Continuous cytomegalovirus seroconversion in a large group of healthy blood donors

Background and Objectives: Transmission of cytomegalovirus (CMV) to seronegative, immunocompromised recipients can cause serious and fatal complications. Although the seroprevalence of CMV is high, the risk of primary CMV infection among healthy blood donors has not yet been analysed in a large population. Materials and Methods: We developed an algorithm to determine the rate of CMV seroconversion in an overall cohort of 24 260 subjects who donated 176 474 blood units during an 11-year observation period. Results: We detected CMV seroconversion in all relevant age groups (18-60 years) with an overall seroconversion rate of 0.55% per year. Both CMV seroconversion and seroprevalence occurred more frequently in female donors (P = 0.02 and P < 0.001, respectively). We identified 30-35-year-old blood donors as the group with the highest rate of CMV seroconversion per year (1.33% vs. 0.46%; P < 0.0001). Conclusions: We conclude that the risk of primary CMV infection is a continuous life-long event and correlates with age and female gender.