The only way to discover whether new interventions are effective is to test them during an epidemic.
A virologist carrying out mouse experiments in a lab in Hamburg five years ago accidentally pricked her finger. The syringe contained the Zaire Ebola virus, the same strain wreaking havoc today in Guinea, Liberia and Sierra Leone. There is no approved treatment or vaccine for Ebola, or even one that has passed the first phase of safety trials in human volunteers. Yet unlike those exposed to Ebola in West Africa recently, the Hamburg virologist was quickly offered an experimental vaccine.
This vaccine hadn’t yet been tested on humans, but it had been shown to offer primates some protection against Ebola infections. For the virologist, it wasn’t a good option, but it was the only one available in the face of a virus with an extremely high mortality rate. She chose to take the vaccine.
We expect it is a risk we would take if one of us were exposed to Ebola. The Hamburg researcher didn’t fall ill. It is unclear exactly how the vaccine worked, or indeed whether she was ever infected. What is important is that immediate access to an experimental vaccine allowed her to try something with the potential to protect her.
It is highly likely that if Ebola were now spreading in Western countries, public-health authorities would give at-risk patients access to experimental drugs or vaccines. Indeed, there are reports that two U.S. relief workers infected with Ebola in Liberia have been offered experimental therapies, which they have accepted.