New and Old Ways to Make Flu Vaccines

Chances are, the vaccine for annual flu shots was made in the small Pennsylvania town of Swiftwater. It is home to the biggest flu vaccine plant in the country.

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And I'm Renee Montagne.

Today in Your Health, new and old ways to make vaccines. If you've gotten your annual flu shot, chances are it was manufactured in a small Pennsylvania town called Swiftwater. That's home to the biggest flu vaccine plant in the country.

NPR's Nell Greenfieldboyce recently toured a new addition that will triple the plant's capacity, and she saw a lot of something that you might be eating for breakfast.

NELL GREENFIELDBOYCE: What I saw was eggs - white chicken eggs. For decades, vaccine makers have used eggs as little factories to grow the virus. You might think that the people who work here would stop seeing eggs as food.

Dr. SAM LEE (Sanofi Pasteur): Actually, I enjoy eating eggs. I enjoy eggs in all aspects.

GREENFIELDBOYCE: Sam Lee works for Sanofi Pasteur, the company that built this new facility. From the outside, it looks like a corporate office building, but inside it generates the bulk vaccine that gets put in those little vials. Lee says the concentrated fluid shines. It looks opalescent.

Dr. LEE: It's actually more of a cream opalescence.

GREENFIELDBOYCE: It sounds kind of pretty.

Dr. LEE: Yes. Well, (unintelligible) for me, from a manufacturing standpoint, I enjoy looking at some rich fluid because it means I have a highly potent vaccine at that point.

GREENFIELDBOYCE: But before that, what he's got is eggs.

Mr. SHAWN HANES(ph) (Sanofi Pasteur): The area that we've just entered is normally very restricted.

GREENFIELDBOYCE: Sanofi employee Shawn Hanes is taking a tour group through an airlock and down a long hallway.

Mr. HANES: First stage of the process that you're going to see is inoculation. We're going to...

GREENFIELDBOYCE: The inoculation room has a machine that injects flu virus into the eggs using little needles. After being injected, the eggs go through big stainless steel doors into the incubators. These keep the eggs warm so flu virus can grow.

Unidentified Man #1: (Unintelligible) the other thing stopped.

GREENFIELDBOYCE: After a few days, they go through the harvesting machine. It slices off the top of each egg, then flips them over so the fluid drains out. This fluid gets pumped through various big tanks. The virus is killed, split, and purified.

Sam Lee says his company is thrilled to have this new addition, which will start making vaccines for next year's flu season. It will push Swiftwater's production capacity up to 150 million doses a year.

Dr. LEE: This facility is what we dreamed of.

GREENFIELDBOYCE: But even though everything is gleaming and state-of-the-art, the fundamental technology is based on chickens. So now Sanofi and other drug companies are developing alternatives.

Unidentified Man #2: Right now it doesn't look like much. A few piles of dirt, dump trucks, and back hoes.

GREENFIELDBOYCE: When a company called Novartis broke ground for a new flu vaccine plant in North Carolina, it was big news for the town of Holly Springs. The plant will brew up flu vaccine in huge vats of lab-grown cells.

Dr. ANTHONY FAUCI (National Institute of Allergy and Infectious Diseases): Clearly the future of influenza vaccine manufacture is cell-based as opposed to egg-based.

GREENFIELDBOYCE: Anthony Fauci is head of the National Institute of Allergy and Infectious Diseases. He says one advantage of a cell-based plant is that it can scale up production very quickly. It doesn't have to wait for chickens and roosters to do their thing.

Dr. FAUCI: If you have cells, you have them essentially there in storage and growing in vats. You just have those cells ready to go.

GREENFIELDBOYCE: That's attractive for officials who are planning for a flu pandemic - a dangerous epidemic that can occur when a new strain of flu appears. The federal government has shelled out over a billion dollars over the last few years to help vaccine companies transition to cell-based methods. But that will take time. So Fauci says pandemic planners are also boosting egg-based production.

Dr. FAUCI: We're projecting over 130 million doses that will be available for this flu season, which is the largest amount ever.

GREENFIELDBOYCE: Eventually the government wants to get closer to the 300 million doses this country would need during a flu emergency. And if a pandemic doesn't come, we'll just have lots of flu vaccine. That's fine by Fauci. He'd like to see lots more Americans getting an annual flu shot.

Nell Greenfieldboyce, NPR News.

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Comparing Flu Vaccines

Flu vaccines provide protection against the influenza virus by presenting the human body with something that looks like the flu virus but that does not cause disease. Our immune systems recognize this material and produce antibodies to it. If we are exposed to an actual flu virus, those antibodies will neutralize the virus and protect us.

Below, a look at the pros and cons of various vaccine production methods, either being used today or in development:

STANDARD VACCINE

Pros:

Millions of Americans receive this vaccine every year. It's safe and well tolerated. Its production begins in hens' eggs — a tried and true technology for 50 years.

Cons:

The production method requires a great deal of planning. Eggs must be ordered many months in advance, and millions of doses require millions of eggs. Also, egg-based production could be problematic for a pandemic strain of flu that develops from a bird virus. That bird virus could be deadly to the chickens needed to make eggs.

LIVE-ATTENUATED VACCINE

Pros:

This newer method of production results in a vaccine that has a flu virus that is crippled, so it can't cause disease. But the virus is not killed, as is the case in the standard vaccine. The vaccine also can be given as a nasal spray (FluMist is the brand name).

Cons:

More expensive than standard vaccine, and also produced in eggs. Not approved for young children or older people.

CELL-BASED VACCINE

Pros:

This vaccine can be produced in giant vats of living cells. Such a production method means it can be scaled up much faster than egg-based vaccines, making it more useful in a pandemic. Several versions have been tested successfully in people. Earlier this year, the European Union approved a seasonal flu vaccine grown in cell culture. It's called Optaflu and is manufactured by Novartis, which is building a manufacturing facility in North Carolina that will produce cell-based flu vaccines.

Cons: Won't be widely available for a few years. Clinical trials are under way, but no flu vaccine made this way is currently approved by the Food and Drug Administration.

DNA VACCINE

Pros: Instead of injecting flu virus proteins into people, this concept involves injecting just the DNA from a flu virus. Human cells then "read" this DNA and create proteins that act as a vaccine. Manufacture of DNA could be much faster than that of conventional vaccines.

Cons: The method is being tested in human clinical trials, but development could still take years, and it may not prove to be safe and effective.

UNIVERSAL VACCINE

Pros:

Scientists would like to develop a flu vaccine that can be given just once and last for life, as is the case for some childhood vaccines. Current vaccines have to be tailored to protect against specific strains of flu viruses. This one, ideally, would protect against them all.

Cons:

This is currently more a concept than an actual product, though scientists do have some strategies that could ultimately lead to a universal vaccine.

— By Richard Harris and Nell Greenfieldboyce

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