Q&A: Johnson & Johnson’s vaccine is coming to San Diego. Here’s what you need to know about it

Vials of Johnson & Johnson's  COVID-19 vaccine.
The FDA said Johnson & Johnson’s one-shot vaccine offers strong protection against what matters most: serious illness, hospitalizations and death.

(The Associated Press)

Dr. Mark Sawyer of Rady Children’s Hospital recommended that the FDA authorize Johnson & Johnson’s vaccine


A third COVID-19 vaccine is coming to town — this time from American pharma giant Johnson & Johnson.

On Sunday, the Centers for Disease Control and Prevention endorsed the vaccine’s use among those 18 and up. The move came a day after the Food and Drug Administration authorized the vaccine, heeding the recommendation of an independent panel of doctors and researchers.

Infectious disease expert Dr. Mark Sawyer of Rady Children’s Hospital served on that panel. We reached out to him to understand how this vaccine works and how it compares to the Moderna and Pfizer vaccines.

Sawyer sat on the FDA advisory panels for those vaccines, too, and is one of 11 experts tapped by California Gov. Gavin Newsom to review the safety and effectiveness of authorized coronavirus vaccines. In the past, he has served on a committee that helps the Centers for Disease Control and Prevention issue national vaccination recommendations.

This conversation has been edited for length and clarity.

Q. Is this a vaccine you’d be comfortable with a family member getting?

A. Absolutely. I would be comfortable getting it personally or having one of my family members get it. It’s very effective, particularly at preventing serious disease — the kind of disease that puts you in a hospital or in an intensive care unit. It’s also the first vaccine for which we have data right out of the chute about how it’s working against some of these variant strains that have started to circulate in the world.

Q. The Pfizer and Moderna vaccines use messenger RNA to teach the immune system to target the surface of the coronavirus. How does Johnson & Johnson’s vaccine work?

A. It’s very similar in that this vaccine encodes the same surface protein that the messenger RNA vaccines encode, and so the end result to your immune system is the same — it’s reacting to the surface protein on SARS-CoV-2. The difference is that this vaccine is carried into cells by a virus that has been inactivated so that it cannot cause any illness, but it still delivers the DNA into the cells so that they make the SARS-CoV-2 surface protein. One of the Ebola vaccines that’s being used in Africa is made the same way.

Q. How safe and effective is this vaccine?

A. It looks similar to the Moderna and Pfizer vaccines in that it causes sore arms and some achiness and fevers. My overall sense is that the side effects may be a little less than what we saw with the messenger RNA vaccines. But the good news is, whenever your body reacts that way, it’s an indication that the immune response is working.

And when you talk about efficacy, it all depends on what you’re trying to prevent. What we know about the Johnson & Johnson vaccine so far is that it looks like it’s about 65 percent effective against preventing all disease, but 85 percent effective at preventing severe disease.

Comparing COVID-19 vaccines available in the US

Q. Can you put those numbers in context? Moderna and Pfizer reported that their vaccines are about 95 percent effective in preventing disease. Is this vaccine less effective?

A. Just to remind everybody, the threshold the FDA set before we started all this COVID vaccine development was 50 percent effectiveness. So we’re above that by a significant amount. This is a more effective vaccine than standard influenza vaccines are every year.

People also need to keep in mind that it was studied later than the messenger RNA vaccines. So it was studied in an environment in the world where there were more variant strains. It’s really not appropriate to directly compare the results from studies that were done much earlier.

This may turn out in the long run to be a better COVID-19 vaccine, depending on what we learn about how these vaccines work against the various strains. One of the places the Johnson & Johnson trial was done was in Brazil, where they have already a significant amount of circulating resistant virus, and South Africa.

Q. This will be the first one-shot coronavirus vaccine to be used in the U.S., and it doesn’t need to be stored in a freezer. How important are those features?

A. There are a lot of advantages to a single dose. If we have the same amount of vaccine, obviously we could immunize twice as many people in the same period of time. That’s going to let people go back to school, go back to work, get out into the community more, it just makes logistics so much easier. We don’t have to keep track of which vaccine you got so that your second dose is given with the same one. You don’t have to live through any side effects twice. It’s pretty huge.

Also, it’s not easy to keep something frozen as you transport it around the community and ship it across the country and all of the things that have to happen to deliver a vaccine to everybody who needs it — particularly in more remote, rural areas. The Johnson & Johnson vaccine is more durable, so its effectiveness is going to hold up even through less-than-ideal shipping and storage conditions. That’s going to make a big impact on outcomes of the pandemic, because some of those same communities have increased risk of disease.

Q. What would you say to people who’d prefer to pass on the Johnson & Johnson vaccine for a chance to get the Moderna or Pfizer shot?

A. They’re basically rolling the dice, hoping they’re not going to get exposed to COVID while sitting around waiting to get a different vaccine. And if they guessed wrong and end up sick, you made the wrong decision.

Also, the more people we get immunized, the faster the pandemic gets under control and the less variant strains circulate. And we’ll develop the herd immunity we’re all striving for, which is when enough of the population is protected that even people who aren’t vaccinated indirectly get protected because the virus goes away in our community. We need to get a handle on this pandemic now if we want to get back to life as normal.

Graphic explaining herd immunity.