Transfusion-transmitted Hepatitis B Virus Research Articles

Incidence of Occult Hepatitis B Infection (OBI) and hepatitis B genotype characterization among blood donors in Cameroon.

Occult hepatitis B infection (OBI) is characterized by the presence of hepatitis B virus (HBV) DNA at low levels in serum (<200 IU/mL) with a negative hepatitis B surface antigen (HBsAg) test. OBI remains a major challenge to blood safety, particularly in HBV-endemic regions like Cameroon, where HBV detection relies solely on HBsAg testing. This cross-sectional study aimed to investigate the actual incidence and genotype characteristics of OBI in Cameroonian blood donors. Between March and June 2023, samples were collected from 288 HBsAg-negative blood donors aged 18 to 55 years and analysed for antibodies against the HBV core (anti-HBc) and surface antigens (anti-HBs). Following DNA extraction from the serum samples, qualitative nested PCR and quantitative real-time PCR were used to detect HBV viral DNA and viral load respectively. For positive samples, sequencing of a fragment of the S gene was performed to identify the circulating HBV genotypes. The findings revealed that 58% (n = 167/288) of blood donors tested positive for anti-HBc, 29% (n = 83/288) tested positive for anti-HBs, and 26% (n = 75/288) being positive for both anti-HBc and anti-HBs. Occult hepatitis was confirmed in 4.5% of the blood donors, all of whom belonged to either HBV genotypes A or E, which are predominant in Cameroon. The amino acid substitution sA184V associated with HBsAg detection failure in genotype E was observed in 70% of OBI sequences, and the HBsAg immune escape variants (sT131N and sS143L) implicated in OBI were also observed. The mutation rtN139K in the reverse transcriptase (RT) domain of the overlapping HBV polymerase (P) gene was present in 17% of OBI-positive sequences of genotype E, likely contributing to masking HBsAg secretion. The results suggest a considerable risk of transfusion-transmitted HBV in this region. Therefore, to ensure blood safety, nucleic acid testing (NAT) is recommended, as relying solely on HBsAg assays is insufficient to eliminate this risk.

Cost-benefit analysis of serological and nucleic acid testing for hepatitis B virus in blood donors in southern China

BackgroundMost Chinese blood centers have implemented mini pool (MP) HBV nucleic acid testing (NAT) together with HBsAg ELISA in routine blood donor screening for HBV infection since 2015, and a few centers upgraded MP to individual donation (ID) NAT screening recently, raising urgent need for cost-benefit analysis of different screening strategies. In an effort to prevent transfusion-transmitted infections (TTIs) for HBV, cost-benefit analyses of three different screening strategies: HBsAg alone, HBsAg plus MP NAT and HBsAg plus ID NAT were performed in blood donors from southern China where HBV infection was endemic.MethodsMP-6 HBV NAT and ID NAT were adopted in parallel to screen blood donors for further comparative analysis. On the basis of screening data and the documented parameters, the number of window period (WP) infection, HBV acute infection, chronic hepatitis B infection (CHB) and occult hepatitis B infection (OBI) was evaluated, and the potential prevented HBV TTIs and benefits of these three strategies were predicted based on cost-benefit analysis by an estimation model.ResultsOf 132,323 donations, the yield rate for HBsAg-/DNA + screened by ID NAT (0.12%) was significantly higher than that by MP NAT (0.058%, P < 0.05). Furthermore, the predicted transfusion-transmitted HBV cases prevented was 1.25 times more by ID NAT compared to MP-6 NAT. The cost-benefit ratio of the universal HBsAg screening, HBsAg plus ID NAT and HBsAg plus MP NAT were 1:58, 1:27 and 1:22, respectively.ConclusionsUniversal HBsAg ELISA screening in combination with HBV ID NAT or MP-6 NAT strategies was highly cost effective in China. To further improve blood safety, HBsAg plus HBV DNA ID NAT screening should be considered in HBV endemic regions/countries.

