Breakthrough infection by hepatitis B virus in a vaccinated blood donor: An emerging threat for transfusion safety in low‐endemic countries?

Abstract

We present the case of a breakthrough infection by hepatitis B virus (HBV), intending to warn about the challenge that HBV represents for transfusion safety. Virological markers for HBV infection were assayed during a blood donor screening by detection of HBsAg, anti‐HBc, and viral nucleic acid (HBV DNA) by a nucleic acid test (NAT). Additionally, samples were analyzed for detection of immunoglobulin M anti‐HBc, HBeAg, anti‐HBe, and anti‐HBs. A first‐time donor repeatedly tested positive for HBV DNA by NAT and nonreactive for HBV‐serological markers of infection. He stated having completed the anti‐HBV vaccination schedule; thus, study of anti‐Hbs resulted in reactive at protective level (18 mIU/mL). The donor denied clinical symptoms of hepatitis and remained healthy during the follow‐up period. 95 days postdonation, NAT was negative, seroconversion of anti‐HBc ab was detected, and a significant increase in anti‐HBs concentration was measured (>1000 mIU/mL). This is the first case of HBV‐breakthrough infection reported in Argentina and to our knowledge, this potential threat to transfusion safety is novel in an HBV low‐endemic region with high coverage of HBV vaccination. The occurrence of breakthrough infections challenges the current protocols for the identification of HBV‐infected subjects, could be a source of silent HBV transmission.