Johnson & Johnson Prepares For COVID-19 Vaccine Human Trials

Clinical trials are well underway for three COVID-19 vaccine candidates being funded by the United States. Moderna and AstraZeneca have begun human trials, and Johnson & Johnson plans to do so by the end of July.

Even with over $2 billion worth of funding from the government’s Biomedical Advanced Research and Development Authority (BARDA), getting a vaccine through human trials isn’t easy. Large-scale testing must show a vaccine is both safe and can actually provide immunity against the SARS-CoV-2 virus that causes COVID-19.

Verywell talked to Jerome Custers, Senior Scientific Director of Vaccine Research at Johnson & Johnson, to learn what the process involves and what will make human trials successful.

Markers of Success

The most important parameter in a human trial, according to Custers, is safety. 

“In our first clinical trial, we will vaccinate healthy adults, and those people will be monitored very strictly for safety,” Custers says. “In addition to that, we’re looking to see if our vaccine is able to induce a strong immune response and produce antibodies against the coronavirus.”

Custers says antibodies can be measured from blood samples. Researchers will take blood samples from trial participants before they are given the vaccine, a week or two after vaccination, and then at regular intervals after that. 

“We have data from animals—monkeys, mice, and hamsters—that confirmed what we thought we would see and are encouraging us to continue in this direction.”

Creating and Testing a Vaccine

The direction Custers refers to is the use of something called AdVac technology. Using this vaccine platform, Johnson & Johnson scientists remove a piece of the genetic sequence from the adenovirus, which causes the common cold. Then, they insert genetic code from COVID-19.

Johnson & Johnson has used the same AdVac platform to develop vaccines for Ebola, HIV, RSV, and Zika, which combined, have been trialed safely in over 50,000 people. With COVID-19, however, the company is trying to do it on a much larger scale and a much more abbreviated timeline.

“A billion vaccines is still the goal,” Custers says. 

While the first in-human clinical trials were initially slated for September, the company announced on June 10 that it would bump them up to the second half of July. This phase, considered a Phase 1/2a clinical trial, will involve 1,045 volunteers. Typically, this takes several months to years. But Johnson & Johnson is already looking ahead to Phase 3, which Moderna and AstraZeneca plan to enter this summer. 

“We are thinking that Phase 3 trials will include several tens of thousands of people,” Custers says. “But that will largely depend on how that pandemic develops. The incident rate of infection is going down.”

Currently, Phase 1/2a clinical trials are planned to take place in the U.S. and Belgium. Belgium has seen a steady decline in confirmed COVID-19 cases since April, when cases peaked at over 2,000 on a single day. Throughout the month of June, new cases hovered around 100 per day. 

“Of course, we are happy that’s happening, but it will also make showing that the vaccine can prevent infection much more difficult,” Custers says. “You need a certain incidence rate to be able to do that.”

Custers says that, if needed, Johnson & Johnson could move testing to areas where infection rates are still high. 

“It’s very hard to assess what the situation will be like in a couple months when we actually need to decide,” Custers says. “We’re monitoring the situation. We think it will be a potential issue for all the COVID-19 vaccines in development.” 

Learning From Other Vaccines

In addition to the vaccines receiving BARDA funding in the US, there are approximately 140 COVID-19 vaccines in development around the world. Custers explains the race for a vaccine isn’t a competition—it’s a collaboration. 

“No one knows who will be successful, so it’s important for the world to have multiple shots on goal, as we tend to say,” he says. “It’s also important because we learn from each other. We’re all in different stages and have slightly different approaches. The data we generate—in preclinical data, animal studies, and clinical studies—will enable all of us to move as quickly as possible.”

Timeline Challenges

While Johnson & Johnson and other biopharmaceutical companies are working as quickly as possible to create a usable vaccine, a definitive timeline is still impossible to give. 

Custers says a number of factors influence timing. “Will the vaccines currently in development be successful?” he says. “Will we be able to show those vaccines work—is the COVID-19 incidence somewhere in the world high enough to be able to show the vaccine can protect people sufficiently?”

Even if both of those answers are yes, the scale of production is another challenge. 

“We need to make a sufficient amount of vaccine,” Custers says. “At the beginning, there won’t be enough of the vaccine to offer it to the general public. I imagine healthcare workers and people at an increased risk of contracting COVID-19 will get the vaccine first. It’s not really up to us as a company.” 

Custers says his team is working hard to meet these supply demands.

“We are doing things in parallel. Manufacturing is ongoing, and we’re upscaling to be able to make as many vaccine doses as soon as possible,” he says. “Usually, you only do that when you know the vaccine is working.”

He says that while much remains uncertain, Johnson & Johnson is optimistic about their vaccine candidate. 

“It’s very rewarding and motivating to work on this vaccine and be able to contribute something,” he says. “It’s a once in a lifetime opportunity—hopefully.”

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