What We Know So Far About The Johnson & Johnson Vaccine

by Elaine Roth
Andriy Onufriyenko/Getty

On February 27, 2021, less than two weeks shy of the one-year anniversary of the day the World Health Organization declared COVID-19 a pandemic, the FDA gave the green light to a third vaccine. A third light to lead us back to something closer to normal.

That third vaccine comes from Johnson & Johnson—it’s a single dose vaccine that has shown high efficacy in clinical trials. By all accounts, it could be a game-changer in the race to bring this pandemic to an end.

Scary Mommy spoke with Dr. Purvi Parikh, an immunologist with Allergy & Asthma Network who is also a principal investigator with the COVID vaccine trials to get a better understanding of the latest vaccine.

The Johnson & Johnson Vaccine Uses A Different Technology Than Pfizer and Moderna

Both Pfizer and Moderna are mRNA vaccines. According to Dr. Parikh, mRNA vaccines deliver a “recipe for the immune system to make spike protein.” The proteins made based on the mRNA instructions activate the immune system, and the immune system then makes antibodies and T-cells.

The Johnson & Johnson vaccine is an adenovirus vector vaccine. Rather than mRNA, it uses an inactivated (and harmless) common cold virus, which acts “like a vehicle to bring genetic material about COVID into the cells.” Once inside the cell, they use that material to make spike protein. In that way, it gets your immune system to activate.

The end point to all three vaccines is the same: to train your immune system to mount an immune response against COVID.

The Johnson & Johnson Vaccine Is A Single Dose Vaccine

Unlike Pfizer and Moderna which require two doses (three weeks and four weeks apart, respectively), the vaccine developed by Johnson and Johnson requires only a single dose. Most people will get the full protective effect of the vaccine two weeks after injection, though it can take up to four weeks. Dr. Parikh advises anyone who’s received the Johnson & Johnson vaccine to remain vigilant for four weeks post injection.

The Johnson & Johnson Vaccine Is 100% Effective At Preventing Death And Hospitalization

In clinical trials, Johnson & Johnson’s vaccine had an overall efficacy of 62%, according to Dr. Parikh. At first glance, compared to the mid ninety numbers coming from Pfizer and Moderna that might seem less than ideal. But that 62% on its own is only half a story.

The Johnson & Johnson vaccine has an 89% efficacy when it comes to preventing severe disease. More importantly, it is 100% effective at stopping death and hospitalization.

Even more promising is the efficacy of the Johnson & Johnson vaccine against the variants. Dr. Parikh observed that Johnson & Johnson studied their vaccine when the variants were more rampant than they were while Pfizer and Moderna were conducting their clinical trials. According to Dr. Parikh researchers found that the Johnson & Johnson “still protects against severe disease, death, and hospitalization,” even against the variants. Both Pfizer and Moderna are still investigating how their vaccines protect against variants and studying whether a booster shot will be necessary to combat variants.

There’s Evidence That The Johnson & Johnson Vaccine Stops Transmission

Potentially the most exciting news about the Johnson & Johnson vaccine is with respect to asymptomatic transmission. While Pfizer and Moderna are still studying whether their vaccines can stop asymptomatic transmission, Johnson & Johnson has found that its vaccine decreased asymptomatic transmission by 72%, according to Dr. Parikh.

When it comes to reaching herd immunity and protecting our most vulnerable from severe disease or death, that figure is crucial.

Side Effects Of The Johnson & Johnson Vaccine Are Comparable

When it comes to side effects, Johnson & Johnson’s vaccine is comparable “if not milder,” says Dr. Parikh. She noted that Moderna reported the most side effects and Pfizer was a close second. Johnson & Johnson seemingly has less than both, although Dr. Parikh emphasizes that all three have far less side effects than a vaccine like shingles.

Which all goes to say that the Johnson & Johnson is very safe. The only folks who should not take this vaccine are those who are allergic to any of the ingredients in the vaccine, specifically to the ingredient polysorbate-80. This is a common ingredient in other vaccines, including the flu and hepatitis vaccines, which means if you can get other vaccines, you are likely not allergic to this one, says Dr. Parikh.

To be safe, most healthcare providers will ask you to stay at least 15 minutes after injection, or 30 minutes if you’re prone to allergies, for observation. (This is true for Pfizer and Moderna, too.)

The Johnson & Johnson Should Be Available Soon

The key to ending this pandemic is to get as many people vaccinated as possible as quickly as possible. The Johnson & Johnson vaccine will go a long way to making that happen. Not only because it is a single dose shot, which measurably eases the logistical burden on healthcare providers, but also because it is more easily stored than other vaccines available.

Johnson & Johnson expects to deliver nearly four million doses of the vaccine this week and another 16 million by the end of the month. According to the New York Times, in a “historic” deal brokered by the White House and announced on March 2nd, Johnson & Johnson’s rival pharmaceutical company, Merck, will help manufacture the vaccine. “The move could substantially increase the supply of the new vaccine and ramp up the pace of vaccination just as worrisome new variants of the virus are taking hold in the United States,” the Times reports.

Dr. Parikh expects that the vaccine will be available very soon in doctor’s offices, megasites, and pharmacies everywhere.

Don’t Wait For One Shot Over Another

“You can’t compare Johnson & Johnson and the other two,” says Dr. Parikh who noted it was like comparing apples and oranges. “You have to look at the bottom line, which is they will save lives. Both will keep you out of hospital. ” She notes there’s no way to say that one is better than another until there’s a study where they are compared head to head within a similar population.

“Get whatever shot is available to you first,” advises Dr. Parikh. The Johnson & Johnson vaccine “will save your life; it will keep you out of the hospital.”

Three vaccines (with more on the way) within a year are a triumph of science, and a testament to what we can do when the best scientific minds in the world turn their attention to a problem. Three vaccines within a year a reason to hope that tomorrow will be a little brighter than today.

Information about COVID-19 is rapidly changing, and Scary Mommy is committed to providing the most recent data in our coverage. With news being updated so frequently, some of the information in this story may have changed after publication. For this reason, we are encouraging readers to use online resources from local public health departments, the Centers for Disease Control, and the World Health Organization to remain as informed as possible.