Susceptibility to varicella virus of certain adults in the southeastern United States.

The serologic status of 76 adults was determined to evaluate their immunity to the varicella virus. Previous reports indicate that 92% to 98% of the adult population develop this immunity. Our experience with nosocomial varicella infection in two hospital employees suggested that more adults in this subtropical region may be susceptible to varicella infection. Three (7.1%) adults with a definite history of varicella had a positive indirect fluorescent antibody (IFA) test. Twenty-eight (72%) of 39 employees without a history had a positive serology, a rate lower than previously reported (p less than 0.002). Twenty-nine (85%) of 34 other adults and 60 (79%) of the 76 adults tested had positive tests; these rates are also lower than reported (p = 0.003 and less than 0.001, respectively). These data indicate that some adult groups may be more susceptible to varicella infection and suggest that knowledge of immunity should be an important health concern in some hospitals.