At first, the results of the AIDS vaccine study in Thailand sounded very promising, but later reports seem to downplay its effectiveness.
Originally, most experts thought that study wouldn’t show any effects at all, so it was a positive surprise when the data did show an effect. What that data is telling us is the probability that there was an effect and there are different ways to look at the data—in some cases it looks like the probability was greater than 95 percent and in some cases like it was less than that.
That discussion shouldn’t confuse people about the fact that this study was a valuable step forward. Understanding what happened in the immune systems of people who were protected is likely to give us clues about where we should go next. But even with the most positive view of this study, no one would say that this is a vaccine that we should go and use widely.
As for how long it will be before we have a viable vaccine, it’s definitely taken a lot longer than we first expected. But we do have much deeper insights today so I’m a firm believer that given enough time, we’ll find the answer.