A zoster vaccine is a vaccine that reduces the incidence of herpes zoster (shingles), a disease caused by reactivation of the varicella zoster virus (VZV), which is also responsible for chickenpox. Shingles provokes a painful rash with blisters, and can be followed by chronic pain (postherpetic neuralgia), as well as other complications. Older people are more often affected, as are people with weakened immune systems (immunosuppression). Both shingles and postherpetic neuralgia can be prevented by vaccination.