How the Johnson & Johnson Covid-19 vaccine works and why it matters

Here’s what is known about how it works and how it will fit into the vaccine mix.

Johnson & Johnson’s Covid-19 single dose vaccine was shown to be 66% effective in preventing moderate and severe illnesses in a global Phase 3 trial, the company announced on Friday.

The vaccine is 85% effective overall in preventing hospitalization and death in all regions where it has been tested.

Its effectiveness against moderate and severe illnesses varied from country to country: 72% in the United States, 66% in Latin America and 57% in South Africa. This was measured from one month after the injection.

In South Africa, 95% of the cases in the trial were due to a variant known as B.1.351, which is known to be more contagious and carries mutations that can make the virus less susceptible to the immune antibody response – including vaccine-induced antibodies .

Even those who had moderate cases of Covid-19 in the study tended to develop a smoother course and less symptoms, said Dr. Mathai Mammen, Janssen’s global head of research and development.

From one month after the injection, all hospitalizations and deaths occurred in the placebo group.

How it works

The J&J vaccine is known as a non-replicating viral vector vaccine, using a common cold virus called adenovirus 26.

Scientists created this vaccine by taking a small amount of genetic material that encodes a piece of the new coronavirus and integrating it into a weakened version of adenovirus 26. J&J scientists have altered this adenovirus so that it can enter cells, but cannot replicate and train sick people.

AstraZeneca uses a similar platform, but its adenovirus comes from a chimpanzee.

The adenovirus carries the genetic material from the coronavirus to human cells, inducing them to make pieces of the coronavirus spike protein – the part it uses to bind cells. The immune system then reacts against these pieces of the coronavirus.

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“So, you are not being infected with the virus that can give Covid-19 when you receive this vaccine. It just has some of the harmless Covid virus proteins on its surface,” explained Dr. William Schaffner, an infectious disease specialist specialist in the Department of Health Policy at Vanderbilt University. “So, essentially, it’s a sheep disguised as a wolf, and when your immune system sees it, it responds to it and creates protection against it and, in the future, against the real virus that causes Covid-19.”

The technology used in the Covid-19 vaccine worked with Janssen’s Ebola vaccine.

How is it different from other Covid-19 vaccines?

Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia, said that the Moderna, Pfizer and J&J Covid-19 vaccines take a similar approach, but there is a small difference with the J&J approach.

“In the case of the Moderna and Pfizer vaccine, you’re just giving the gene in a lipid nanoparticle or a drop of fat,” said Offit. “In the case of J&J, you are giving the gene into a virus that cannot reproduce.”

The J&J vaccine is the only Covid-19 vaccine so far administered in a single dose. Moderna and Pfizer use two. Like Moderna, it can also be kept at normal refrigeration temperatures and does not need deep freezing like Pfizer.

How does a single dose affect the release?

A single dose would be much easier to administer and would mean that more people could be vaccinated, as none would need to be separated to give someone a second injection.

“This advantage increases in neon,” said Schaffner, who believes that adding a vaccine like this “would really speed up” vaccination efforts in the United States and around the world.

“If it is a single dose vaccine, then one billion doses of vaccine would translate into one billion vaccinated people,” said Dr. Dan Barouch of Harvard Medical School, who helped develop the Johnson & Johnson candidate vaccine in the Coronavirus Fact vs. podcast CNN Fiction.

The advantage of the cold chain

Johnson & Johnson's coronavirus vaccine generates immune response, few side effects, in the first tests

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The other advantage of & J is that it can be stored at normal refrigerator temperatures, unlike the Pfizer vaccine, which needs special freezers. The vaccine is stable for up to three months at 36 degrees F to 46 degrees F, the company said. This means that health facilities would not have to buy extra equipment to store the vaccine safely.

“If successful, these vaccines will be especially popular in the developing world because they would be easy to store and administer,” said Dr. Rafi Ahmed, director of the Vaccine Center at Emory University.

Vaccines would also be popular in rural communities in the United States and in regular doctor’s offices that may not have access or budget to purchase specialized equipment.

“In other words, we could get the vaccine to people,” said Schaffner, “instead of getting people to vaccines.”

What happens next?

The company will apply for what is known as emergency use authorization, or USA, from the FDA in early February.

The data will be closely examined by the FDA and consultants at the Centers for Disease Control and Prevention in the United States.

While the FDA analyzes the data, it schedules a public meeting of its Vaccine and Related Biological Products Advisory Committee. The committee is made up of independent scientists and public health experts who will discuss J&J data and make a recommendation to the agency.

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Once the order is submitted, “The FDA really analyzes data very carefully in each age group and each demographic group,” said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, during a call at Friday.

After the meeting, FDA team members consider the committee’s contribution along with the agency’s assessment of the company’s data and will make a decision on whether the vaccine should be authorized.

Shortly after a USA, the CDC’s Immunization Practices Advisory Committee, also known as ACIP, analyzes the data as well.

As soon as the CDC committee makes a recommendation and it is approved by the CDC director, the company plans to send vaccines immediately and can go to arms immediately.

How long does the authorization process take?

The process for the Johnson & Johnson vaccine should be almost the same as it was for the Moderna and Pfizer vaccines, according to Offit, who is a member of the FDA’s VRBPAC.

With the Pfizer vaccine, it took just over three weeks from the time the company sent its data to a USA. With the Moderna vaccine, it took just over two weeks.

If the vaccine is authorized for emergency use, “our plan is to have it delivered immediately after launch,” said Mammen.

How many doses are there?

The United States has ordered 100 million doses and the company makes them while testing the vaccine. Typically, companies hope to make the vaccine after it is approved, but that changed during the pandemic.

Johnson & Johnson says it can fulfill its 100 million dose commitment by June.

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