We prospectively studied day-care providers at six day-care centers in southeastern Iowa to determine their occupational risk for primary cytomegalovirus infection and to define epidemiologic risk factors. Ninety-six (38%) of 252 day-care providers were seropositive for cytomegalovirus by latex agglutination at entry into the study. Among 82 seronegative providers available for follow-up, seven seroconversions occurred at only two of the six participating centers, yielding an annualized seroconversion rate of 7.9%. Median time to seroconversion among these providers was 13 months. Using Kaplan-Meier estimates of risk, we determined that the overall risk of seroconversion among providers at various centers ranged from 0% to 22% by 12 months and from 0% to 40% by 16 months. Risk of cytomegalovirus acquisition by providers was independent of race, age, education, the presence of a child at home, or caring for children younger than 2 or 3 years in the day-care center. However, the risk of seroconversion among day-care providers appeared to parallel rates of cytomegalovirus excretion and acquisition among children at each center.
Murph JR, Baron JC, Brown CK, Ebelhack CL, Bale JF. The Occupational Risk of Cytomegalovirus Infection Among Day-care Providers. JAMA. 1991;265(5):603–608. doi:10.1001/jama.1991.03460050057020