Clinical trial Recruiting at 200 sites Phase 3 Interventional Ages 18 and up

Using Molnupiravir to Prevent Severe COVID-19 in High-Risk Individuals

Official title: A Phase 3, Randomized, Placebo-Controlled, Double-Blind Clinical Study to Evaluate the Efficacy and Safety of Molnupiravir (MK-4482) in Non-Hospitalized Adults With COVID-19 at High Risk for Disease Progression

Run by Merck Sharp & Dohme LLC · NCT06667700 · Data updated 2026-11-12

This study is testing if the medication molnupiravir can help prevent severe COVID-19 in high-risk individuals who have recently shown symptoms of the virus.

Quick facts

PhasePhase 3
Study typeInterventional
Ages18 Years and up
SexAll
Enrollment3082 (estimated)
SponsorMerck Sharp & Dohme LLC
Industry-sponsored
Locations229 sites (Cullman, Alabama and 228 other locations)
StatusRecruiting
StartedDecember 2, 2024
Main results expectedJanuary 26, 2031
Study endsJanuary 26, 2031
Registry record updatedNovember 6, 2026
Trial IDNCT06667700 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates include adults aged 18 and older who have recently tested positive for COVID-19 and exhibit symptoms, particularly those with high-risk factors such as advanced age or immunocompromised status.

Probably not a fit

Patients who are not at high risk for severe illness from COVID-19 or those who do not have recent symptoms may not benefit from this study.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This clinical study investigates the effectiveness of molnupiravir, a medication designed to inhibit the replication of the COVID-19 virus, in preventing severe illness among individuals at high risk for complications from the disease. Participants must be at least 18 years old and have documented SARS-CoV-2 infection with symptoms that began within the last four days. The study compares the outcomes of those receiving molnupiravir to those receiving a placebo to determine if the treatment can significantly reduce the severity of COVID-19 symptoms. The focus is on individuals with specific health conditions or characteristics that increase their risk of severe illness.

Why it matters

Potential benefit: If successful, this treatment could significantly reduce the incidence of severe COVID-19 illness in high-risk patients.

How similar studies have gone: Other studies have shown promise with antiviral treatments for COVID-19, making this approach both relevant and potentially impactful.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria

The main inclusion criteria include but are not limited to the following:

* Is an individual of any sex/gender, ≥18 years of age
* Has documentation of SARS-CoV-2 infection with sample collection ≤4 days prior to randomization
* Has initial onset of signs/symptoms attributable to COVID-19 for ≤4 days prior to the day of randomization and ≥2 of the following signs/symptoms attributable to COVID-19 on the day of randomization: cough, sore throat, nasal congestion, shortness of breath or difficulty breathing with exertion, muscle or body aches, fatigue, fever \>38.0°C or chills, nausea or vomiting or diarrhea, change in sense of smell or change in sense of taste, or headache
* Has ≥1 of the following characteristics or medical conditions associated with the highest risk of severe illness from COVID-19:

  * Advanced age of ≥75 years of age
  * Immunocompromised
  * Neurocognitive or physical disability
  * Has ≥3 characteristics or medical conditions which increase the risk of severe illness due to COVID-19 (e.g., chronic lung disease, obesity with body mass index (BMI) ≥35, diabetes)
* Is unable or unwilling to receive treatment with nirmatrelvir/ritonavir (NMV/r) due to 1 or more of the following:

  * Is receiving drug(s) highly dependent on cytochrome P450 3A (CYP3A) for clearance and for which elevated concentrations are associated with serious and/or life-threatening consequences or drug(s) with a clinically significant drug-drug interaction for which co-administration is not possible
  * Is receiving potent CYP3A inducers where significantly reduced nirmatrelvir or ritonavir plasma concentrations may be associated with the potential for loss of virologic response and possible resistance
  * Has severe hepatic impairment
  * Has experienced prior adverse reactions or hepatotoxicity to NMV/r that would preclude future use
  * Has known or suspected NMV/r resistance
  * Has uncontrolled HIV infection
  * NMV/r is not approved/authorized in the participant's country or it is not accessible to participant (e.g., drug shortage)
  * Is unwilling to receive treatment with NMV/r

Inclusion note: Participants may receive remdesivir as standard of care in addition to molnupiravir or placebo. If remdesivir is available and clinically appropriate per local clinical practice, investigators will aim to ensure that those who are most vulnerable to severe COVID-19 receive timely access to remdesivir as standard of care on this study.

Exclusion Criteria

The main exclusion criteria include but are not limited to the following:

* Is currently hospitalized or is expected to need hospitalization for COVID-19 imminently
* Has received or plans to receive SARS-CoV-2 directed oral antivirals or monoclonal antibodies for current episode of COVID-19 (other than study intervention and, if applicable, remdesivir as standard of care)
* Has ≥1 of the following signs/symptoms that are attributable to severe or critical COVID-19:

  * Shortness of breath at rest
  * Respiratory rate ≥30 breaths per minute
  * Heart rate ≥125 beats per minute
  * Peripheral oxygen saturation (SpO2) ≤93% on room air or on supplemental oxygen for a reason other than COVID-19 which has not increased since onset of COVID-19 signs/symptoms
  * New or increasing need for supplemental oxygen: receiving \>4 liters/minute supplemental oxygen due to COVID-19 OR on supplemental oxygen for a reason other than COVID-19 which has increased due to COVID-19
* Has received a COVID-19 vaccine within 30 days prior to randomization
* Has a history of confirmed influenza, respiratory syncytial virus (RSV), or SARS-CoV-2 infection (with or without symptoms; excluding current infection) within 30 days prior to randomization
* Has known or suspected hypersensitivity to active or inactive ingredients of molnupiravir

