SAN DIEGO – After funding was discontinued for individual donation (ID) nucleic acid testing (NAT) of blood donations, the risk of transfusion-related infections in Denmark increased. But according to new findings presented here at the American Association of Blood Banks annual meeting, that policy was short lived.
When ID NAT was removed from the screening process, the estimated increase in the risk for transfusion-transmitted HIV went from one in 80 years to one in 18 years; for hepatitis B virus (HBV), it went from one in 34 years to one in 17 years; and for hepatitis C virus (HCV), the risk increased from one in 250 years to one in 8 years.
“Between 2009 and 2016, we had 14 NAT reactive/seronegative cases among the repeat donors, and one was due to an acute hepatitis C infection,” said study author Leen Baudewijn, MD, of Odense (Denmark) University Hospital. “This would have been missed without NAT testing.”
Dr. Baudewijn explained that Denmark has since reversed this new policy. “The Danish government decided not to discontinue NAT because there were almost no savings,” she said during her presentation. “We had the extra costs for anti-HBc [anti-Hepatitis B core] testing for repeat donors, and extra cost due to mandatory NAT testing for plasma for manufacturing medicinal products. So it was not possible to abrogate NAT testing because of contracts with the industry.”
However, she added that “one of the most important reasons was that one of the vendors for NAT screening reduced the price substantially by 45%.”
The majority of industrialized countries have implemented the use of increasingly sensitive assays for screening donated blood, although to date, there is no technology that can guarantee zero-risk blood products. However, the risk for transmission of a viral infection via transfusion is low in Northern Europe.
But after a case of HIV infection linked to a blood transfusion occurred, Denmark mandated ID NAT in 2009 for serologic-based screening assays for HIV, HBV, and HCV. In July 2017, the government changed its policy and discontinued funding for ID NAT screening and, instead, mandated anti-Hepatitis B core screening be added to the serologic screening assays for repeat donors.
In this study, Dr. Baudewijn and her colleagues used an incidence/window model to estimate the residual risk (RR) of transfusion-transmitted viral infections after ID NAT was halted in Denmark. They estimated incidence rates for blood and plasma donations obtained from repeat donors during 2006-2016 based on the number of positive tests after a negative donation. The residual risk was estimated as the incidence rate multiplied by the average window period for HIV, HBV, and HCV, with and without ID NAT testing.
A total of 3.5 million donations were screened during the study’s time period, with donors averaging two blood donations per year. The researchers estimated the RR for each donation with and without ID NAT.
For HIV, the RR without ID NAT was 1/3,647,888 and with ID NAT it was 1/16,436,213; for HBV, those numbers were 1/3,352,628 without and 1/6,806,407 with; and for HCV, 1/1,573,213 without and 1/50,429,289, with.
The overall probability of missing an infectious red blood cell unit was 35/1,000 in a population of 6 million, Dr. Baudewijn noted.
The authors had no relevant financial disclosures
SOURCE: Baudewijn L et al. AABB 2017. Abstract P4-A03A.