A New Type Of COVID-19 Vaccine Could Debut Soon

Jun 6, 2021
Originally published on June 7, 2021 8:17 pm

A new kind of COVID-19 vaccine could be available as soon as this summer.

It's what's known as a protein subunit vaccine. It works somewhat differently from the current crop of vaccines authorized for use in the U.S. but is based on a well-understood technology and doesn't require special refrigeration.

In general, vaccines work by showing people's immune systems something that looks like the virus but really isn't. Consider it an advance warning; if the real virus ever turns up, the immune system is ready to try to squelch it.

In the case of the coronavirus, that "something" is one of the proteins in the virus — the spike protein.

The vaccines made by Johnson & Johnson, Moderna and Pfizer contain genetic instructions for the spike protein, and it's up to the cells in our bodies to make the protein itself.

The first protein subunit COVID-19 vaccine to become available will likely come from the biotech company, Novavax. In contrast to the three vaccines already authorized in the U.S., it contains the spike protein itself — no need to make it, it's already made — along with an adjuvant that enhances the immune system's response, to make the vaccine even more protective.

Protein subunit vaccines made this way have been around for a while. There are vaccines on the market for hepatitis B and pertussis based on this technology.

A large test of the Novavax COVID-19 vaccine's effectiveness, conducted in tens of thousands of volunteers in the United States and Mexico, is about to wrap up. Dr. Gregory Glenn, president of research and development for Novavax, told an audience at a recent webinar hosted by the International Society for Vaccines that "we anticipate filing for authorization in the U.K., U.S. and Europe in the third quarter."

Turning plants into factories

To make the virus protein, Novavax uses giant vats of cells grown in the lab. But there's another way to make the protein: Get plants in a greenhouse to do it.

That's the approach being used by the Canadian biotech firm Medicago.

The plants used are related to the tobacco plant, and have been modified to contain the genetic instructions to make the viral protein.

The plants do something very valuable — they make a lipid shell that surrounds a bunch of the viral proteins, with the proteins sticking out.

"The plant will assemble the protein in a shape and form that is looking like the virus," says Nathalie Landry, Medicago's executive vice president for scientific and medical affairs. "So, if you look at an image of it, it looks like a virus, but it cannot induce any disease. But when [it's] injected as a vaccine your body will raise a good immune response."

Early studies suggest Medicago's candidate vaccine does just that, and the company is confident enough in those findings that it's already begun a large study in people that could involve as many as 30,000 volunteers in 11 countries.

Landry acknowledges that development of the Medicago COVID-19 vaccine has lagged behind others.

"We're a latecomer, but we're coming," she says.

Another latecomer that's coming is the pharmaceutical giant Sanofi. Its protein subunit vaccine against the coronavirus is also grown in cells in the lab.

Late last year the company was getting ready to mount a large study of the vaccine's effectiveness when the early results in a smaller group of people showed it did not seem to be inducing the immune response that would be protective.

"Especially in elderly individuals in that study, it was not as immunogenic as it should be," says Dr. Paul Goepfert at the University of Alabama at Birmingham, who was one of the researchers involved in those early studies. He says the issue turned out to be an incorrect calculation of the dose of vaccine being delivered.

"So instead of giving 10 micrograms of the dose, they were actually giving one microgram," Goepfert says.

Sanofi has fixed that problem and repeated the early studies with good results. The company is now enrolling volunteers in a large efficacy trial.

Goepfert says it'll be a good thing if all these vaccines make it to consumers. But that alone isn't going to solve the problem of getting people vaccinated.

Why? "Because the vaccines that we have now are just beyond our wildest dreams kind of effective," he says. "And I'm living in a state right now where it just frustrates me how slow our vaccine uptake is."

Goepfert lives in Alabama. According to the latest numbers from the Centers for Disease Control and Prevention, only Mississippi has a lower per capita rate of vaccination.

Copyright 2021 NPR. To see more, visit https://www.npr.org.

MARY LOUISE KELLY, HOST:

A new kind of COVID-19 vaccine could be available as soon as this summer. And as NPR science correspondent Joe Palca reports, the new vaccine has some advantages over what is currently available.

JOE PALCA, BYLINE: Vaccines work by showing people's immune systems something that looks like a virus but really isn't. If the real virus ever turns up, the immune system will be ready. In the case of the coronavirus, that something is a bit of the virus called the spike protein. The vaccines available now inject the genetic instructions for the spike protein into our bodies, and our own cells make the protein.

The vaccine soon to be available from the biotech company Novavax is different. It contains the spike protein itself. No need to make it - it's made. Gregory Glenn is president of research and development for Novavax. At a recent webinar hosted by the International Society for Vaccines, Glenn said a large study of the new vaccine is nearly complete.

(SOUNDBITE OF ARCHIVED RECORDING)

GREGORY GLENN: And we anticipate filing for authorization in the U.K., U.S. and Europe in the third quarter.

PALCA: The advantage of the type of vaccines Novavax makes is they've been around for a while. There are vaccines using the same approach on the market for hepatitis B and pertussis. What's more, they don't require special refrigeration, and they tend to work in people with weakened immune systems. Another advantage, Glenn says, is it's relatively easy to construct different versions of the vaccine in response to variants.

(SOUNDBITE OF ARCHIVED RECORDING)

GLENN: We have new constructs representing really pretty much every one of the variants that are out there.

PALCA: Now, to make the virus protein, Novavax uses giant vats of cells grown in the lab. But there's another way to make the protein. Get plants in a greenhouse to do it. That's the approach being used by the Canadian biotech firm Medicago. The plants are relatives of the tobacco plant that are modified to contain the genetic instructions to make the viral protein. Medicago's vice president for scientific and medical affairs, Nathalie Landry, says plants do something very valuable as they produce the viral protein.

NATHALIE LANDRY: The plant will assemble the protein in a shape and form that is looking like the virus. So if you look at an image of it, it looks like a virus, but it cannot induce any disease. But when injected as a vaccine, your body will raise a good immune response.

PALCA: Early studies suggest the vaccine does just that, and the company is confident enough it will have a successful vaccine that it's begun a large study that could involve as many as 30,000 volunteers in 11 countries.

LANDRY: So we can get approval of the vaccine and start delivering doses to the Canadian government. So we're a latecomer, but we're coming.

PALCA: Another latecomer that's coming is the pharmaceutical giant Sanofi. They have a spike-protein-based vaccine that's also grown in cells in the lab. Late last year, the company was getting ready to mount a large efficacy trial when early results showed the vaccine wasn't quite inducing the desired immune response.

PAUL GOEPFERT: Especially in elderly individuals in that study, it was not as immunogenic as it should be.

PALCA: Paul Goepfert at the University of Alabama, Birmingham was one of the researchers involved in those early studies of the vaccine. He says the issue turned out to be an incorrect calculation of the dose of the vaccine being delivered.

GOEPFERT: So instead of giving 10 micrograms of a dose, they were actually giving one microgram of a dose.

PALCA: Sanofi has fixed the problem and repeated the early studies with good results. The company announced it's begun enrolling volunteers in a large efficacy trial. Goepfert says it'll be a good thing if all these vaccines make it to consumers, but that alone isn't going to solve the problem of getting people vaccinated in this country.

GOEPFERT: Because the vaccines we have now are just beyond-our-wildest-dreams kind of effective - and I'm living in a state now where it just frustrates me how slow our vaccine uptake is.

PALCA: That state is Alabama. According to the latest numbers from the Centers for Disease Control and Prevention, only Mississippi has a lower per capita vaccine uptake.

Joe Palca, NPR News. Transcript provided by NPR, Copyright NPR.