Exposure with Minor Risk Factors among Blood Donors in Tehran Province, Iran: A Cohort Study

For screening and selecting healthy volunteer blood donors, it is important how to face with the minor risk factors. In a cohort study during the 2005-2011, minor risk factors for transmission of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) among blood donors in Tehran, Iran, were evaluated. Data for the study were obtained from the database of MAK-SYSTEM International Group. Odds ratio and relative risk were calculated. To calculate the incidence among repeated donors, the number of seroconverters was divided to person-years at risk. From 19,044 blood donor volunteers entered the study in 2005, 10,696 people were in the unexposed group (no risk) and 8,348 in exposed group to the minor risk factors. They were followed until 2011. The odds ratio was 2.7 for donors exposed group and 2.9 in cupping, 1.4 in dentistry, 1.5 in endoscopic plus biopsy, and 7.8 in household subgroups. Calculated relative risk for HBV was 6.9 in exposed group to the minor risk factors and 9.9 in cupping subgroup. The results of this study show while in the country, more accurate screening tests such as nucleic acid-based tests (NAT) or polymerase chain reaction (PCR) methods has not been used routinely for blood donors, deferral strategy applying in cases of exposure to minor risk factors, especially in the cupping exposed cases, is essential.