帶狀疱疹是潛伏在人體的水痘帶狀疱疹病毒再活化所造成。兒童帶狀疱疹狀並不常見，未滿兩歲更是罕見。本個案為1歲11個月大的女孩，過去未長過水痘，滿一歲時曾打過活性減毒的水痘疫苗。接種後第348天，在施打疫苗的左大腿（第三及第四腰椎的神經皮節）長出帶狀疱疹。經Acyclovir治療後，恢復迅速。依此個案的病史和臨床特徵推測，其帶狀疱疹可能是水痘疫苗所造成。若想確認帶狀疱疹在曾打過水痘疫苗的病人身上，到底是野生株或疫苗株的病毒所造成，最好的方法是做PCR檢驗。根據研究，水痘疫苗的確可能造成帶狀疱疹，但有施打疫苗者，其發生率和症狀均低於未施打疫苗者。整體而言，施打水痘疫苗，不僅能預防水痘，亦能預防帶狀疱疹，施打兩劑保護力更好。

Herpes zoster, caused by reactivation of the varicella-zoster virus (VZV), is not commonly seen in children, especially in those under 2 years of age. We reported a case of a 23-month-old girl with herpes zoster. She had no personal history of chicken pox. She was immunized with the live attenuated varicella vaccine at 12 months of age. Nevertheless, she developed herpes zoster in the left thigh (L3-L4 dermatomes) around the immunization site 348 days after the varicella vaccination. Her clinical symptoms improved rapidly after acyclovir treatment. Based on the personal history and clinical presentation, it is possible that her herpes zoster was caused by the virus of varicella vaccine. The best way to identify wild-type or vaccine-strain VZV in a herpes zoster patient with a prior history of varicella vaccination is by viral genome detection using polymerase chain reaction (PCR). As previous studies indicate, vaccine-strain herpes zoster can occur after varicella vaccine. However, the incidence and symptoms of herpes zoster occur less often in vaccinated individuals than in unvaccinated ones. In general, varicella vaccine can prevent not only varicella but also herpes zoster. The preventive effect of two-dose varicella vaccination is better than that of one-dose vaccination.