Cytomegalovirus Seroprevalence and 'Cytomegalovirus-Safe' Seropositive Blood Sonors

Cytomegalovirus (CMV) seroprevalence was determined in 9343 first-time New Zealand blood donors between 2003 and 2006. Of 39960 current seropositive donors the proportion testing seropositive more than 12 months previously was calculated. Overall, seroprevalence declined from 66·1 % [95% confidence interval (CI) 64·1-68·1] in 2003 to 60·6% (95% CI 58·5-62·6) in 2006. Nevertheless, thèse rates are significantly higher than the 47 % overall seroprevalence found in 1988 study. Seroprevalence was higher in females than maies and in older than in younger age groups in ail four years examined. Ethnicity appeared to be related to seroprevalence with the highest rates found in Pacific Islanders (93·2%) and the lowest in Caucasians (54·8%). At least 38242/39960 (95·7%) seropositive donors were found to have seroconverted more than 12 months previously. Recent evidence suggests that such 'remote' seroconverters may pose a much lower risk of transfusion-transmitted CMV infection than recently infected seroconverting, but seronegative, blood donors.