Risk of cytomegalovirus transmission by cryopreserved semen: a study of 635 semen samples from 231 donors

Background: The hypothetical responsibility of sperm donation in cytomegalovirus (CMV) transmission to recipients and precautions to prevent this transmission are widely discussed. The aim of this French CECOS Federation study was to evaluate both the reality and the importance of the CMV risk due to donor sperm and the relevance of measures used to screen it. Methods: We conducted a prospective multicentric study. CMV was detected by rapid and conventional cultures and by PCR in the frozen sperm of donors who met the normal criteria required of semen donors, irrespective of their CMV serological status. Results: 635 samples from 231 donors (39.4% IgG(+)) were obtained and tested by culture; 551 samples from 197 donors were also tested by PCR. From those samples, 0.78% were culture(+), 1.57% culture(+) and/or PCR+; 3.3% of seropositive donors and 0.12% of initially seronegative donors were culture(+), but in the latter seroconversion occurred during the quarantine period; of the 197 PCR-tested donors, 3.5% (6.2/1.7) were PCR+, 3.3% (5.3/1.45) culture(+) and/or PCR+. PCR+ samples can be culture(-) and vice versa. The most strongly positive sample corresponded to an initially seronegative donor. Conclusion: The best strategy to prevent potential CMV risk is to test donors for CMV IgG and IgM antibody at the outset and after a 6 month period of quarantine and to reject initially IgM seropositive donors or donors who seroconvert during the quarantine period.