Molecular genetic characterization of hepatitis B virus in blood donors from South Vietnam

The problem of transfusion safety preventing parenteral viral hepatitis transmission remains relevant. Viral hepatitis B (HB) is the most common viral infection transmitted through transfusion procedures. One of the natural phases of a chronic viral hepatitis B (CHB) course is occult hepatitis B infection (OBI) characterized by undetectable HBsAg level (regardless of other serological marker levels) along with detected hepatic HBV DNA as well as blood viral load ranging from extremely low to undetectable. In Vietnam, prevention of transfusion-based HBV transmission is focused on donor screening; it is still based solely on HBsAg serology. As such, OBI remains a potential threat to blood transfusion safety. Assessing hepatitis B virus (HBV) DNA is a reliable preventive measure against HBV transmission from HBsAg– donors, especially in highly endemic regions. The aim of our work was HBV identification and molecular genetic characterization in blood donors from South Vietnam. The study material was presented by 500 donor serum samples. Subjects were examined for HBV markers with qualitative detection of HBsAg, HBs IgG, and HBcore IgG. Amplification and subsequent HBV sequencing were performed using nested PCR with overlapping primer pairs jointly flanking the complete HBV genome (S, P, C, X genes). Full-size HBV genome nucleotide sequences were obtained for 58 samples. Among blood donors, taking into account HBsAg+ and HBsAg– samples, HBV DNA was detected in 11.6%, including 8.6% OBI. HBV phylogenetic analysis showed genotypes B and C. Vaccine escape mutations and mutations that contribute to disease progression were identified. Current screening in Vietnam is insufficient for eliminating the risk of transfusion-transmitted HBV infection. The major risk factor is OBI. PCR testing for HBV should be considered for blood donor screening.

Blood donation screening for hepatitis B virus core antibodies: The importance of confirmatory testing and initial implication for rare blood donor groups.

Exclusion of blood donors with hepatitis B virus (HBV) core antibodies (anti-HBc) prevents transfusion-transmitted HBV infection but can lead to significant donor loss. As isolated anti-HBc positivity does not always indicate true past HBV infection, we have investigated the effectiveness of confirmatory anti-HBc testing and the representation of rare blood groups in anti-HBc-positive donors. Three hundred ninety-seven HBV surface antigen-negative and anti-HBc initially reactive blood donor samples were tested by five different anti-HBc assays. Eighty percentage of samples reactive in Architect anti-HBc assay were positive by the Murex assay and anti-HBc neutralization. Eleven out of 397 samples showed discordant results in supplementary testing from the Murex confirmatory test result, and five remained undetermined following extensive serological testing. Thirty-eight percentage of anti-HBc-positive donors identified as minority ethnic groups compared with 11% representation in anti-HBc-negative donors (p < 0.0001); the frequency of the Ro blood group in anti-HBc-positive donors was 18 times higher in non-white ethnic groups. Using two anti-HBc assays effectively enabled the identification of HBV-exposed and potentially infectious donors, their deferral and potential clinical follow-up. However, the exclusion of confirmed anti-HBc-positive donors will still impact the supply of rare blood such as Ro.

Biomarkers of transfusion transmitted occult hepatitis Bvirus infection: Where are we and what next?

Blood transfusion is a vital procedure, where transfusion-transmitted infection of hepatitis B virus (HBV) remains an important issue, especially from blood donors with occult hepatitis B virus infection (OBI). Occult hepatitis B virus infection is a complex entity to detect using surrogate blood biomarkers for intrahepatic viral transcriptional activity, requiring a continually refined battery of tests utilised for screening. This review aims to critically evaluate the latest advances in the current blood biomarkers to guide the identification of OBI donors and discuss novel HBV markers that could be introduced in future diagnostic practice. Challenges in detecting low HBV surface antigen levels, mutants, and complexes necessitate ultrasensitive multivalent dissociation assays, whilst HBV DNA testing requires improved sensitivity but worsens inaccessibility. Anti-core antibody assays defer almost all potentially infectious donations but have low specificity, and titres of anti-surface antibodies that prevent infectivity are poorly defined with suboptimal sensitivity. The challenges associated with these traditional blood HBV markers create an urgent need for alternative biomarkers that would help us better understand the OBI. Emerging viral biomarkers, such as pre-genomic RNA and HBV core-related antigen, immunological HBV biomarkers of T-cell reactivity and cytokine levels, and host biomarkers of microRNA and human leucocyte antigen molecules, present potential advances to gauge intrahepatic activity more accurately. Further studies on these markers may uncover an optimal diagnostic algorithm for OBI using quantification of various novel and traditional blood HBV markers. Addressing critical knowledge gaps identified in this review would decrease the residual risk of transfusion-transmitted HBV infection without compromising the sustainability of blood supplies.

