[To make a vaccine] you first need to make a decision as to what approach you want to take. Then you have to do extensive animal model testing to make sure that the approach that you’ve taken is safe in animals, and that it induces an immune response which would likely be protective. Then you gradually do studies in people to make sure it’s safe, and then to make sure that it induces an immune response. That takes time, a lot of time, typically years. Then and only then, are you ready to put it into people to see whether or not it works in an outbreak situation.