Army scientists hope their COVID-19 vaccine will be a universal booster shot

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Army scientists are testing whether their new COVID-19 vaccine candidate, which entered human trials this week, can serve as a universal booster shot for all other available coronavirus vaccines.

Nearly 20% of Americans have already been fully vaccinated against COVID-19 using one of three authorized vaccines.

But with public health experts and government officials anticipating the need for booster shots down the line, scientists at the Walter Reed Army Institute of Research are examining whether their vaccine candidate can “mix and match” with the others to enhance and prolong protection.

The Walter Reed vaccine — called SpFN — may boost the duration and breadth of immune responses in combination with other vaccines, which are made using different technologies, Dr. Kayvon Modjarrad, director of Walter Reed’s Emerging Infectious Diseases Branch, said in an interview with McClatchy on Thursday.

“This is something that we actually started planning before the whole field started looking at this, but the rest of the field of SARS-CoV-2 vaccine development is now coming to look at these issues as well,” Modjarrad said, using the technical term for the novel coronavirus.

“We think this vaccine also has utility as a booster for another type of vaccine, in addition to its role as a stand-alone vaccine,” he said, referring to the Walter Reed vaccine candidate.

Mixing and matching different vaccines has been an area of “intense investigation” for vaccine researchers over many years, Modjarrad added. But it has never been implemented before.

Two COVID-19 vaccines currently authorized by the Food and Drug Administration for emergency use — produced by Pfizer-BioNTech and Moderna — use messenger RNA technology, known as mRNA, which teaches human cells how to make proteins that trigger an immune response.

A third FDA-authorized vaccine for emergency use, produced by Johnson & Johnson, uses viral vector technology with which a harmless virus becomes a courier to provide cells with instructions to prepare an immune response. AstraZeneca, which also uses that technology, has submitted data on its vaccine to the FDA for review.

The Water Reed vaccine differs from those vaccines. It injects ready-made, multifaceted proteins into the body which may be able to prepare the immune system for different variants and strains of coronaviruses at once.

“When you look to other fields, like HIV or influenza, we’ve learned a lot from the research on those viruses,” Modjarrad said.

“And what we’ve seen is that when you start with a vaccine that is like a genetic vaccine — DNA, mRNA — or a virus vector, and then you come in and you boost with a protein, you get a stronger response, a longer response and a broader response, rather than coming in with the same platform,” he said.

After months of studying their vaccine candidate in different animals, Walter Reed scientists began their clinical trial in humans on Tuesday. Four volunteer participants were injected with the vaccine in the first two days. After initial observation of these individuals, the first phase of the trial will expand to 72 people, and initial results are expected mid-summer.

Dr. Paul Scott, deputy director of the Emerging Infectious Diseases Branch, who is overseeing the trial, said the testing phase of the vaccine found it “provided broad, potent protection in animal studies.”

“The trial is going well so far, and we have a very diverse group of volunteers including one active duty military and one retiree,” Scott said in an email. “Safety is key at this early stage, so we will follow these first volunteers closely for a week to ensure safety before we continue enrolling the study, and then we will continue to follow all volunteers for safety throughout the entire period of the study.”

Modjarrad’s team designed SpFN to be a highly adaptable vaccine that can address multiple variants of the pandemic coronavirus in a single shot, and potentially provide protection against past and future coronaviruses.

The Army lab, at the same time, is researching whether its vaccine candidate can be used as a stand-alone vaccine and a booster, Modjarrad said.

“Speed is everything, so everything is being done in parallel,” he said. “We’re addressing the questions of this vaccine being used as a booster at the same time that we’re addressing the question of this vaccine being used on its own.”

Modjarrad has briefed Defense Department leadership and the federal COVID-19 response team on the vaccine’s profile for safety and effectiveness based on animal trials. They have expressed eagerness for the future findings from human trials, he said.

“I think this is a great week for us, but also for the U.S. military and global health, because this vaccine is not a repetition of other vaccines. We have always been positioning this vaccine to be a next-generation product that is thinking toward the future,” Modjarrad said. “This is what we’ve been working towards for the past year.”

Updates with comments from Dr. Scott.