May 19th, 2009
01:49 PM ET

Possible swine flu vaccine whipping around the world

By Caleb Hellerman
CNN Medical Senior Producer

I’d just gotten the kids to bed and was cleaning up the house when the news flashed on my BlackBerry – a Chinese news report that researchers in South Korea, working with a sample from Atlanta, had discovered a potential vaccine against the swine flu H1N1 virus. It was nearly 10 o’clock at night but that’s how this goes – a worldwide, round-the-clock effort for the past several weeks, what some are calling a model of international cooperation.

A few minutes later I was on the phone with Dr. Seo Sang-heui, of Chungnam National University. He told me that yes, he believes he has created a vaccine that could be used against the virus. He’s packed up eight vials of the new vaccine and was waiting for a courier to pick them up and fly them to Atlanta, for testing at the CDC. He figured the courier would arrive in about an hour.

We’re not talking about a usable vaccine, not yet, but this is an important step. Here’s how it works: the U.S. Centers for Disease Control and Prevention isolated the 2009 H1N1 virus in its lab, in Atlanta. It sent isolates to a number of researchers around the world – including, it appears, Dr. Seo. These researchers follow a careful regimen, genetically modifying the vaccine to make it grow well, while keeping the traits that will – we hope – induce a strong immune response. It’s a process of trial and error, but Dr. Seo told me that in the past few days he figured out a way to grow the modified virus in an agar solution. He says he’s doing what any vaccine researcher would do, sending the samples back to Atlanta at no charge, with no conditions attached.

CDC spokesman David Daigle told us that he wasn’t aware of the finding — yet. But assuming the samples do arrive, they’ll go straight to the CDC laboratory for genetic analysis. That’ll tell us, one way or the other, if this is really a potential vaccine. Dr. Gupta and I were at the lab just two weeks ago, peering through the window where scientists were tinkering with the swine flu virus under stainless steel hoods that provide special ventilation, keeping the virus from floating around the room and out the door. The hoods look a bit like big fans over a stove, except for a glass front that lets the researchers see what their hands are doing.

Assuming this finding is the real deal, samples of the candidate vaccine will be shipped to manufacturers around the world. These companies have to adapt the material to their own processes. They have to make sure the vaccine grows well in eggs. Yes, chicken eggs. They have to test various mixtures, to see how well it grows and also whether the vaccine produces a strong immune response in animals, probably mice. They’ll want to see if additives – “adjuvants” – can enable them to produce an immune response using less vaccine – an important consideration if there’s limited supply, and we want to inoculate a billion people. At least one company, GlaxoSmithKine (GSK), says it’s already received notices from several governments that they intend to purchase mass quantities of vaccine, once available. According to GSK, Great Britain has pre-ordered 60 million doses and France, 50 million.

If the vaccine works in animal testing, they’ll test it in people. If that works – and seems to be safe – it’s up to regulators – the Food and Drug Administration, in the U.S. – to give the thumbs-up. If all goes well, the first doses could reach the public in anywhere from four to six months. Of course, the U.S. and other governments might not order mass quantities of H1N1 vaccine. There’s a limited number of eggs, and depending on the final formula, buying more H1N1 vaccine might mean producing less of the seasonal flu vaccine. We’ll be following this closely over the next few months.

There’s a long way to go, from Seoul to a pharmacy near you. And keep in mind, there may be other candidate vaccines discovered. But if the finding we hear about last night is confirmed, it’s a pretty big step. A new strain of influenza can be a scary thing, and it will be a big relief if we have an effective vaccine before the next flu season hits.

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