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A new kind of COVID-19 vaccine is about to roll out around the world. It's called a protein subunit vaccine. Early on in the pandemic, many experts thought this was the kind of vaccine that would be most likely to succeed, and so far, it hasn't. NPR's Joe Palca has this story about why it's taken so long for these vaccines to be ready for distribution and why they're still needed.
JOE PALCA, BYLINE: When Operation Warp Speed began spending billions of dollars to facilitate the development of a COVID vaccine, it chose three vaccine technologies to back - mRNA vaccines being developed by Pfizer and Moderna, viral vector vaccines like Johnson & Johnson and protein subunit vaccines being made by Sanofi and Novavax. The first two technologies were successful, mRNA vaccines wildly successful, and there are now billions of vaccine doses in this country and around the world. A year ago, Novavax was confident its proteins subunit vaccine would also be out there. Here's Greg Glenn, Novavax president of research and development, in an interview we did in September last year.
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GREG GLENN: We have a massive number of people working on scaling up our vaccine. I am very optimistic by the end of the year we'll have a lot of product and, you know, we're talking about more than 2 billion doses in 2021.
PALCA: But Glenn's optimism was misguided. A large study of the vaccine took longer to complete than was hoped, and the company ran into manufacturing problems. Sanofi also stumbled with its protein subunit vaccine.
JULIE MCELRATH: I think we were assuming that the protein subunit vaccines would play a big role in accelerating development of a COVID vaccine.
PALCA: Julie McElrath directs the Vaccine and Infectious Disease Division at the Fred Hutchinson Cancer Research Center in Seattle. McElrath says she and her colleagues' confidence came because there were already subunit vaccines on the market for infectious diseases. This kind of vaccine works by injecting people with a tiny portion of the virus. In the case of the COVID-19 vaccine, just the so-called spike protein. Protein subunit vaccines tend to be very stable, so they don't require freezers for storage. A regular refrigerator is adequate. This makes distributing the vaccine to low-resource countries much easier. McElrath is convinced that subunit vaccines can still play a role in combating the pandemic.
MCELRATH: It's just that they're just a little further behind than the others.
PALCA: It might seem that the Novavax vaccine is arriving too late to make a difference. Ali Ellebedy is an immunologist at Washington University in St. Louis. He says you shouldn't think of the Novavax vaccine as a duplication of effort.
ALI ELLEBEDY: From a scientific perspective, it would be definitely great to have the subunit vaccine.
PALCA: Ellebedy primarily studies mRNA vaccines. He says these are new and scientists are still learning their strengths and weaknesses. To do that, it would be useful to have a large group of people vaccinated with a more familiar vaccine for comparison.
ELLEBEDY: Having multiple options is always a good idea.
PALCA: That day appears to be coming. Large studies of the vaccine have shown that it works extremely well, and so far, there are no safety concerns. Novavax has begun filing for emergency use authorization with various regulatory agencies. Silvia Taylor is vice president of global corporate affairs and investor relations for Novavax
SILVIA TAYLOR: We have filed for authorization all over the world, including in the U.K., Australia, Canada, New Zealand.
PALCA: These filings mean Novavax thinks it's licked its manufacturing problems because getting an authorization requires convincing regulators you can reliably produce the vaccine. Taylor expects the company will seek emergency use authorization in this country early next year. She says to boost manufacturing capacity the company has teamed up with several vaccine manufacturers, including the Serum Institute of India, the world's largest manufacturer of vaccines.
TAYLOR: So we have a tremendous amount of confidence that with everything we have learned over the past year, as well as the expertise of all of our partners, that we'll be in a great position to produce over 2 billion doses in 2022.
PALCA: That may sound familiar. Perhaps now it's achievable. Joe Palca, NPR News. Transcript provided by NPR, Copyright NPR.