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Published on March 18, 2021

Johnson & Johnson COVID-19 Vaccine: 6 Facts You Should Know

Johnson & Johnson COVID-19 Vaccine: 6 Facts You Should Know

Notice: Following federal and state guidance, Cone Health plans to offer the Johnson & Johnson vaccine in weeks ahead at select locations. The CDC’s recommendation for vaccine providers to resume use of the Johnson & Johnson vaccine is available here. Get additional important information at

On Feb. 27, 2021, the FDA granted emergency use authorization for the Johnson & Johnson COVID-19 vaccine in the United States. There are now 3 vaccines available for groups eligible to get the shot: the Johnson & Johnson vaccine, the Pfizer vaccine and the Moderna vaccine. All three options are safe and effective methods of preventing COVID-19, but there are a few differences between them. Here are 6 key facts you should know about the Johnson & Johnson COVID-19 vaccine.

#1: The Johnson & Johnson vaccine is authorized and recommended for use.

U.S. health agencies have authorized and recommended this vaccine to prevent COVID-19 in those age 18 and older.

  • The FDA emergency use authorization is based on findings in clinical trials involving more than 44,000 people in 10 countries showing that the vaccine is highly effective and very safe.
  • The CDC recommended the J&J vaccine, which is just 1 dose, as a safe and effective means to prevent COVID-19.

#2: The Johnson & Johnson vaccine is highly effective.

The Johnson & Johnson vaccine is very effective in preventing severe disease and death associated with COVID-19. It has been tested in many countries, some of which had variant COVID-19 circulation.

  • 100% effective in preventing hospitalizations and death from COVID-19.
  • 85% effective in preventing severe COVID-19 that does not require hospitalization.
  • 72% effective in the US. The overall efficacy is 66% when including all countries.

Source: FDA Review of Efficacy and Safety of the Johnson & Johnson COVID-19 Vaccine, Feb. 26, 2021.

#3: The Johnson & Johnson vaccine is very safe.

This safety trials for this vaccine demonstrated mild side effects and no severe allergic reactions.

  • “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.”

Source: Journal of the American Medical Association Network, March 1, 2021

  • “Common side effects: Fatigue, fever headache, injection site pain, or myalgia (pain in a muscle or group of muscles), all of which generally resolve within a day or two. It has had noticeably milder side effects than the Pfizer and Moderna vaccines, according to the FDA report released in late February.”

Source: Yale Medicine, Feb. 27, 2021

#4: The Johnson & Johnson vaccine provides convenience.

The Johnson & Johnson vaccine requires only 1 shot, compared to two shots for the Pfizer and Moderna vaccines. While a one-dose shot may be more convenient, it’s important to remember that all available vaccines provide safe and effective protection against COVID-19. You can feel confident in taking the vaccine first available to you whether you are offered a one-dose or two-dose vaccine.

#5: The Johnson & Johnson vaccine does not contain the virus that causes COVID-19. Here’s how it works.

Scientists have used adenovirus, the shell of the virus, to carry the gene, or DNA, for the coronavirus spike protein into your cells so that antibodies can be produced. The adenovirus has been modified so that it can enter cells but cannot replicate to make you sick with a cold. The DNA quickly degrade in the human body and does not affect human chromosomes. When injected, the adenovirus causes production of the spike protein and immunity is created against COVID-19. The Johnson & Johnson vaccine cannot cause infection.

#6: The Johnson & Johnson vaccine can help us stop the spread of COVID-19 – but it’s still important to practice the 3 W’s.

The current 3 authorized vaccines are very effective against severe COVID-19. Similar to the flu shot, it is not 100% effective against all COVID-19, and you still might have mild disease. Since the majority of adults are not yet vaccinated, it is important to continue to adhere to the 3 W’s especially in the workplace, public and among those who are unvaccinated or at high risk for severe disease. Therefore, the best way to prevent COVID-19 remains wearing a mask, waiting 6 feet apart and washing hands often.

Want to learn more about the Pfizer and Moderna COVID-19 vaccines?

Cone Health Infectious Disease Medical Director Cynthia Snider, MD, MPH, answers 5 common questions about the mRNA-based COVID-19 vaccines from Pfizer and Moderna in this Q&A.

COVID-19 Vaccines at Cone Health

At Cone Health, we are fully committed to providing effective and safe vaccines to eliminate COVID-19 in our communities. Visit to find your vaccine group and sign up for our weekly email with information about COVID-19 vaccine appointment availability.

COVID-19 Vaccine Information

At Cone Health, we are fully committed to providing effective and safe vaccines in our communities. Click the button below to find your vaccine group and sign up for our weekly email with information about vaccine appointment availability.

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