On August 24 2024, Xiaoshan District Center for Disease Control and Prevention, Hangzhou City, received a report of two cases of varicella infection among staff in the intensive care unit (ICU) of a hospital in its jurisdiction. The center immediately organized personnel to conduct an epidemiological investigation of the cases and their close contacts. The index case was a patient admitted to the ICU who had large areas of red rash and pustules on the chest, back, and right axilla. This case was diagnosed with herpes zoster by a dermatology consultation within the hospital. The other nine secondary cases were all nursing staff in the ICU, who were clinically diagnosed with varicella between August 21 and September 1, with an attack rate of 14.06%. All secondary varicella cases had a history of contact with the herpes zoster case and no history of varicella infection. Their varicella vaccination history was unknown. Based on the results of the on-site epidemiological and sanitary investigations, it was determined that this was an outbreak of varicella in the hospital caused by a herpes zoster case. After the last case was diagnosed, no new cases were reported within the longest incubation period (21 days), and the outbreak was declared over on September 21. Close contact with the herpes zoster case was likely the main cause of the outbreak. This highlights the need for early identification and isolation of suspected herpes zoster cases in hospitals in the future, as well as enhanced protective measures to prevent nosocomial infections.