Hospital infection control for varicella zoster virus infection.

More than 500 hospital employees and 209 patients were exposed to varicella zoster virus (VZV) as a consequence of 22 uncontrolled hospital introductions that occurred over a period of 34 months. Five introductions of varicella were by hospital employees who acquired the infection outside the hospital. Successful infection control of VZV requires an accurate definition of the susceptible population and the limitation of transmission. Individuals with prior VZV infection are epidemiologically not at risk for developing clinical illness. Serologic screening of hospital employees with uncertain prior VZV history is effective in identifying those at risk of developing the infection. A prior history of intimate exposure to VZV does not imply immunity in the absence of clinical illness.