COVID-19 Resources

Nine Things to Know About the Johnson & Johnson Covid-19 Vaccine

Mar. 1, 2021

A third pharmaceutical company, Janssen Pharmaceutical Companies (a Johnson & Johnson company), was granted emergency use authorization on February 27, 2021 to distribute its COVID-19 vaccine.


This vaccine was tested in a randomized, double-blind, placebo-controlled clinical trial for people ages 18 and older. That means neither participants nor the researchers involved in the study knew who received a placebo (a saline shot) or the real vaccine. That allows them to collect, report and measure data without any biases.

The global study, which spanned three continents, included 43,783 participants.

Unlike the mRNA vaccines by makers Pfizer and Moderna, Johnson & Johnson’s version is the first adenovirus vaccine to receive emergency use approval from the U.S. Food and Drug Administration (FDA).

It’s also the first COVID-19 vaccine that requires just one dose.

With every new COVID-19 prevention approved for emergency use, questions arise about this new lifesaving vaccine.

Here’s what you need to know.

1. Johnson & Johnson’s vaccine is 85% effective in preventing severe disease and 100% effective in preventing hospitalization and death.

What’s most important about this vaccine, and about any vaccine, is its ability to prevent severe disease, hospitalization and death.

Studies in the United States showed the vaccine was 85% effective in preventing severe disease 28 days after receiving it.

Effectiveness in preventing severe disease continued to increase over time — no one in the study developed severe disease after Day 49 of being vaccinated. That means starting Day 50 after receiving the vaccine, not a single participant developed severe disease — and hasn’t since.

No study participants needed medical intervention (hospitalization/ICU admission, mechanical ventilation and extracorporeal membrane oxygenation, or ECMO [heart-lung bypass]) after Day 28 of vaccination.

It’s essential that we use all the tools in our toolbox to prevent further loss of life, as soon as we can.

“We cannot wait for enough vaccine supply from Pfizer and Moderna to protect our community,” said Carl J. Fichtenbaum, MD, professor in the Division of Infectious Diseases in the Department of Internal Medicine at the University of Cincinnati College of Medicine and a UC Health physician.

“It will take a multi-pronged approach to end this pandemic, especially as variant strains continue to emerge,” he said. “A vaccine that is very effective in preventing severe disease will save countless lives, decrease the number of people needing to be in the hospital and bring us back to normal, faster.”

There’s no doubt that the Johnson & Johnson vaccine will lessen the toll of this pandemic on human life and suffering.

2. Johnson & Johnson’s vaccine is 72% effective in preventing COVID-19 infection in the U.S.

Clinical trials in the U.S. showed this vaccine is 72% effective in preventing COVID-19 infection 28 days after receiving it.

The trial in the U.S. was part of a global study, which also tested the effectiveness of the vaccine in Latin America and South Africa.

Johnson & Johnson announced its vaccine is 66% effective globally, based on results from all three trials.

Latin America’s study showed 66% effectiveness, while South Africa’s was 57% — both likely lower because of the presence of variant strains in those countries (though still provide significant protection). The variant strains was a hurdle neither Moderna nor Pfizer had to overcome in clinical trials that demonstrated their higher efficacy rates.

Seventy-two percent is relatively high for overall vaccine effectiveness. Compare that to the annual influenza shot, which ranges from 50–60% effectiveness in any given year.

The vaccine was shown to be less effective in people with comorbidities (health conditions), with 53.4% efficacy in participants ages 18–59 and 33.2% efficacy in participants ages 60 and over.

“The differences in efficacy rates among vaccines from Johnson & Johnson, Pfizer and Moderna is astronomically less important than getting as many people vaccinated as quickly as possible with any of the three approved vaccines,” said Dustin J. Calhoun, MD, associate professor in the Department of Emergency Medicine at the UC College of Medicine and medical director of Emergency Management at UC Health.

“Vaccinating more people faster is critical to reaching herd immunity and preventing the emergency of progressively more concerning variants with significant potential to greatly degrade the efficacy of all current vaccines,” he added.

3. The Johnson & Johnson vaccine only requires one dose.

Unlike vaccines from Pfizer and Moderna, the version from Johnson & Johnson is administered in just one dose.

A vaccine that only requires one dose will remove significant logistical and social barriers to ensuring Americans have access.

“Since December, UC Health has worked hard to ensure our vaccination centers offer an easy, seamless experience — and that includes scheduling and access for the second dose,” Dr. Calhoun said.

“But, we know economic and social barriers, such as transportation, make it difficult for some to return for a second dose,” he continued. “A one-dose vaccine will help protect our most vulnerable populations and ultimately help our community and country reach herd immunity.”

Researchers are currently investigating the effectiveness of the vaccine if it’s given in two doses.

4. It’s the first viral vector vaccine approved for use in the U.S.

Similar to the mRNA vaccine technology, scientists have been studying viral vectors for decades.

Since the 1970s, researchers around the globe have published hundreds of studies about viral vector vaccines.

Recently, they have been tested in human trials for viruses like HIV, Zika and respiratory syncytial virus (RSV). In West Africa and the Democratic Republic of Congo, two viral vector vaccines have been used to fight Ebola outbreaks.

Some of these vaccines were produced by platforms from Janssen Pharmaceutical Companies.

So, what is a viral vector vaccine?

A “vector” refers to a vehicle used to get immunity-stimulating material into the body.

