Effectiveness of blood donor screening by HIV, HCV, HBV‐NAT assays, as well as HBsAg and anti‐HBc immunoassays in Germany (2008–2015)

Abstract

Background and ObjectivesIn Germany, in addition to standard blood donor screening, further mandatory tests were introduced for HCV‐RNA, HIV‐1‐RNA and for anti‐HBc. Screening for HBV‐DNA is optional. This study investigates the benefits of these additional tests for the detection of HIV, HCV, and HBV infections among German blood donors.Materials and MethodsFrom 2008 to 2015 we collected data on blood donations exclusively testing NAT positive (NAT yield) or reactive in only one of the screening assays. Assuming a Poisson distribution, we calculated NAT yield/reactive only rates on a per donation basis (number of yield/reactive only cases divided by the number of donations tested in the period under review) with 95% confidence intervals.ResultsResponding establishments covered 95% of the donations. We identified 20 HIV‐1‐NAT, 61 HCV‐NAT and 29 HBV‐NAT yield cases among approximately 46 million blood donations tested corresponding to 0·43 HIV‐1 NAT, 1·32 HCV‐NAT, and 0·64 HBV‐NAT yield cases per million blood donations tested. For one HBsAg reactive only case and 23 anti‐HBc reactive only cases in repeat donors, infection was confirmed by ID‐NAT which translates into 0·02 and 0·55 cases per million donations tested. During the 8‐year‐observation period, one HIV‐1, no HCV and four HBV transmissions associated with donations in the viremic pre‐seroconversion window period were reported.ConclusionAnnually, NAT screening alone detected 2·5 HIV‐1, 7·6 HCV, and 3·6 HBV infectious donations; anti‐HBc screening alone identified 2·9 infectious donations of repeat donors with occult HBV infection. Overall, the survey results support that the currently practiced donor HIV/HCV/HBV screening strategy in Germany does ensure a high standard of blood safety.

Detection of hepatitis B virus infection in German blood donors 2008–2015

“…Of the 51 participating BE, 45 270 111 donations were HBV‐NAT tested (92·8% of the donation volume in Germany) , 600 000 by ID‐NAT, otherwise by MP‐NAT. There were 29 NAT‐only cases (negative for HBsAg and anti‐HBc), 28 identified by MP‐NAT and one by ID‐NAT (Fig.…”

“…In comparison, the residual risk for HBsAg was 1:1 619 419 and 1:1 268 474 based on 41 HBsAg positive and anti‐HBc negatives derived from 34 look‐back reports for repeat donors and adjusted for first time donors by a factor of 1·2. The adjustment factor 1·2 was determined by dividing the NAT‐only yield rate among all donors (29/45 270 111) by the NAT‐only yield rate among repeat donors (22/42 101 203 ). The residual risk for ID‐NAT was estimated to range from 1:7 166 221 to 1:4 264 776.…”

“…Among the anti‐HBc positive/HBsAg negatives (Fig. ), 23 OBI cases were identified by supplementary ID‐NAT in repeat donors (42 101 203 ), within 3649 anti‐HBc “confirmed” positives. There were two other OBI reports for first‐time donors.…”

“…Data on HBV‐NAT‐only, HBsAg and anti‐HBc were collected as described previously : HBV‐NAT positive, HBsAg and anti‐HBc negative, that is, "NAT‐only". HBsAg positive, HBV‐NAT negative, in anti‐HBc positive as well as negative, if anti‐HBc negative referred to as "HBsAg‐only". Anti‐HBc and HBV‐NAT positive, HBsAg negative, that is, “occult HBV infection” (OBI). Information on the HBV‐NAT (limit of detection (LoD) and MP size) and HBsAg kit used, viral load and HBV genotype in NAT‐only, and recent HBV vaccination. …”

“…To review the current testing strategy for hepatitis B virus (HBV) in German blood donors, the Paul‐Ehrlich‐Institut (PEI) evaluated the yield of positive donations for HBV nucleic acid test (NAT) and hepatitis B surface antigen (HBsAg), as well as the benefit of antibody hepatitis B core antigen (anti‐HBc) screening for the period 2008–2015 . Since 10/2006, screening for anti‐HBc has been introduced in addition to HBsAg .…”