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ENSEMBLE COVID-19 Clinical Trial

About this study

This clinical trial, the ENSEMBLE trial, was led by St. Jude and the University of Tennessee Health Science Center. Adults in the Memphis, Tenn. area who enrolled in the study received a COVID-19 prevention vaccine or a placebo.

The study closed to enrollment on Dec. 17, 2020.  On Feb. 21, 2021, the U.S. Food and Drug Administration issued an Emergency Use Authorization (EUA) for the single-dose COVID-19 vaccine in people 18 years of age and older.

The study showed the vaccine studied in the ENSEMBLE trial was 85 percent effective in preventing severe disease and preventing COVID-related hospitalization and death, beginning 28 days after vaccination.

The above information is intended to provide only a basic description about a research protocol that may be currently active at St. Jude. The details made available here may not be the most up-to-date information on protocols used by St. Jude. To receive full details about a protocol and its status and or use at St. Jude, a physician must contact St. Jude directly.


Full 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

Study goal:

The ENSEMBLE trial tested the safety and effectiveness of a single-dose, investigational COVID-19 vaccine in adults.

Clinical trials categories:

Infectious Diseases COVID-19

For physicians and researchers

Patients accepted to St. Jude must be referred by a physician or other qualified medical professional. Learn how St. Jude can partner with you to care for your patient.


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