It's not about bacteria; it's about our reactions to them.
Treating acne is a $3 billion industry in the United States alone. That may be why there's not enormous incentive to develop a vaccine. Like the rest of medicine, though, the approach to acne is now becoming more individualized -- taking into consideration differences in the way different people respond to the disease.
Some acne 101: You may already know that acne is linked to the bacterium Propionibacterium acnes, which nestles in the dark, oily, oxygen-deprived crannies of our pores. Acne is also linked to inflammation, overgrowth of the upper skin layer, excess sebum, and depression. Because the root of the problem has long seemed to be a bacterium, antibiotics have been the go-to treatment. Dermatologists are also working on developing something called "antimicrobial peptides" to kill the bacteria -- anticipating the day that the bacteria outgrow our current antibiotics, and they fail us.
For the rest of the story: http://www.theatlantic.com/health/archive/2013/06/why-does-acne-still-exist/276477/