VICO Trial

Full title: VICO Trial: A multi center randomized open label trial on the safety and efficacy of chloroquine for the treatment of hospitalized adults with laboratory confirmed SARS-CoV-2 infection in Vietnam

Funder: Viet Nam Ministry of Health and OUCRU (Wellcome funding)

Principal Investigator: Jeremy Day

Location of research: Vietnam

COVID-19 is a respiratory disease caused by a novel coronavirus (SARS-CoV-2) and causes substantial morbidity and mortality. There is currently no vaccine to prevent COVID-19 or therapeutic agent to treat COVID-19. This clinical trial is designed to evaluate chloroquine as a potential therapeutic for the treatment of hospitalised people with COVID-19. We hypothesise that chloroquine slows viral replication in patients with COVID-19, attenuating the infection, and resulting in more rapid declines of viral load in throat/nose swabs. This viral attenuation should be associated with improved patient outcomes.

Study design

The study is an open label, randomised, controlled trial with 2 parallel arms of standard of care (control arm) versus standard of care with 10 days of chloroquine (intervention arm) with a loading dose over the first 24 hours, followed by 300mg base orally once daily for 9 days. The study will recruit patients in three sites in Ho Chi Minh City, Viet Nam: the Hospital for Tropical Diseases, the Cu Chi Field Hospital, and the Can Gio COVID-19 hospital. The primary endpoint is the time to viral clearance from throat/nose swab defined as the time following randomization until the midpoint between the last positive and the first of the negative throat/nose swabs. Viral presence will be determined using RT-PCR to detect SARS-CoV-2 RNA. Prior to the randomization stage, there will be a 10-patient prospective observational pilot study following the same entry and exclusion criteria as for the randomized trial, undergoing the same procedures, to deliver preliminary feasibility and safety data.


The results of the study will add to the evidence-based guidelines for management of COVID-19. Given the enormous experience of its use in malaria chemoprophylaxis, excellent safety and tolerability profile, and its very low cost, if proved effective then chloroquine would be a readily deployable and affordable treatment for patients with COVID-19.

Outputs to date

The trial protocol has been published in Wellcome Open Research: