The Rise of a New Smallpox Vaccine

Reuters is reporting that the US Strategic National Stockpile will begin acquisition of a new smallpox vaccine.  The new product, Imvamune, promises reduced side-effects and potentially improved protection for patients who are treated after exposure to the virus.  These traits could make the vaccine much more effective as a countermeasure against a biological attack using smallpox.

Though the story of Imvamune ultimately demonstrates that improved countermeasures to biological threats can be developed, the story also illustrates some of the challenges involved in the process.

Reducing Side Effects

Though vaccination campaigns eradicated smallpox, the existing vaccine uses a live virus that can cause significant or even life-threatening complications.  This risk was deemed acceptable in the effort to eliminate the threat of one of the deadliest infectious diseases in history, but would be far less acceptable as a defense against a hypothetical attack in the post-smallpox world.

With this in mind, a Dutch company called Bavarian Nordic worked to reduce the dangers associated with the vaccine by weakening, or attenuating, the virus.  The manufacturer’s claims indicate that the new vaccine strain cannot replicate in humans, making it safe for use in patients who are immunocompromised or otherwise unable to tolerate the previous vaccines.  They also cite animal studies suggesting that the vaccine will protect people after exposure to the virus – a crucial trait in a biodefense countermeasure that might be administered only after an attack is believed to have occurred.

Challenges of Developing Countermeasures

Paul Chaplin, Executive VP for Research and Development and CSO at Bavarian Nordic, spoke at the 2010 BIO convention, which we covered two weeks ago.  He said that the company was motivated to begin the work when they saw the US government stockpiling the old smallpox vaccine, despite its limitations; Bavarian believed that they could find a market by overcoming these issues.  However, he also noted the significant challenges associated with these kinds of efforts.

Bavarian took three years to build the plant that will produce the new vaccine, and will likely be unable to ever use the facility for any other product due to the difficulty of demonstrating that the production line is completely free of the virus.  This expense was necessary because the uncertain size of the market for biological countermeasures – which will only be needed in the event of an attack – makes it difficult for companies to establish commercial partnerships with other companies that might have the capacity to manufacture a vaccine.

Chaplin stated that industry has a role in developing responses to threats identified by governments, but called for greater commitments to ensure that investment in these areas remains economically viable.  In an era of financial crisis, however, it is unclear to what extent governments can make such commitments.

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