An Overview of the Johnson & Johnson COVID-19 Vaccine

On February 27, Johnson & Johnson's vaccine against the coronavirus disease 2019 (COVID-19) became the third COVID-19 vaccine to receive emergency use authorization (EUA) from the U.S. Food and Drug Administration (FDA).

The company worked with its pharmaceutical arm Janssen to develop the vaccine under the project names Ensemble and Ensemble 2. The company enrolled participants for its late-stage in September, and tested its vaccine with two different doses.

After a single dose was found to be effective in clinical trials, Johnson & Johnson applied for the EUA for the single dose. Now the first COVID-19 vaccine to be given in one dose in the U.S., it's authorized for adults ages 18 and older.

J&J covid

Images By Tang Ming Tung / Getty Images

How It Works

Johnson & Johnson's vaccine is a single-dose adenovirus-based vaccine. It is a viral vector vaccine that uses a weakened live pathogen (adenovirus) as the delivery method (vector) for transporting a recombinant vaccine for COVID-19.

Recombinant vaccines use a small piece of genetic material from the virus to trigger an immune response. This genetic material for COVID-19 does not replicate in the body. A specific piece of the virus can be targeted, and recombinant vaccines are common and generally safe to use in a large population of people—even those with chronic health problems or who are immunocompromised.

There can be some drawbacks to recombinant vaccines. One example is that booster shots may be required over time. Examples of recombinant vaccines are pneumococcal vaccines and vaccines for meningococcal disease.

The science behind recombinant adenoviral vector vaccines has been around for a long time, but the only commercially available adenovirus-based vaccine is a rabies vaccine for animals. Adenovirus-based vaccines may also pose some problems in that the adenovirus is so common that the vaccine may not be as effective once booster doses are given, or that some people may already have immunity to the virus used in the vaccine.

How Effective Is It?

Johnson & Johnson announced that its single-dose vaccine was 66% percent effective at preventing moderate to severe disease from COVID-19 and 85% effective at preventing severe disease. This effectiveness in the Phase 3 trial was reached 28 days after vaccination.

The trial had a temporary delay in October when it paused for an unexplained illness, although no specific details were provided about what happened due to patient privacy. Regulators determined that the event was not related to the vaccine and the trial was safe to resume.

The efficacy against moderate to severe COVID-19 infection varied by region in the trial. It was 72% in the United States, 66% in Latin America, and 57% in South Africa.

The vaccine was also found to be fully protective against hospitalization and death and the protection against severe disease included multiple variants of COVID-19, including the B.1.351 variant found in South Africa.

When Will It Be Available? 

The Johnson & Johnson vaccine was granted emergency use authorization from the FDA for its single-dose vaccine, and distribution is underway.

Johnson & Johnson has a contract with the U.S. government for 100 million doses (the equivalent of $10 per dose) and the option to purchase an additional 200 million doses.

The U.S. government announced a partnership with Merck to help accelerate the production of the Johnson & Johnson vaccine. Merck will receive up to $268.8 million from the Biomedical Advanced Research and Development Authority (BARDA) to adapt and make available its manufacturing facilities for producing the Johnson & Johnson COVID-19 vaccine.

The Centers for Disease Control and Prevention (CDC) is leading vaccination efforts, and all orders of COVID-19 vaccines, regardless of the manufacturer, will go through the agency. CDC is overseeing the distribution of vaccines, too.

CDC’s Advisory Committee on Immunization Practices (ACIP) has made recommendations on how to prioritize vaccine supplies, but it can vary by state during distribution. Healthcare workers and people living in long-term care facilities are the first to receive the vaccines, and additional priority groups include essential workers, people ages 65 and older, and people with high-risk medical conditions.

According to the CDC, there are more than 18 million healthcare workers in the United States and about 1.3 million Americans living in long-term care facilities.

The CDC estimated that it will take several months before the supply of vaccines catches up to the demand. Guidance on who will receive the vaccine and when will be updated as supplies become available.

The United States alone has a population of about 330 million. President Biden announced on March 2 that there could be enough COVID-19 vaccine doses available for all U.S. adults by the end of May.

Although little information is available on the specifics of when everyone will receive the vaccine and where they can get it, state and local health departments will be coordinating efforts to distribute doses of the vaccines as they become available. The vaccine should be available both in physician offices and retail locations like pharmacies that administer other vaccines.

How Much Will a COVID-19 Vaccine Cost?

Once the vaccine is available, any doses purchased by the U.S. government will be free to its citizens. While the vaccine itself is free, the facility or agency that offers the vaccine may charge a fee for administration. Public health programs and insurance plans will reimburse patients for any costs associated with COVID-19 vaccination, and no one can be denied a vaccine if they are unable to pay a vaccine administration fee.​

Who Can Get the Johnson & Johnson Vaccine?

Early vaccine efforts for most COVID-19 vaccine candidates are focusing on adult populations, with vaccine options for children and teens expected later in 2021.

The Johnson & Johnson vaccine is no exception. The vaccine is authorized in adults ages 18 and older, and its Phase 3 trials were conducted in adults aged 18 and up with significant representation of individuals over age 60.

Side Effects and Adverse Events

In every clinical trial, participants are asked to record any reactions they have after receiving a medication or vaccine. Adverse reactions are considered to be medication reactions directly caused by a vaccine, whereas a side effect is a physical reaction to a medication.

Initial safety information released for the vaccine shows that the most common reactions after the vaccine was administered included:

  • Injection site pain, redness, or swelling
  • Fatigue
  • Headache
  • Muscle aches
  • Nausea
  • Fever

People who are immunocompromised, including those receiving immunosuppressant therapies, may have a diminished immune response to the vaccine, according to the FDA.

Funding and Development

Johnson & Johnson co-funded the development of the vaccine as part of Operation Warp Speed, a public-private partnership initiated by the U.S. government to facilitate and accelerate the development of a COVID-19 vaccine, manufacturing, and distribution of COVID-19 vaccines, with funding from the Biomedical Advanced Research and Development Authority (BARDA)—a U.S. government program aimed at furthering the manufacture and distribution of vaccines to fight COVID-19. Johnson & Johnson said $1 billion has been invested in the vaccine project by both the company and BARDA.

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  8. Merck. Merck to help produce Johnson & Johnson's COVID-19 vaccine; BARDA to provide Merck with funding to expand Merck's manufacturing capacity for COVID-19 vaccines and medicines. Updated March 2, 2021.

  9. Centers for Disease Control and Prevention. Evidence table for COVID-19 vaccines allocation in Phases 1b and 1c of the vaccination program. Updated December 22, 2020.

  10. Centers for Disease Control and Prevention. Healthcare workers. Updated January 13, 2017.

  11. Centers for Disease Control and Prevention. Nursing home care. Updated May 20, 2020.

  12. Centers for Disease Control and Prevention. Frequently asked questions about COVID-19 vaccination. Updated February 25, 2021.

  13. Food & Drug Administration. Janssen COVID-19 vaccine EUA fact sheet for recipients and caregivers. Updated February 27, 2021.

  14. Food & Drug Administration. Janssen COVID-19 EUA fact sheet for healthcare providers. Updated February 27, 2021.

  15. Johnson & Johnson. Vaccine candidate for COVID-19; landmark new partnership with U.S. Department of Health & Human Services; and commitment to supply one billion vaccines worldwide for emergency pandemic use. Updated March 30, 2020.

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