Results of a rubella screening program for hospital employees: a five-year review (1986-1990)

The Barnes Hospital Employee Health Service (St. Louis, Missouri) rubella screening program was evaluated over the 5-year period between January 1, 1986, and December 31, 1990. A total of 6,969 new employees were hired, and 6,115 (87.7%) were screened for evidence of rubella immunity by the Employee Health Service. Rubella serology was performed on 5,893 (96.4%) of the screened employees, while 222 (3.6%) had documentation of prior rubella vaccination or rubella infection. The absence of immunity was identified in 325 employees or 5.3% of all those screened. Women were more frequently screened by the Employee Health Service than were men (p < 0.0001), and blacks were more frequently screened than were non-Hispanic Caucasians (p < 0.0001). Physicians were less frequently screened than were other departmental groups (p < 0.0001). The rate of seronegativity for each year of hire varied from 4.45 to 6.76%, but these differences were not significant. Logistic regression analysis demonstrated that 5-year birth cohorts correlated significantly with serologic status. Employees born in 1960-1964 were least likely to be seronegative, and employees born in 1970 or later were most likely to be seronegative. Sex, race, and department group were not predictive of serologic status, although significant differences in results from different rubella assays were detected. Only 13.8% of seronegative employees were subsequently vaccinated by the Employee Health Service. This study demonstrates a lower seronegativity rate than did previous studies. It identifies groups of employees likely to escape rubella screening and low vaccination rates. It finds increasing seronegativity among employees born after 1964 that correlates with the reported increasing rates of rubella in the United States.