Janssen’s Single-Shot COVID-19 Vaccine Gets Emergency Use Authorization

The EUA was based on data from the randomized, double-blind, placebo-controlled ENSEMBLE trial.

The Food and Drug Administration (FDA) has granted Emergency Use Authorization (EUA) to Janssen’s single-dose vaccine for active immunization to prevent coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in individuals 18 years of age and older.

The Janssen COVID-19 vaccine is a replication-incompetent adenovirus type 26 vectored vaccine encoding a stabilized variant of the SARS-CoV-2 S protein. The EUA is based on data from the randomized, double-blind, placebo-controlled ENSEMBLE trial (ClinicalTrials.gov: NCT04505722), which included over 44,000 adults in Argentina, Brazil, Chile, Colombia, Mexico, Peru, South Africa, and the United States (US). Participants were randomly assigned to receive the Janssen COVID-19 vaccine or placebo intramuscularly as a single dose.

An interim analysis (based on 43,783 participants) showed that the vaccine was 66% effective in preventing moderate to severe COVID-19 at least 28 days post-vaccination (there were 66 cases in the vaccine group and 193 cases in the placebo group). Onset of protection was observed as early as day 14. The vaccine was also found to be 85% effective in preventing severe/critical disease and demonstrated complete protection against COVID-19 related hospitalization and death at 28 days post vaccination.

Moreover, the vaccine demonstrated complete protection against COVID-19 related hospitalization and death at 28 days post vaccination. There were no reported COVID-19-related deaths in the vaccine arm compared with 7 in the placebo arm, as of February 5, 2021.

“After a thorough analysis of the data, the FDA’s scientists and physicians have determined that the vaccine meets the FDA’s expectations for safety and effectiveness appropriate for the authorization of a vaccine for emergency use,” said Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research.

Additional data from the trial will be collected and used to prepare the Biologics License Application for full regulatory approval, which is expected to be submitted to the FDA in 2021. Following the announcement of the EUA, the Centers for Disease Control and Prevention (CDC)’s Advisory Committee on Immunization Practices (ACIP) voted to recommend the use of the vaccine.

The vaccine is supplied as a suspension in multi-dose vials and is estimated to remain stable for 2 years at -4°F (-20°C), and a maximum of 3 months at routine refrigeration at temperatures of 36-46°F (2 to 8°C). The Company plans to deliver 100 million doses to the US through the first half of 2021, with 20 million doses expected in March; allocation and distribution will be managed by the US government.

As part of the EUA, a summary of instructions and important safety information is detailed in a fact sheet for health care providers. Following administration, adverse reactions that have been reported in clinical trials included injection site pain/erythema/swelling, headache, fatigue, myalgia, nausea, and fever. Patients who receive the vaccine should be monitored for the occurrence of immediate adverse reactions according to CDC guidelines.


1.      Johnson & Johnson COVID-19 Vaccine authorized by US FDA for Emergency Use – first single-shot vaccine in fight against global pandemic. [press release]. February 27, 2021.

2.      Johnson & Johnson announces US CDC advisory committee recommends first single-shot COVID-19 vaccine for adults 18 and older in US [press release]. February 28, 2021.

3.      FDA issues Emergency Use Authorization for third COVID-19 vaccine. [press release]. February 27, 2021.