Occult Hepatitis B virus infection in previously screened, blood donors in Ile-Ife, Nigeria: implications for blood transfusion and stem cell transplantation

Abstract

BackgroundHepatitis B virus (HBV) transmission through blood transfusion is reduced by screening for hepatitis B surface antigen (HBsAg). However this method cannot detect the presence of occult hepatitis B virus infection. This study sought to determine the prevalence of occult hepatitis B virus infection among blood donors in Ile-Ife, Nigeria. For the first time in Nigeria we employed an automated real-time PCR- method to investigate the prevalence of occult HBV in blood donors.MethodsBlood donors screened with HBsAg immunochromatographic rapid test kits at the blood transfusion units of two hospitals and found to be negative were recruited into the study. Questionnaires to elicit risk factors for HBV infection were administered and then 10 ml of blood was collected from each donor. Plasma samples obtained from these HBsAg negative blood donors were screened again for HBsAg using an enzyme-linked immunosorbent assay (ELISA) method, and those found negative were screened for the presence of total antibody to the HBV core antigen (anti-HBc) using ELISA method. Those positive to anti-HBc were then tested for HBV DNA, using an automated real-time PCR method.ResultsFive hundred and seven blood donors found HBsAg negative by immunochromatographic rapid test kits at both blood transfusion units, were tested for HBsAg using ELISA and 5 (1 %) were HBsAg positive. The 502 found negative were tested for anti-HBc and 354 (70.5 %) were found positive implying previous exposure to HBV and 19 (5.4 %) of the 354 anti-HBc positive had HBV DNA signifying occult HBV infection. No risk factors were found to be associated with the presence of HBV DNA among those who tested positive.ConclusionOccult HBV infection exists in blood donors in Ile-Ife, Nigeria and the use of HBsAg alone for screening prospective donors will not eliminate the risk of HBV transmission in blood transfusion or stem cell transplantation.

Occult Hepatitis Infection in Transfusion Medicine: Screening Policy and Assessment of Current Use of Anti-HBc Testing

“…In recent years, several studies on the infectivity of OBI donors via blood transfusion were reported [10][11][12][13][14]. In Italy, two cases of posttransfusion hepatitis were found in which the sequence identity of donor-recipient by phylogenetic analysis was confirmed [16].…”

“…Nevertheless, HBV continues to be the most common posttransfusion infection because the residual risk is not limited to pre-seroconversion window period, but it extends to donors with OBI [6,[10][11][12][13][14]. These donors do not exhibit significant levels of HBs-Ag in the serum, with fluctuating low levels of viremia.…”

“…It is necessary to maintain a high level of attention for identifying OBI carriers, especially in blood banks [10][11][12][13][14]. For this reason, it is necessary to use advanced testing to detect both common and uncommon HBV genotypes as well as escape mutants ( fig.…”

“…Several studies reported HBV transmission through blood components from asymptomatic apparently healthy individuals such as blood donors that were later revealed as affected by occult HBV infection (OBI) [10][11][12][13][14].…”

Characterization of hepatitis B virus (HBV) preS/S gene mutations in blood donors with occult HBV infection in the Baoji area of North China

“…Among blood donors in recent years, the incidence of OBI has varied with the prevalence of HBV and public health conditions. Specifically, the OBI incidence was 1:27 (19 of 507 donors) in Nigeria, 1:450 (8 of 3600 donors) in the Brazilian Amazon, 1:2450 (163 of 399,326 donors) and 1:3239 (95 of 307,740 donors) at the Hong Kong Red Cross Blood Transfusion Service and Shenzhen Blood Center of South China, 1:19,130 (23 to 4.4 million donors) in the Netherlands, 1:14,903 (34 of 506,689 donors) in Spain, at least 1:2200 (548 of 1,205,796 donors) in a multicenter investigation in China, and 1:5045 (298 of 1,503,484 donors) in a worldwide, multicenter investigation . A recent survey conducted by the National Institute of Diagnostics and Vaccine Development in Infectious Diseases of China showed that the incidence of OBI in blood donors in South China was 1:631 (61 of 38,499 donors), and more than one‐half (34 of 61 donors) of the OBI blood samples harbored major hydrophilic region (MHR) mutations, which are associated with failure to detect HBsAg .…”