Between Clementine and the vaccine? I'd have to say the vaccine... can go to hell. Seriously. It's worthless. It's certainly not worth the life of probably the coolest child ever.
Why is it worthless? Because it doesn't save anyone from anything they can't already prevent. It cures the zombie infection... So? The infection itself isn't fatal. Heck, it doesn't even do anything to hinder you. It simply kick-starts your corpse after you die. The vaccine doesn't do anything to stop that death. It doesn't suddenly end the zombies that are out there, so you still need to worry about being eaten. You just wouldn't have to destroy the brain after a death.
When all is said and done, the adaptability of humans would make the barbaric act (by current standards) of bashing, stabbing, shooting, whatever you do to destroy a brain not such a hard thing to accept in time. After years of dealing with this new rule of death, people would get used to it and accept it. If I know people, it may actually become a ritual, or tradition (like asking the father if he wants to cut the umbilical cord after a child is born) if humanity can survive that long. It would be little more than the new first step in the funeral process.
There's your vaccine right there. No expensive equipment. No complex formulas. No nonsense. Period. Destroy the brain, no zombie. Same thing.