Prevalence and Trends of Transfusion-Transmissible HBV Infection Among Blood Donors in Southwestern China: A Six-Year Retrospective Study.

Hepatitis B virus (HBV) infection is a significant global public health concern, with variable prevalence rates across regions. The prevalence of transfusion-transmitted HBV infection (TT-HBV) via donated blood necessitates an evaluation of blood safety and potential risks to the population. This study assessed the prevalence of HBV infection among blood donors in Southwestern China over 6 years. We analyzed 903,023 blood donations from a central blood center in Southwestern China between January 2017 and December 2022. The prevalence of HBV in donations was determined for one-time and repeat donors, considering birth cohorts and covariates. Demographic characteristics, donation frequency, and anti-HBV antibody status were analyzed to estimate the incidence of TT-HBV. One-time donors provided 47.78% of the samples, and 52.22% were from repeat donors. The HBV prevalence decreased from 1.0% in 2017 to 0.87% in 2022 in one-time donors and from 0.30% to 0.09%, respectively, in repeat donors. A significantly lower HBV prevalence was identified in the post-1992 birth cohort (0.33%) than in the pre-1992 birth cohort (1.67%). The estimated incidences of TT-HBV occurring from one-time donors, repeat donors, post-1992 birth cohort donors, and pre-1992 birth cohort donors were 20.76, 13.84, 0.82, and 20.98 per 104 person-years, respectively. Our findings indicate a decreasing trend in HBV prevalence among blood donors in Southwestern China over the 6-year study period. This decline may be attributed to the widespread administration of HBV vaccinations and stringent screening measures implemented by blood donation centers. Continuous monitoring for HBV among blood donors is necessary to evaluate the effectiveness of preventive measures and inform future strategies to reduce transmission.

Marked reduction in the incidence of transfusion-transmitted hepatitis B virus infection after the introduction of antibody to hepatitis B core antigen and individual donation nucleic acid amplification screening in Japan.

In Japan, 41 million blood donations have been screened for hepatitis B virus (HBV) during the past 8.4 years using individual donation nucleic acid amplification testing (ID-NAT) and antibody to hepatitis B core antigen (anti-HBc) screening. Transfusion-transmitted HBV infection (TT-HBV) incidence was examined. Donated blood implicated in TT-HBV was analyzed for infection stage and DNA levels. Causative HBV strains were phylogenetically analyzed. Among 5162 (0.013%) ID-NAT positives, window period (WP) and occult HBV infection (OBI) accounted for 3.4% (176) and 11.5% (594), respectively. No OBI-related TT-HBV occurred. Seven blood donations caused eight TT-HBV cases, six of which were in the pre-ID-NAT WP, leaving one with an unresolved infection stage. Seven cases were caused by platelet concentrate (180 mL plasma) and one case by fresh-frozen plasma (200 mL plasma), which contained estimated infectious doses varying between 2 and 2300 HBV virions. HBV subgenotypes in five cases were HBV/A2. Complete genome sequences of the transmitting A2 strains were nearly identical (99.6%-100%) and clustered in a group that included HBV/HIV-1 coinfections and a higher proportion of donors in the acute infection phase (69%) than the other group of HBV/A2 sequences (5%). The incidence of observed TT-HBV cases has significantly reduced to 0.19 per million in the ID-NAT screening period. OBI-related TT-HBV was eliminated by anti-HBc screening. Established TT-HBV cases were caused by blood products with large plasma volumes containing extremely low HBV concentrations derived from blood donors at a very early infection stage.

