The Prevent Severe COVID-19 (PRESECO) Study

Inclusion Criteria:

- Adults age 18 or older

- Tested positive for SARS-CoV-2 by RT-PCR assay using a respiratory tract sample
(either nasopharyngeal swab OR oropharyngeal swab OR nasal aspirate OR
tracheobronchial aspirate OR saliva) collected within 72 hours of randomization

- Stated willingness to give their written informed consent to participate in the study

- Stated willingness to comply with all study procedures and availability for the
duration of the study

- Males must be sterile, OR agree not to donate semen AND agree to strictly adhere to
contraceptive measures during the study and for 7 days following the last dose of
study medication

- Females must be unable to bear children, OR ensure that their male partner is
incapable of fathering a child, OR, if of childbearing potential will strictly adhere
to contraceptive measures during the study and for seven days following the last dose
of study medication

- Females must agree to stop breast-feeding prior to first dose of study drug and
through seven days after completing therapy

- Females must have a negative pregnancy test at screening

- Ability to take oral medication and be willing to adhere to the favipiravir/placebo
regimen

- Subject has access to a smart phone, tablet, or PC

- Minimal baseline severity score for COVID-19-related symptoms: at least two symptoms
with a score of 2 or higher. COVID-19-related symptoms (excluding changes in the sense
of taste or smell) include:

- stuffy or runny nose

- sore throat

- shortness of breath

- cough

- lack of energy or tiredness

- muscle or body aches

- headache

- chills or shivering

- feeling hot or feverish

- nausea

- diarrhea

- vomiting

Exclusion Criteria:

- O2 saturation <94%

- Shortness of breath at rest

- Heart rate ≥ 125 per minute

- COVID-19 symptoms first presented >5 days prior to randomization

- Requirement for hospitalization at the time of enrollment

- Participation in another trial or use of any experimental treatment for COVID-19

- Treatment with high steroid dose i.e. >30 mg/day prednisolone equivalent (excluding
stable chronic treatment) or remdesivir or anyone receiving SARS-CoV-2 monoclonal
antibodies within 3 months prior to enrollment

- Known sepsis or organ dysfunction/ failure

- Known infection with a respiratory virus other than SARS-CoV2 (e.g. Influenza) or any
known bacterial infection (affecting the respiratory system or any other system)

- Inability to adhere to study requirements

- For premenopausal women: unwilling or unable to use effective birth control measures

- Known allergy to favipiravir

- Known end-stage kidney disease or requiring hemodialysis or continuous ambulatory
peritoneal dialysis (CAPD)

- Known liver impairment greater than Child-Pugh A

- Psychiatric illness that is not well controlled (defined as stable on a regimen for
more than one year).

- Known elevated uric acid levels in the past year or taking uric acid lowering
medications (allopurinol, febuxostat)

- History of hereditary xanthinuria or history of xanthine urolithiasis.

- History of gout or actively being treated for gout.

- Current use of the following medications, which cannot be discontinued for the
duration of the study: pyrazinamide, hydralazine, more than 3000 mg of acetaminophen
per day.