In this case, the vector for the vaccine is a weakened strain of human adenovirus 26, a version of the common cold. You cannot get adenovirus from this strain, as it has been engineered so that it doesn’t reproduce.

Scientists insert genetic instructions for the spike protein found on the surface of the coronavirus into the weakened adenovirus.

The adenovirus acts like a Trojan horse for the genetic material, entering the cell without raising suspicion.

The genetic material for the spike protein, however, is copied into mRNA.

From here, the vaccine works much like mRNA vaccines. The cell reads the mRNA (a set of genetic instructions) and begins making spike proteins.

The immune system recognizes the spike proteins as a foreign invader and creates antibodies to fight off the intruder. Because it’s only one part of the coronavirus (like the tire of a car, and not the whole car itself), it can’t cause COVID-19.

These antibodies remember the shape of this particular spike protein, so if the real coronavirus ever enters your body, it has the defenses already in place to fight it off.

5. Release of the Johnson & Johnson vaccine could double the number of total vaccines available in the U.S.

In Ohio, as of the end of February, about 200,000 vaccines are distributed across the state every week.

According to Dr. Fichtenbaum, in order to vaccinate all Ohioans by the fall, we’ll need that weekly number to increase to about 500,000.

Once distribution of Johnson & Johnson vaccines begins, experts expect Ohio will receive significantly more doses per week (though an exact number is not known).

This milestone will allow more people to be vaccinated across the country sooner.

6. It doesn’t require ultra-cold storage.

Another characteristic of this vaccine that will help broaden access to more individuals is its storage requirements.

The Johnson & Johnson vaccine will remain stable in refrigerators set at 36°F–46°F for three months, and freezers at -4°F for two years. It can be shipped using the same cold chain technologies used for other medications.

The Pfizer vaccine was originally approved to be stored between -112ºF and ‑76ºF, and the Moderna vaccine between -13° and 5°F. These storage requirements lead to more expensive and complex processes than will be needed for the Johnson & Johnson vaccine. Only organizations with very expensive ultra-cold storage equipment have been able to store these vaccines.

“Smaller healthcare systems and organizations that don’t have ultra-cold storage will be able to store the Johnson & Johnson vaccine, which means getting more shots into more arms — especially to those who live or work in more remote locations,” Dr. Calhoun said.

7. Studies show it’s very safe for those across races, ages and people with various health conditions.

An independent group of experts from the Data and Safety Monitoring Board found that there were no significant safety concerns associated with this vaccine.

There were no cases of anaphylaxis (severe allergic reaction) reported in the studies. In fact, there were more serious adverse events reported by study participants who received the placebo than by people who received the vaccine — which suggests these events were coincidence and not directly caused by the vaccine itself.

This safety information applies to participants from diverse backgrounds, races and ages.

Of the 43,783 participants, 45% were female and 55% were male. In the U.S., 35% of participants were non-white and/or Latino:

  • White/Caucasian: 74%
  • Hispanic and/or Latino: 15%
  • Black/African American: 13%
  • Asian: 6%
  • Native American: 1%

Across all three continents in the study, 59% of participants were White/Caucasian, 45% were Hispanic and/or Latino, 19% were Black/African American, 9% were Native American and 3% were Asian.

Forty-one percent of participants had health conditions that increase their risks for severe COVID-19:

  • Obesity: 28.5%
  • Hypertension (high blood pressure): 10.3%
  • Type 2 diabetes: 7.3%
  • HIV: 2.8%

8. The Johnson & Johnson vaccine will help us get to herd immunity faster.

Herd immunity occurs when enough people become immune to a disease to make its spread unlikely. As a result, the entire community is protected, even those who are not themselves immune. 

Herd immunity can occur through vaccination. It can also occur through natural infection, but many people will suffer and die while we wait for herd immunity from natural infection. Vaccination does not result in loss of human life, which is why it is the better way to achieve herd immunity.

We need at least 70% of the country to be immune in order to achieve sufficient herd immunity, though some experts believe we need as high as 85%. The real number is not known.

But what we do know is that all vaccines available to us will help get us there.

Ending this pandemic will mean that we must do our part, for the betterment our ourselves, our friends and our neighbors.

9. You may not get to choose the manufacturer of your COVID-19, but you should still opt to get any COVID-19 vaccine that you’re offered.

Availability of vaccines at health systems, pharmacies and health departments depend on many factors — the speed at which manufacturers can produce them, how states allocate them and more.

To date, those who have received the vaccine haven’t been able to choose between Moderna and Pfizer.

Many health systems only have enough supply to administer vaccines from one manufacturer at a time.

So, when you pull up to your appointment, there likely won’t be more than one kind of vaccine on hand for you to choose from. Receiving any vaccine available in the U.S. as soon as possible is much better than the risks caused by delaying that vaccination.

Dr. Fichtenbaum said it’s important not to get too caught up in the numbers.

All vaccines are tested in different environments. It’s possible that if the Pfizer or Moderna vaccines were tested more recently, now that COVID-19 variants are spreading in the U.S., the results might be different.

How well a vaccine works is often much more complex than a single number. Plus, the Johnson & Johnson vaccine is shown to be most effective against the most severe forms of COVID-19.

“We will all be better protected if we can vaccinate more people,” Dr. Fichtenbaum said.

On April 13, 2021, the FDA and CDC announced a temporary pause in the distribution of this vaccine. Click here to learn more.