Insights on 21 Years of HBV Surveillance in Blood Donors in France.

Hepatitis B virus (HBV) infection is the most frequent viral infection found in blood donors (BDs) in France. We analyzed the epidemiological and sero-molecular data on HBV infection gathered over the past two decades by the French haemovigilance surveillance network, blood screening laboratories, and the national reference center for transfusion infectious risks (NRC). Between 2000 and 2020, 6149 of the 58,160,984 donations (1.06/10,000) tested HBV positive, 98% of them from first-time blood donors (FTBDs). In addition, 2212 (0.0071%) of the 30,977,753 donations screened for HBV DNA tested DNA positive, of which 25 (1.1%) were positive only for this marker. HBV prevalence decreased by 2.8-fold and the residual risk for transfusion-transmitted HBV infection decreased 13-fold and was divided by 13. The major risk factor for HBV infection was the origin of donors (endemic country, 66.5%), followed by parenteral exposure (10.7%). In the whole HBV-positive BD population, genotype D was predominant (41.8%), followed by genotypes A (26.2%) and E (20.4%), reflecting the geographical origin of donors. The low and decreasing prevalence and incidence of HBV infection in French BDs, coupled with a screening strategy using three HBV markers (HBsAg, anti-HBc and DNA), ensures a high level of blood safety, further reinforced by the implementation of pathogen-reduction measures.

Characteristic of HBV nucleic acid amplification testing yields from blood donors in China

BackgroundNucleic acid amplification testing (NAT) for blood screening has been previously performed in some countries to determine NAT yields. The current study sought to explore the non-discriminating reactive NAT yields using individual-NAT (ID-NAT) and characteristics of HBV NAT yields through a 10-year retrospective analysis in Zhejiang, China.MethodsBlood donations were analyzed using individual-NAT mode by the transcription-mediated amplification (TMA) method. Supplementary HBV serological tests were performed using chemiluminescent immunoassay, and HBV viral load assay was performed by real-time polymerase chain reaction. Follow-up studies were performed in partial donors with low HBV viral loads.ResultsNon-discriminating reactive NAT yields and HBV NAT yields varied in different years. The yields ranged from 853.73 per million to 2018.68 per million and 624.60 per million to 1669.50 per million, respectively. In the 476 NAT yields, 19 were probable window periods (WP), 33 probable occult hepatitis B virus infections (OBIs), 409 were confirmed OBIs and 15 were chronic HBV infections. ID-NAT results were categorized in four groups, and the findings showed that the levels of HBV DNA viral loads were different in the four different groups (χ2 = 275.02, p < 0.01). HBV viral load distribution was significantly different between anti-HBs positive and anti-HBc positive samples (χ2 = 49.429, p < 0.01). Notably, only 42.03% donors were NAT repeated positive in the 138 repeat donors’ follow up tests.ConclusionNAT screening of blood donations can reduce the risk of transfusion-transmitted HBV infections. Positive proportions of anti-HBs and anti-HBc are correlated with the HBV viral load level. However, low level of viral load donors pose risks in HBV NAT assays, and show fluctuating state for HBV viral load and leads to non-repeated NAT results during follow up studies.

An assessment of hepatitis B virus prevalence in South African young blood donors born after the implementation of the infant hepatitis B virus immunization program: Implications for transfusion safety.

