular disease
   3. diabetes
   4. malignancy diagnosed within 5 years prior to enrollment
   5. history of chronic kidney disease
   6. atrial fibrillation
   7. past haemorrhagic stroke, ischemic stroke or transient CNS ischemia
   8. obesity defined as BMI ≥ 30 kg / m2
   9. 10-year risk of fatal cardiovascular disease

2. SARS-CoV-2 infection confirmed in RT-PCR (nasopharyngeal swab)

3. Hospitalization not required based on clinical judgement

4. Ability to participate in telemedical care

EXCLUSION CRITERIA

1. Lack of written informed consent
2. Possible failure to comply with the protocol
3. Chloroquine, hydroxychloroquine therapy within 30 days prior to enrollment
4. Antiviral therapy within 14 days prior to enrollment
5. Contraindications to chloroquine (pregnancy, breast-feeding, severe renal insufficiency, amiodarone therapy, alcohol disease, haematological disorders, epilepsia, porphyria, liver disease/cirrhosis, retinopathy, fainting/syncope, myasthenia)
6. Hypersensitivity to chloroquine or drug excipients
7. HIV infection
8. Other relevant circumstances/conditions based on clinical judgement
9. Concurrent participation in another interventional clinical trial