Information about the new Johnson & Johnson COVID-19 vaccine

The Johnson & Johnson/Janssen (J&J) COVID-19 vaccine has been approved and doses are now in South Carolina. I answer some commonly asked questions below.

How is the J&J COVID vaccine different from the Pfizer/Moderna vaccines?

  • The J&J vaccine puts DNA of the COVID spike-protein inside of another virus (called an adenovirus) and injects it into your body. Yes, you read that correctly! The good news is that while adenoviruses normally make us sick with common cold or flu-like symptoms, this specific adenovirus will not make you sick. The machinery that allows the adenovirus to reproduce in the body (and make you sick) has been removed. Once the adenovirus is taken up by a cell, it dumps the COVID spike protein DNA into your cell’s nucleus, where it is “read” and turned into…wait for it…mRNA of the COVID spike protein! You can kind of think of the J&J vaccine as a “parent” vaccine of the Pfizer/Moderna vaccines. There are a few more steps needed for the J&J vaccine to work, but the result is the same as the Pfizer/Moderna vaccines. If it is easier for you to understand this process in picture format, then this New York Times explanation is for you!
  • An interesting note: Do you remember hearing about Russia’s “Sputnik V” vaccine in late 2020? I remember being a little skeptical at the time. It turns out that the Sputnik vaccine uses the same adenovirus technology as J&J’s vaccine. However, unlike the US, Russia has been giving booster doses at 21 days which uses a different adenovirus strain. This is done in case a person was immune to the first adenovirus and their body destroyed it instead of allowing cells to take it up. We believe this possibility to be rare because we are using a rare adenovirus strain. One dose it is for the United States!
Rethink Healthcare 2021

The J&J vaccine is just one dose. Does it work?

  • Yes! This vaccine prevents 72% of moderate-severe COVID disease in the US, where moderate COVID illness is defined as a positive COVID test plus pneumonia-like symptoms OR 2 typical symptoms of COVID. It is 85% effective against severe COVID disease (ICU worthy illness). Yes, the 72-85% appears to be less effective than the Pfizer and Moderna vaccines, but the 72% effectiveness is only after 28 days. We believe our immunity continues to rise as time goes on. In the J&J vaccine trials, there were zero hospitalizations and deaths by day 49!

Does the J&J vaccine have as many side effects?

  • The J&J vaccine appears to have similar but lower rates of side effects as compared to the Pfizer/Moderna vaccines. Let me know how you do if you get this vaccine!

The Pfizer/Moderna vaccines are easy to update to cover new strains of the virus. Is the J&J vaccine as easy?

  • Yes, it would take a bit longer – a few weeks with J&J vs. a few days with Pfizer/Moderna. In general, we are trying to figure out if booster doses are needed to help protect us from COVID variants and what the best way to give these is.

You keep lumping the Pfizer and Moderna vaccines together. Is there really no difference between them?

  • Yes and no. They are very similar. I heard the difference between the vaccines described as Coca-Cola in a bottle vs. a can. However, you should not “mix” the two vaccines unless necessary. If you received a Moderna as your first vaccine, you should get Moderna as your second vaccine. There are no studies that look at the effect of “mixing” the two vaccines, so my recommendation is to avoid mixing them!

Which vaccine do you recommend I get?

  • I recommend you get whichever vaccine you have access to. Most people are not going to be able to choose which vaccine they are going to receive, because the demand is high and appointment slots are quickly being filled. It might take longer for your body to reach the highest level of protection after getting the J&J vaccine (up to 6 weeks or more). However, it takes 2 weeks after the 2nd Pfizer/Moderna vaccine to reach full protection, so that is also at 5-6 weeks after the first dose of the vaccine.

Want to learn more? Check out the Mayo Clinic’s website on COVID-19 vaccines The Johns Hopkins School of Public Health has a great Facebook site as well.

Have a good week! Feel free to contact me with any questions.
Melissa Boylan, MD, FAAFP
Family Physician and Owner of Noreta Family Medicine