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How Is The Johnson & Johnson COVID-19 Vaccine Different From Pfizer's And Moderna's?

Health workers administer coronavirus vaccine shots at a drive-thru mass vaccine clinic at the Circuit of the Americas on Feb. 27.
Julia Reihs
Health workers administer coronavirus vaccine shots at a drive-thru mass vaccine clinic at the Circuit of the Americas on Feb. 27.

Vaccine providers in Central Texas are getting their first shipments of the Johnson & Johnson COVID-19 vaccine this week. It’s the third one to get approval in the U.S. — and it works a little differently than the Moderna and Pfizer vaccines.

One of the benefits of the Johnson & Johnson vaccine is the fact that it only requires one dose, says Dr. Manish Naik, the chief medical information officer at Austin Regional Clinic. The clinic was allocated several hundred doses of the vaccines this week.

“One of the complexities of the vaccine rollout for COVID-19 vaccination has been the process of getting a patient scheduled for that second dose and then making sure they get that second dose, because they're really not fully vaccinated until they've received both doses,” Naik said. “So, the Johnson & Johnson vaccine makes that a lot easier because it's a single-dose vaccine.”

It’s also easier to store. The vaccine can be stored at normal refrigeration temperatures for several months unlike the others, which don’t last nearly as long at those temperatures.

“You can use it as you go and you don't have those same restrictions,” Naik said. “So for a rural community, they wouldn't need any special equipment, and there's less of that worry of ‘you've taken this out of the freezer and now you have only X number of days, so you have to use it.’”

All three of the vaccines cause cells in the body to produce a harmless part of the coronavirus called the spike protein. Our immune system recognizes the protein doesn’t belong, triggering the body to fight off what it thinks is an infection. Through this process, we build up immunity to COVID-19 — our bodies learn how to protect us against future coronavirus infections.

The Pfizer and Moderna vaccines use strands of genetic material known as messenger RNA, which instructs cells in the body to create the spike protein. The Johnson & Johnson vaccine, on the other hand, is a viral vector vaccine. It uses a common cold virus — one that’s been altered so it can’t get you sick — to deliver the instructions to cells for making the spike protein.

“So, although the vaccines have a different way of delivering the message to the body to produce spike protein, the net effect is the same,” Naik said. “The body produces spike protein and that results in an immune response, which creates the immunity against the virus.”

Some people might think certain vaccines are better than others because of the efficacy rates currently available from their clinical trials. The Johnson & Johnson vaccine was found to be 66% effective at preventing laboratory-confirmed COVID-19 illness worldwide (72% in the U.S.). Moderna’s and Pfizer’s were about 95% effective at this after the second dose.

But Naik says the trials aren’t really comparable, since they were done at different times and in different areas. The Johnson & Johnson vaccine, for example, was done at a time when more variants were around.

“It was also done in countries like Brazil and South Africa, where we are aware that there are variants there that may be less responsive to some of these vaccines, at least in terms of preventing milder infections,” Naik said. “So, when you compare the efficacy data of Johnson & Johnson versus Pfizer and Moderna, you’re not really comparing apples to apples.”

The more important metric to pay attention to, experts say, is the vaccines’ abilities to prevent severe disease. The trial found the Johnson & Johnson vaccine was 85% effective in preventing severe or critical COVID-19 illness. No deaths related to COVID were reported among people in the study who got the vaccine.

Health officials, including Naik, have been advising people to take the first vaccine they’re offered and not hold out for one they think is better than the other.

Jaquelin Dudley, associate director of the LaMontagne Center for Infectious Disease at UT Austin, agrees. She said as time goes on, more data will become available — as well as more vaccines.

“We may be getting a coronavirus shot every fall,” Dudley said. “And so just because you can’t have the best looking shoes on the rack doesn’t mean you shouldn’t buy any shoes. And we don’t really know what the best looking shoes are.”

The best way to protect yourself, your loved ones and the community, she said, is to take the first vaccine you can.

Some make the case that the difference between the vaccines matters. "It’s certainly true that all three of the FDA-authorized vaccines are very good—amazing, even—at protecting people’s health," health consumer advocate Hilda Bastian writes in The Atlantic. "As for the claim that the vaccines have proved perfectly and equally effective at preventing hospitalization and death? It’s just not right."

The Johnson & Johnson vaccine is recommended for people 18 and older.

Like with the Pfizer and Moderna vaccines, the Centers for Disease Control and Prevention says some side effects, such as muscle pain, chills and fever, can occur a day or two after getting the Johnson & Johnson vaccine but should go away within a few days.

There is some data that shows side effects may be less prevalent with the Johnson & Johnson vaccine, possibly because it only requires one shot. Naik said he thinks it’s too early to tell, though, if Johnson & Johnson will have fewer side effects than the others.

“Some of the side effects, even with Pfizer and Moderna, really became more evident once more people got the vaccine,” he said. “Once we had millions of people that had gotten the vaccine, we had a much better indication.”

Getting the Johnson & Johnson shot doesn’t immediately protect you from COVID-19. It takes a few weeks for your body to build up immunity. Clinical trials showed people had the most protection two weeks after getting the shot, according to the CDC.

People are still being advised to wear masks and social distance in public even after they’re fully vaccinated. That’s because it’s not yet known whether the vaccine prevents people from spreading the disease, even if it does help prevent them from getting sick themselves.

“That's still an open question, even though I think based on other viruses, it's very likely that once your immune system has been able to control that virus infection so that you're not getting a disease, you're not as likely to transmit it,” Dudley said. “But since we still don't know and there's new variants out there ... it's just a precaution so we don't have another wave of the disease.”

The CDC issued new guidance earlier this week for what vaccinated people can do, like gather indoors with other fully vaccinated people without masks or social distancing measures.

Got a tip? Email Marisa Charpentier at mcharpentier@kut.org. Follow her on Twitter @marisacharp.

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Marisa Charpentier