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. 2021 Nov 1;16(11):725–739. doi: 10.2217/fvl-2021-0199

A plain language summary of how well the single-dose Janssen vaccine works and how safe it is

J Sadoff 1, F Struyf 2, M Douoguih 1,*
PMCID: PMC8587777  PMID: 34824596

Abstract

This is a summary of a publication about the ENSEMBLE trial of the Janssen Ad26.COV2.S vaccine against COVID-19, which was published in the New England Journal of Medicine in April 2021. The ENSEMBLE study started in September 2020 and is still ongoing.

The study compared the effectiveness of the vaccine to a placebo in 43,783 adults from Latin America, South Africa, and the United States. Of those, 19,630 got a single dose of the vaccine.

Compared to the placebo, the vaccine prevented:

  • 66.9% of moderate to severe–critical COVID-19 cases after 14 days

  • 66.1% of moderate to severe–critical COVID-19 cases after 28 days

  • 85.4% of severe COVID-19 cases after 28 days

  • 100% of people with severe COVID-19 from needing to go to hospital for treatment

None of the vaccinated participants died from COVID-19. There were 5 people who got the placebo who died from COVID-19.

The vaccine was similarly effective in people from all age groups and different countries, including South Africa, where most cases were caused by the beta variant of the virus that originated there. The people in the study who got the vaccine who went on to get COVID-19 generally had milder and fewer symptoms than those who got the placebo. In most people, the vaccine started working after about 2 weeks.

After receiving the vaccine, some people experienced pain at the injection site, headache, tiredness, muscle pain, and nausea. In most cases, these were mild and went away within a few days. Serious side effects were very rare. Blood clots, seizures, and tinnitus were very rare but were more common in the people who got the vaccine than in those who got the placebo. At the time of the study, it was not clear if these were caused by the vaccine or not.

ClinicalTrials.gov NCT number: NCT04505722.

Keywords: : clinical trial, coronavirus, COVID-19 vaccines, plain language summary , vaccine development, vaccine efficacy, vaccine


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Link to original article here.

Acknowledgments

The authors thank all the participants in this trial, the staff members at the trial locations, the members of the data and safety monitoring board, all the investigators at the clinical sites, the authors of the primary manuscript (Glenda Gray, An Vandebosch, Vicky Cardenas, Georgi Shukarev, Beatriz Grinsztejn, Paul A Goepfert, Carla Truyers, Hein Fennema, Bart Spiessens, Kim Offergeld, Gert Scheper, Kimberly L Taylor, Merlin L Robb, John Treanor, Dan H Barouch, Jeffrey Stoddard, Martin F Ryser, Mary A Marovich, Kathleen M Neuzil, Lawrence Corey, Nancy Cauwenberghs, Tamzin Tanner, Karin Hardt, Javier Ruiz‑Guinazu, Mahieu Le Gars, Hanneke Schuitemaker, and Johan Van Hoof), the COV3001 study team (Richard Gorman, Carmen A Paez, Edith Swann, James Kublin, Simbarashe G Takuva, Alex Greninger, Pavitra Roychoudhury, Robert W Coombs, Keith R Jerome, Flora Castellino, Xiaomi Tong, Corrina Pavetto, Teletha Gipson, Tina Tong, Marina Lee, James Zhou, Michael Fay, Kelly McQuarrie, Chimeremma Nnadi, Obiageli Sogbetun, Nina Ahmad, Ian De Proost, Cyrus Hoseyni, Paul Coplan, Najat Khan, Peter Ronco, Dawn Furey, Jodi Meck, Johan Vingerhoets, Boerries Brandenburg, Jerome Custers, Jenny Hendriks, Jarek Juraszek, Marit de Groot, Griet Van Roey, Dirk Heerwegh, and Ilse Van Dromme), and Mary L Greenacre (An Sgriobhadair), Jill E Kolesar and Kurt Kunz (Cello Health Communications/MedErgy) for writing and editorial assistance with the original article (funded by Janssen Global Services), and Kimbra Edwards and Brandis Pickard (CISCRP) and Elizabeth Perdeaux and Sarah Griffiths (Oxford PharmaGenesis) for writing and editorial assistance with this article.

Footnotes

Financial & competing interests disclosure

Sadoff is a full-time employee of Janssen Research & Development, LLC. F Struyf and M Douoguih are both full-time employees of Johnson & Johnson. All the authors hold restricted shares and stock options in Johnson & Johnson as part of their remuneration. The authors have no other relevant affiliations or financial involvement with any organisation or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Open access

This work is licensed under the Attribution-NoDerivatives 4.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nd/4.0/


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