for people ages 18 years and up (full criteria)
Healthy Volunteers
healthy people welcome
study started
estimated completion



The study will evaluate the efficacy of Ad26.COV2.S in the prevention of molecularly confirmed moderate to severe/critical COVID-19, as compared to placebo, in adult participants.

Official Title

A Randomized, Double-blind, Placebo-controlled Phase 3 Study to Assess the Efficacy and Safety of Ad26.COV2.S for the Prevention of SARS-CoV-2-mediated COVID-19 in Adults Aged 18 Years and Older


Participants With or Without Stable Co-morbidities Associated With Progression to Severe COVID-19 at Different Stages of the Protocol, Prevention, Vaccine, COVID-19, Ad26.COV2.S


You can join if…

Open to people ages 18 years and up

  • Contraceptive (birth control) use should be consistent with local regulations regarding the acceptable methods of contraception for those participating in clinical studies
  • All participants of childbearing potential must: have a negative highly sensitive urine pregnancy test at screening; and have a negative highly sensitive urine pregnancy test immediately prior to each study vaccine administration
  • Participant agrees to not donate bone marrow, blood, and blood products from the first study vaccine administration until 3 months after receiving the last dose of study vaccine
  • Must be willing to provide verifiable identification, has means to be contacted and to contact the investigator during the study
  • Must be able to read, understand, and complete questionnaires in the electronic clinical outcome assessment (eCOA) (that is, the coronavirus disease-2019 [COVID 19] signs and symptoms surveillance question, the e-Diary, and the electronic patient-reported outcomes (ePROs). Note: Participants with visual impairment are eligible for study participation and may have caregiver assistance in completing the electronic clinical outcome assessment (eCOA) questionnaires

You CAN'T join if...

  • Participant has a clinically significant acute illness (this does not include minor illnesses such as diarrhea or mild upper respiratory tract infection) or temperature greater than or equal to (>=) 38.0 degree Celsius (100.4-degree Fahrenheit) within 24 hours prior to the planned first dose of study vaccine; randomization at a later date is permitted at the discretion of the investigator and after consultation with the sponsor
  • Participant received or plans to receive: (a) licensed live attenuated vaccines - within 28 days before or after planned administration of study vaccine ; and (b) other licensed (not live) vaccines - within 14 days before or after planned administration of study vaccine
  • Participant previously received a coronavirus vaccine
  • Participant received an investigational drug (including investigational drugs for prophylaxis of COVID-19) within 30 days or used an invasive investigational medical device within 30 days or received investigational immunoglobulin (Ig) or monoclonal antibodies within 3 months, or received convalescent serum for COVID-19 treatment within 4 months or received an investigational vaccine (including investigational Adenoviral-vectored vaccines) within 6 months before the planned administration of the first dose of study vaccine or is currently enrolled or plans to participate in another investigational study during the course of this study


  • UCSD Antiviral Research Center AVRC
    San Diego California 92103 United States
  • VA Medical Center
    San Francisco California 94121-1545 United States
  • Anthony Mills Medical, Inc
    Los Angeles California 90069 United States
  • Wr-McCr, Llc
    San Diego California 92108 United States
  • Anaheim Clinical Trials, LLC
    Anaheim California 92801 United States
  • Ark Clinical Research
    Long Beach California 90806 United States
  • Stanford University Medical Center
    Palo Alto California 94304 United States


in progress, not accepting new patients
Start Date
Completion Date
Janssen Vaccines & Prevention B.V.
Phase 3 COVID-19 Research Study
Study Type
About 44325 people participating
Last Updated