Residual transfusion risk of occult hepatitis B transmission associated to genotypes A and E among blood donors in Yaoundé, Cameroon.

backgroundOccult hepatitis B virus infection (OBI) poses a significant challenge to blood transfusion safety, as it occurs in HBsAg-negative blood donors who are anti-HBc positive and carry detectable hepatitis B virus (HBV) DNA. The lack of additional serological screening and accessible molecular testing in blood banks allows blood units with anti-HBc positivity and HBV DNA to be transfused. The aim of the study was to determine the residual transfusion risk and to identify OBI genotypes among blood donors at the Yaoundé Central Hospital.

methodsThis cross-sectional, analytical, and descriptive study involved 269 blood donors between February and June 2025 at the Yaoundé Central Hospital blood bank and at the Centre Pasteur du Cameroun. Informed consent was obtained from all participants. HBsAg was screened through both Rapid Diagnostics Test (RDTs) and Enzyme Linked Immunosorbent Assay (ELISA). ELISA was used for the detection of Anti-HBc IgM and IgG antibodies. Testing for occult HBV infection in the HBsAg-negative, anti-HBc-positive subjects was performed using quantitative polymerase chain reaction (qPCR). HBV genotypes were determined by sequencing a fragment of the surface gene (PreS1) and then performing phylogenetic analysis of the nucleotide sequences. Statistical analysis was performed using R software 4.4.3.

resultsOf the 269 donors, 168 (62.45%) were HBsAg-negative and anti-HBc-positive. HBV DNA was detected in 9 donors, confirming occult HBV infection with a residual transfusion risk of 3.34%. The number of prior donations was significantly factor negatively associated with HBV DNA presence (p = 0.021, OR [95% CI]: 0.13 [0.0-0.80]). Sequencing of the PreS1 gene fragment from 3 isolates revealed co-circulation of HBV genotypes A and E in the studied population.

conclusionThis study highlights that only sensitive HBV DNA screening would improve blood safety since anti-HBc screening would exclude 60% of donors in a situation of blood shortage. However, the cost of such testing, even in the low yield pools of 6 as practice in some countries, is likely prohibitive in Cameroon. In present Cameroon situation, systematic, compulsory, vaccination would be the best affordable prevention of OBI transfusion transmission.

trial registrationThe study protocol was reviewed and approved by the Regional Ethics Committee for Human Health Research of the Center (CRERSH/C) (Number 000734/ CRERSHC/2025) and adhered to the ethical guidelines outlined in the 1975 Declaration of Helsinki.