they could get it into human trials and find out its worthless and have to start all over again.

the problem with getting a good vaccine is that its really really hard to get one that can pass through the membranes to the nerve ganglia in the spinal cord which is exactly where herpes likes to sequester itself. Its just that whole blood/brain barrier that makes it really hard. If it werent for this, there'd probably be no reason for a cure as the bodies immune system quite effectively attacks it when it wakes out of dormancy and expresses itself on the skin.

this is why outbreaks dont really last that long after the initial outbreak, we have antibodies that attack it very effectively. It just retreats into the nervous system where those specific antibodies cant get to it….and vaccines are based off of inactivated viral particles most often…which helps the body to make antibodies BEFORE initial infection occurs.