Study objective: Varicella, an illness common to children, can occur in nonimmune adults, often causing serious morbidity and mortality. House officers without protective titers to varicella are at risk of contracting the disease and may spread it to the patients they serve. They are also subject to significant losses in work time and wages. Accordingly, in August 1996, the Centers for Disease Control and Prevention recommended vaccinating nonimmune health care providers with the varicella vaccine. We also sought to document the seroprevalence of varicella antibodies among new house officers and to determine the association of self-reported history of infection with varicella antibody levels.
Methods: This study was conducted at a university-affiliated teaching hospital. Serology testing was performed on house officers beginning their residencies in July 1997. Subjects provided information regarding demographics, medical history, previous varicella exposure, and previous administration of varicella vaccine. Serum was tested using the FIAX test kit, (Biowhitaker, Walkersville, MD).
Results: One hundred fifty-four house officers participated. The mean age was 30 (range, 24 to 50+/-SD 5.5 years). History of varicella infection was given by 119 (77%) of the 154 subjects, whereas 15 (10%) reported no history of infection, and 20 (13%) were uncertain. Ten (7%) of the participants had received varicella vaccine previously. Overall, 6 (4%) had nonprotective titers to varicella. Of the 119 house officers who reported a history of varicella, only 2 (1.7%) had nonprotective titers, and 4 (27%) who reported no history of varicella infection had nonprotective titers. Of the 10 house officers who had previously received varicella vaccine, 1 (10%) had nonprotective titers.
Conclusion: Although most house officers had protective titers, a reported history of varicella or the administration of varicella vaccine did not assure the presence of protective titers. House officers should be tested for varicella immunity regardless of a history of previous infection or the administration of varicella vaccine.