Breakthrough varicella infection in a healthcare worker despite immunity after varicella vaccination.

Although varicella vaccination is recommended for varicella- susceptible healthcare workers (HCWs), breakthrough infection after vaccination is not unusual, especially following household exposures. We report breakthrough varicella in a vaccinated HCW and review the data on breakthrough infection and concerns for the healthcare setting (Infect Control Hosp Epidemiol 1999;20:561-562). Varicella vaccination has been recommended for varicella-susceptible healthcare workers (HCWs). 1 However, studies of vaccination in adults have shown that 20% to 40% of adults with demonstrable antibody after vari- cella vaccination develop breakthrough varicella following household exposure to chickenpox. 2 We report an HCW who developed primary varicella, despite the presence of antibody following varicella vaccination. Although break- through varicella usually is mild, it raises questions for the