Where it's running

  • Helios Clinical Research ( Site 3826)
    Paradise Valley, Arizona, United States
    Recruiting
  • Clinica de Salud del Valle de Salinas ( Site 3825)
    Castroville, California, United States
    Recruiting
  • Pacific Clinical Studies ( Site 3827)
    Los Alamitos, California, United States
    Recruiting
  • Valley Clinical Trials, Inc. ( Site 3707)
    Northridge, California, United States
    Recruiting
  • FOMAT Medical Research ( Site 3720)
    Oxnard, California, United States
    Recruiting
  • Paradigm Clinical Research, LLC ( Site 3785)
    San Diego, California, United States
    Recruiting
Show 44 more locations
  • Optimus Medical ( Site 3817)
    San Francisco, California, United States
    Recruiting
  • Millennium Clinical Trials ( Site 3758)
    Westlake Village, California, United States
    Recruiting
  • Paradigm Clinical Research Centers, Inc ( Site 3718)
    Wheat Ridge, Colorado, United States
    Recruiting
  • Encore Medical Research of Boynton Beach ( Site 3701)
    Boynton Beach, Florida, United States
    Recruiting
  • Prestige Clinical Research Center ( Site 3722)
    Coral Gables, Florida, United States
    Recruiting
  • Prestige Clinical Research ( Site 3830)
    Homestead, Florida, United States
    Recruiting
  • Accel Research Sites Network - St. Pete-Largo Clinical Research Unit ( Site 3779)
    Largo, Florida, United States
    Recruiting
  • Clinical Site Partners, LLC dba Flourish Research ( Site 3717)
    Leesburg, Florida, United States
    Recruiting
  • Southern Clinical Research ( Site 3773)
    Miami, Florida, United States
    Recruiting
  • Florida Pharmaceutical Research and Associates ( Site 3763)
    Miami, Florida, United States
    Recruiting
  • Bio-Medical Research LLC ( Site 3804)
    Miami, Florida, United States
    Recruiting
  • Miami Clinical Research ( Site 3729)
    Miami, Florida, United States
    Recruiting
  • Reed Medical Research ( Site 3761)
    Miami, Florida, United States
    Recruiting
  • Palm Springs Community Health Center ( Site 3757)
    Miami Lakes, Florida, United States
    Recruiting
  • Panax Clinical Research ( Site 3803)
    Miami Lakes, Florida, United States
    Recruiting
  • Indago Research and Health Center Inc ( Site 3714)
    Miami Lakes, Florida, United States
    Recruiting
  • Combined Research Orlando Phase I-IV ( Site 3797)
    Orlando, Florida, United States
    Recruiting
  • CDC Research Institute ( Site 3716)
    Port Saint Lucie, Florida, United States
    Recruiting
  • New Tampa Health ( Site 3764)
    Tampa, Florida, United States
    Recruiting
  • Clinical Research Trials of Florida ( Site 3703)
    Tampa, Florida, United States
    Recruiting
  • Precision Research Center ( Site 3704)
    Tampa, Florida, United States
    Recruiting
  • Renew Health Clinical Research ( Site 3760)
    Snellville, Georgia, United States
    Recruiting
  • Rush University Medical Center ( Site 3748)
    Chicago, Illinois, United States
    Recruiting
  • Duly Health and Care ( Site 3799)
    Lombard, Illinois, United States
    Recruiting
  • University of Louisville School of Medicine ( Site 3706)
    Louisville, Kentucky, United States
    Recruiting
  • Annapolis Internal Medicine - CCT Research ( Site 3700)
    Annapolis, Maryland, United States
    Recruiting
  • Kur Research - Columbia Medical ( Site 3767)
    Columbia, Maryland, United States
    Recruiting
  • Henry Ford St John TM Center for Infectious Disease Research ( Site 3766)
    Grosse Pointe Woods, Michigan, United States
    Recruiting
  • Mankato Clinic ( Site 3842)
    Mankato, Minnesota, United States
    Recruiting
  • SKY Integrative Medical Center/SKYCRNG ( Site 3740)
    Ridgeland, Mississippi, United States
    Recruiting
  • Nevada Health Centers ( Site 3840)
    Carson City, Nevada, United States
    Recruiting
  • WR-CRCN, LLC ( Site 3818)
    Las Vegas, Nevada, United States
    Recruiting
  • Saint Michael's Medical Center ( Site 3808)
    Newark, New Jersey, United States
    Recruiting
  • Weill Cornell Medical College ( Site 3814)
    New York, New York, United States
    Recruiting
  • Prime Global Research ( Site 3731)
    The Bronx, New York, United States
    Recruiting
  • OnSite Clinical Solutions ( Site 3784)
    Charlotte, North Carolina, United States
    Recruiting
  • Monroe Biomedical Research ( Site 3732)
    Monroe, North Carolina, United States
    Recruiting
  • IMA Clinical Research Mount Airy ( Site 3745)
    Mount Airy, North Carolina, United States
    Recruiting
  • Helios Clinical Research - JAC ( Site 3833)
    Jackson, Tennessee, United States
    Recruiting
  • Javara - Privia Medical Group Gulf Coast - The Woodlands HWH ( Site 3837)
    Conroe, Texas, United States
    Recruiting
  • South Texas Clinical Research ( Site 3815)
    Corpus Christi, Texas, United States
    Recruiting
  • Houston Methodist Hospital ( Site 3800)
    Houston, Texas, United States
    Recruiting
  • MD Anderson ( Site 3843)
    Houston, Texas, United States
    Recruiting
  • Andres Garcia Zuniga, M.D., P.A. ( Site 3782)
    Laredo, Texas, United States
    Recruiting

+179 more sites. See ClinicalTrials.gov for the full list.

Study contacts

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How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.