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JAMA Patient Page
March 1, 2021

The Johnson & Johnson Vaccine for COVID-19

Author Affiliations
  • 1Deputy Editor, JAMA
  • 2Associate Editor, JAMA
  • 3Vanderbilt University School of Medicine, Nashville, Tennessee
JAMA. 2021;325(15):1575. doi:10.1001/jama.2021.2927

Johnson & Johnson has developed a vaccine that works differently than the Pfizer and Moderna vaccines and is highly effective for preventing moderate to severe COVID-19.

What Is the Johnson & Johnson Vaccine?

The COVID-19 vaccine from Johnson & Johnson uses existing technology that involves a virus called adenovirus, a common cause of respiratory infections. The DNA in the adenovirus is modified so that it produces a key part of the SARS-CoV-2 virus particle to which the body then develops an immune response. The adenovirus that delivers the SARS-CoV-2 DNA particle cannot multiply, so it does not cause infection. Because this system is based on stable DNA molecules, it does not require ultracold storage, making it easier to distribute.

How Does the Johnson & Johnson Vaccine Differ From Other Available COVID-19 Vaccines?

The Pfizer and Moderna COVID-19 vaccine technology uses genetic material (mRNA) that code for parts of the SARS-CoV-2 virus protein. This mRNA is protected by lipid nanoparticles (fat bubbles) that, when injected, cause a person’s own cells to make pieces of viral particles to which the body develops immunity. Because the genetic material is broken down quickly, it stays in a person’s cells for only a short period of time. For this reason, these vaccines must be kept in very cold environments until they are ready to be given.

How Safe and Effective Is the Johnson & Johnson Vaccine?

Initially, the Johnson & Johnson vaccine was shown to produce antibodies against SARS-CoV-2 in 90% of people who received it after the first dose. The amount of antibodies was greater for those who received 2 doses of the vaccine. Data released by Johnson & Johnson suggest that 1 dose of vaccine was 66% effective in preventing moderate to severe COVID-19 and 100% effective in preventing COVID-19–related hospitalization and death. These data are being reviewed by the US Food and Drug Administration to consider whether to grant an Emergency Use Authorization (EUA) to allow use of this vaccine.

In the studies of this vaccine, no one developed a severe allergic reaction, and side effects of the vaccine were similar to those of other vaccines, including fever experienced by 9% of volunteers. The vaccine did not appear to cause any excess serious complications.

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Article Information

Published Online: March 1, 2021. doi:10.1001/jama.2021.2927

Conflict of Interest Disclosures: Dr Creech reported receipt of personal fees from Altimmune, Horizon, Karius, Adaptive, Premier, and Astellas; receipt of grants from Merck, and serving as an investigator in the phase 3 clinical trials of the Moderna and Johnson & Johnson vaccines. No other disclosures were reported.

Source: Johnson & Johnson announces single-shot Janssen COVID-19 vaccine candidate met primary endpoints in interim analysis of its phase 3 ENSEMBLE trial. https://www.jnj.com/johnson-johnson-announces-single-shot-janssen-covid-19-vaccine-candidate-met-primary-endpoints-in-interim-analysis-of-its-phase-3-ensemble-trial

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    4 Comments for this article
    Vs mRNA
    Arthur Guerrero, MD |
    When Moderna and Pfeizer came out, the CDC FAQs spent quite a bit of time reassuring patients that mRNA does not enter the nucleus and therefore cannot interact with a person's DNA. It made sense. Can someone more educated in this area please explain how this cannot interact with a person's DNA? I know my patients are going to ask.
    The Johnson & Johnson Vaccine for COVID-19
    KS Lam |
    The effect of vaccine is measured by comparing the risk reduction in the two groups of participants (vaccinated and placebo groups) in randomized clinical trials. Relative risk reduction (RRR) or commonly known as vaccine efficacy is often used to express the magnitude of this effect which is derived simply by subtracting the relative risk from one. Alternatively, absolute risk reduction (ARR) is rarely used but is a much more meaningful measurement of risk. ARR is difference between the risks of disease in the two populations and defines the absolute magnitude of the risk.

    RRR is frequently reported in
    medical literature and news media. When vaccine effect expressed in relative terms, 95%, 94.6% and 66% VE were reported for Pfizer, Moderna and J& J vaccines respectively. In contrast, only Advisory Committee on Immunization Practices (ACIP) reported the ARR i.e 0.9%, 1.3% and 1.7% for Pfizer, Moderna and J& J vaccines respectively.

    In conclusion, when the magnitude effect was expressed in relative terms, much larger percentages result than when the publicly available clinical data was discussed in absolute terms. Thus, the presentation of RRR certainly created the perception bias of efficacy. Among the three vaccines, J&J vaccine has the highest ARR but lowest RRR.
    Re: Vs mRNA
    Brett Kistner, PharmD |
    Dr. Guerrero,

    Nucleo-cytoplasmic transport of mature mRNA (a highly conserved process essential for eukaryotic gene expression) is facilitated by/dependent on “transport complexes” that undergo disassociation following translocation, thereby preventing re-entry (1).


    1. Katahira J. Nuclear Export of Messenger RNA. Genes (Basel). 2015 Mar 31;6(2):163-84. doi: 10.3390/genes6020163. PMID: 25836925; PMCID: PMC4488659.
    Response to Dr. Guerrero
    Randy Morris, M.D. | University of Chicago
    I found a Medpage article (1) helpful; excerpts:

    "Adenoviruses -- even as they occur in nature -- just do not have the capacity to alter DNA. Unlike retroviruses such as HIV or lentiviruses, wild-type adenoviruses do not carry the enzymatic machinery necessary for integration into the host cell's DNA. That's exactly what makes them good vaccine platforms for infectious diseases, according to Coughlan.

    And, engineered adenoviruses used in vaccines have been further crippled by deleting chunks of their genome so that they cannot replicate, further increasing their safety.

    "The cell lines that are used for adenovirus vaccines are
    highly and well characterized cell lines. They are classified by the FDA as nonintegrating, meaning there has never been any evidence in humans and multiple animal models of vector-borne DNA integrating into a host," said Gregory Poland, MD, of the vaccine research group at the Mayo Clinic in Rochester, Minnesota."


    1. https://www.medpagetoday.com/special-reports/exclusives/91604