A Field Trial to examine the effect of hydroxychloroquine prophylaxis in preventing the sever forms of COVID-19 infection in asymptomatic healthcare workers (A double blind placebo controlled study)

Efficacy of hydroxychloroquine in prevention of sever forms of COVID-19 Disease will be studied.

Randomized placebo controlled field trial, 400 participants

This study is a double blind placebo controlled field trial on 400 participants. Using balanced blocked randomization people are randomly assigned to one of the two groups.The subjects in the intervention group will take 800 mg hydroxychloroquine tablets, ie four 200mg tablets, in two separate doses on the same day in the first week and then 400 mg, ie 2 tablets weekly in a single dose for 7 weeks. The control group will take a placebo in the same order. Tablets should be given after meal. Both groups will be followed for 10 weeks. The participants who caught COVID-19 during the study period will be followed until the end of the disease to assess the outcomes.

Inclusion criteria: Healthcare workers and students of Islamic Azad University Tehran Medical Branch (IAUTMU) affiliated hospitals Age 18-70 y and no symptoms of COVID-19 at the time of registration Desire to participate in the study and filling out the consent form Exclusion criteria: Contraindications for hydroxychloroquine including allergy to hydorxychloroquine, G6PD, Long QT Syndrome, Porphyria, rethinopathy Acute symptoms of COVID-19 at the time of registration COVID-19 diagnosis within the past 3 months Pregnancy Sever kidney or liver disease HIV, AIDS Systemic lupus erythematosus, rheumatoid arthritis Active cancer

Intervention Group (200 people) will get hydroxychloroquine and Control Group (200 people) will get placebo as per study protocol and will have follow-up for 10 weeks.

1.Sever forms of COVID-19 needing admission to medical ward 2. ICU admission 3. mortality 4.mild forms of COVID-19

Using Balanced- Blocked Randomization, subjects are randomly assigned to one of the two control and intervention groups. The computerization process is done by an epidemiologist and a statistician. Individuals will enter the assigned groups based on their entry sequence. For the drug under study placebo is made by the same pharmaceutical company. Participants in the study are blind to receive actual medication. People who measure variables during research are also blind about how people belong to the groups ( two way blinding).

This study is a double blind field trial. Hydroxychloroquine and placebo are made by Tehran Darou pharmaceutical company in uniform packages with defined codes. Drug and placebo will be dispensed by a third party. The participants in the study are blind to receive actual medication. People who measure the variables and fill out the questionnaires during the research are also blind about how people belong to the groups (two way blinding).