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.