Saturday, August 15, 2015

Developing Vaccines Against Rare Contagious Diseases

This month scientists announced that they now had a safe and effective vaccine against Ebola, the virus that caused a deadly epidemic in three African countries last year. But here's the irony; that same vaccine was shown to be effective in monkeys 10 years ago but then it was never tested fully in humans, and so it was not ready for widespread use in the latest outbreak.

How did this missed opportunity happen? Actually, it's an unintended consequence of how drugs are tested before they are approved for widespread human use. After a drug is shown to be effective (that is, it works against the intended disease or condition), it still must be tested for safety to prove that its benefits outweigh its potential harm. Testing for safety can involve thousands of subjects and can cost drug companies the better part of half a billion dollars. Drug companies are willing to undertake that expense for drugs to treat common, known conditions with lots of potential patients, such a heart disease or diabetes. But they're not willing to take the risk for a disease such as Ebola, which until the latest outbreak had been responsible for just a couple of minor outbreaks. From their perspective, what if they invested 500 million dollars in an Ebola vaccine and then there was never another Ebola outbreak?

The bottom line is that we can't expect drug companies to develop and test vaccines for rare contagious diseases on their own. Recognizing this, some scientists have suggested the creation of a global vaccine development fund of at least 2 billion dollars, to be funded jointly by contributions from governments, philanthropic agencies, and pharmaceutical companies. In all likelihood many of the vaccines might never be needed. It might sound like a waste of money to prepare for disease outbreaks that might never occur, but not compared to the total cost of another outbreak such as Ebola.

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