There is an urgent need to explore therapeutic options for SARS-CoV-2 in order to face the pandemic. The selected intervention was based on that zafirlukast will have dual effect; first it will block the virus replication through inhibiting the COVID19 helicase that is involved in virus replication and secondly by reducing the inflammation through antagonizing the leukotriene receptor.

The purpose of this study is to evaluate the clinical efficacy and safety of Leukotriene receptor antagonist in the treatment of moderate cases of COVID-19 patients.

Inclusion Criteria:

1. Age of 18 years or above
2. Diagnosed with COVID-19 by PCR confirmed SARS-coV-2 viral infection.
3. Able to sign the consent form and agree to clinical samples collection
4. Moderate symptomatic COVID-19 patients, (any or all of the followings: fever or cough or SOB)
5. Admitted to the hospital (outside the ICU)
6. Patients had to be enrolled within 10 days of symptoms onset.
7. willingness to comply with all study procedures and availability for the duration of the study

Exclusion Criteria:

1. Asthmatic patient using antiasthma medications
2. Being in the hospital or in home isolation for more than 72 hours before the start of the study drug.
3. Known sensitivity/allergy to the study drug
4. Pregnancy
5. Patient refused
6. Chronic liver disease
7. Severe mental disorder
8. Unstable patients requiring ICU admission
9. Participating in other clinical trial