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What to Know About the Johnson & Johnson COVID Vaccine

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Key Takeaways

  • Johnson & Johnson has begun shipping doses of its newly authorized vaccine across the United States.
  • The vaccine is formulated differently than the Pfizer and Moderna vaccines, and it requires only one dose.
  • This is the third COVID-19 vaccine in circulation in the U.S.

Another vaccine joined the fight against the COVID-19 pandemic, bringing further hope to American families that a return to normalcy may be on the horizon.

Corporate powerhouse Johnson & Johnson has come forward with its own version of a COVID-19 vaccination, Ad26.COV2.S, which is from the company’s pharmaceutical arm Janssen. The U.S. Food and Drug Administration (FDA) granted Emergency Use Authorization, or EUA, to the vaccine for people 18 and older on February 27, 2021.

Having a third vaccine in circulation should help get more shots in arms over the next several months, and it could help alleviate supply issues for Pfizer and Moderna vaccines. Read on to learn more about what your family should know about the J&J vaccine.

How Does the J&J Vaccine Differ From Pfizer and Moderna?


The Johnson & Johnson vaccine was designed to be slightly different from the existing vaccines made by Pfizer and Moderna. First and most importantly for the general public, it’s currently intended to be a single-dose vaccine, instead of being delivered as a series of two vaccinations.

That’s not the only difference, however. The Johnson & Johnson shot is an adenovirus-vectored vaccine rather than an mRNA vaccine. That’s science-speak for a vaccine that uses a common cold virus (commonly called an adenovirus) to hitchhike the coronavirus genes to produce those same viral proteins, explains Dr. Nitin Desai, MD, CEO, and chief medical officer of COVID PreCheck.

As a result, the J&J vaccine does have a slightly lower rate of effectiveness than its counterparts. Both the Moderna and the Pfizer vaccine boast effectiveness rates in the mid-90% range. Meanwhile, global data suggests that J&J's vaccine is 85% effective at preventing moderate to severe COVID symptoms, 28 days after receiving the shot.

This is due largely to the fact that the vaccine doesn’t contain messenger RNA like Pfizer and Moderna shots do, and in part because it’s a one-dose vaccine. It's worth noting, though, that trials showed Johnson & Johnson's vaccine offering complete protection against hospitalization and death from COVID after 28 days. This is ultimately the most important thing as we strive toward herd immunity.

Either way, it’s a suitable solution to the short supply of COVID-19 vaccines that currently exists, and it can likely give more Americans protection from the virus in short order, says Desai. What’s more, the vaccine doesn’t require freezing due to its lack of mRNA, and it can therefore be distributed more quickly and effectively than Moderna and Pfizer shots.

Is the Johnson & Johnson Vaccine Safe? 

Yes. According to Desai, “The Johnson & Johnson vaccine has an acceptable safety profile and could be an alternative for some with a history of allergies to other vaccines or their ingredients.”

That’s great news for people who might be naturally wary of vaccines and thus struggling with the decision to get this important shot. “In clinical trials, there have been fewer severe side effects from the Johnson & Johnson vaccine, including reactions like anaphylaxis,” Desai says.

Should You Get the J&J Vaccine If You're Pregnant?

There are still some unknowns regarding the use of COVID vaccines among pregnant individuals, says Desai. “J&J vaccine safety in pregnant women has not been tested, and safety data are not yet available.”

Despite this, in studies conducted to date, there is no evidence that there is a detrimental effect of the COVID vaccine on pregnancy, says Dr. Barry Witt, a board-certified reproductive endocrinologist and medical director for WINFertility.

“One concern that has been raised is that the coronavirus’s spike protein shares small stretches of the same genetic code as placental protein, and that this could result in an immune reaction against the placenta,” Witt says. “However, these proteins are otherwise completely different in structure and the vaccine does not induce an immune reaction against the placental protein, so this should not be a concern.”

Importantly, neither the American College of Obstetricians and Gynecologists (ACOG) nor the American Society for Reproductive Medicine (ASRM) recommend withholding any COVID vaccine from pregnant or lactating women, assuming they otherwise meet the criteria for obtaining the vaccine (over age 16 for Pfizer and over age 18 for Moderna and Johnson & Johnson).

It’s also important to remember that a COVID infection can potentially be more dangerous and/or severe for pregnant women, so this should be weighed into the decision to receive a vaccine or not.

When Can I Get the J&J Vaccine? 

Johnson & Johnson expects to deliver enough doses to vaccinate more than 20 million people in the U.S. by the end of March and to deliver 100 million doses of the vaccine across the U.S. during the first half of 2021.

Recommendations for who should receive the vaccine first will be based on the CDC's Advisory Committee on Immunization Practices (ACIP) from the National Academies of Science, Engineering, and Medicine.

What About My Kids?

As with the Pfizer and Moderna vaccines, children were not a part of initial Johnson & Johnson clinical trials, and they will not be eligible to receive the vaccine until it is shown to be effective—and safe—for kids. That makes it all the more important for adults to sign up to be vaccinated as soon as they are eligible.

Johnson & Johnson does plan to test the vaccine on children older than 12 and younger than 18, as well as on infants, pregnant women, and people who are immunocompromised, but specifics have not yet been released.

Fortunately, evidence continues to show that kids are more likely to experience less severe COVID symptoms in the event that they do become infected.

What This Means For You

If you're eligible, you could be one of millions of Americans receiving the single-shot Johnson & Johnson vaccine. With a third vaccine option now available, we are a step closer to closing the curtain on the coronavirus pandemic. 

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Article Sources
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  1. U.S. Food & drug Administration. Janssen COVID-19 Vaccine EUA Fact Sheet for Healthcare Providers. Published February 27, 2021.

  2. U.S. Food & Drug Administration. Janssen COVID-19 vaccine frequently asked questions. Updated February 27, 2021.

  3.  Johnson & Johnson. Johnson & Johnson COVID-19 vaccine. Authorized by U.S. FDA for emergency use - first single-shot vaccine in fight against global pandemic. Published February 27, 2021.

  4. The American College of Obstetricians and Gynecologists. Vaccinating Pregnant and Lactating Patients Against Covid-19. Updated March 4, 2021.

  5. American Society for Reproductive Medicine. American Society for Reproductive Medicine (ASRM) Patient Management and Clinical Recommendations During the Coronavirus (COVID-19) Pandemic. Updated February 22, 2021.

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  7. Dooling K, Marin M, Wallace M, et al. The Advisory Committee on Immunization Practices’ updated interim recommendation for allocation of COVID-19 vaccine — United States, December 2020MMWR Morb Mortal Wkly Rep. 2021;69:1657-1660. doi:10.15585/mmwr.mm695152e2