The prevalence of hepatitis B surface antigen is estimated to be 6.7% in the South African population and in April 1995 the nation introduced universal hepatitis B virus (HBV) vaccination for newborns and infants. We studied the temporal association of this program with HBV prevalence in young blood donors and the contemporary HBV incidence and residual risk of transfusion-transmitted HBV infection (TT-HBV). We used blood donation data from January 2011 to December 2019. Estimation of HBV prevalence donations made by first-time blood donors were analyzed by birth cohort and covariates. To estimate the incidence and residual risk of TT-HBV, mathematical models used data from both first time and repeat donors. HBV prevalence in first-time donors decreased from 0.84% (95% confidence interval [CI] 0.78-0.90) in 2011 to 0.66% (95% CI 0.61-0.70) in 2019. The post-1995 birth cohort had a significantly lower HBV prevalence of 0.14% (95% CI 0.13-0.15) than the pre-1985 birth cohort of 1.29% (95% CI 1.25-1.33) and the odds of HBV infection were reduced in a multivariable model (odds ratio [OR]=0.28, 95% CI 0.24-0.34). The residual risk of TT-HBV occurring from window-period, occult, and possible vaccine breakthrough infections were estimated at 36.9, 5.8, and 2.2 per million red blood cell transfusions, respectively. Donors born after the start of routine HBV immunization had significantly lower prevalence of HBV infection, supporting the effectiveness of the vaccination program. The contemporary residual risk of TT-HBV has decreased and should decline further as more vaccinated young people join the donor pool.

Role of core protein mutations in the development of occult HBV infection

Occult HBV infection (OBI) is associated with transfusion-transmitted HBV infection and hepatocellular carcinoma. Studies on OBI genesis have concentrated on mutations in the S region and the regulatory elements. Herein, we aimed to determine the role of mutations in the core region on OBIs. An OBI strain (SZA) carrying 9 amino acid (aa) substitutions in the core protein/capsid (Cp) was selected by sequence alignment and Western blot analysis from 26 genotype B OBI samples to extensively explore the impact of Cp mutations on viral antigen production invitro and invivo. A large panel of 30 Cp replicons were generated by a replication-competent pHBV1.3 carrying SZA or wild-type (WT) Cp in a 1.3-fold over-length of HBV genome, in which the various Cp mutants were individually introduced by repairing site mutations of SZA-Cp or creating site mutations of WT-Cp by site-directed mutagenesis. The expression of HBcAg, HBeAg, and HBsAg and viral RNA was quantified from individual SZA and WT Cp mutant replicons in transfected Huh7 cells or infected mice, respectively. An analysis of the effect of Cp mutants on intracellular or extracellular viral protein production indicated that the W62R mutation in Cp had a critical impact on the reduction of HBcAg and HBeAg production during HBV replication, whereas P50H and/or S74G mutations played a limited role in influencing viral protein production invivo. W62R and its combination mutations in HBV Cp might massively affect HBcAg and HBeAg production during viral replication, which, in turn, might contribute to the occurrence of OBI. Occult hepatitis B virus infections (OBIs) have been found to be associated with amino acid mutations in the S region of the HBV, but the role of mutations in the core protein (Cp) remains unclear. In this study, an OBI strain (SZA) carrying 9 amino acid substitutions in Cp has been examined comprehensively invitro and invivo. The W62R mutation in Cp majorly reduces HBcAg and HBeAg production during HBV replication, potentially contributing to the occurrence of OBI.

Hepatitis B seroprevalence in the U.S. military and its impact on potential screening strategies.

IntroductionKnowledge of the contemporary epidemiology of hepatitis B virus (HBV) infection among military personnel can inform potential Department of Defense (DoD) screening policy and infection and disease control strategies.Materials and MethodsHBV infection status at accession and following deployment was determined by evaluating reposed serum from 10,000 service members recently deployed to combat operations in Iraq and Afghanistan in the period from 2007 to 2010. A cost model was developed from the perspective of the Department of Defense for a program to integrate HBV infection screening of applicants for military service into the existing screening program of screening new accessions for vaccine-preventable infections.ResultsThe prevalence of chronic HBV infection at accession was 2.3/1,000 (95% CI: 1.4, 3.2); most cases (16/21, 76%) identified after deployment were present at accession. There were 110 military service-related HBV infections identified. Screening accessions who are identified as HBV susceptible with HBV surface antigen followed by HBV surface antigen neutralization for confirmation offered no cost advantage over not screening and resulted in a net annual increase in cost of $5.78 million. However, screening would exclude as many as 514 HBV cases each year from accession.ConclusionsScreening for HBV infection at service entry would potentially reduce chronic HBV infection in the force, decrease the threat of transfusion-transmitted HBV infection in the battlefield blood supply, and lead to earlier diagnosis and linkage to care; however, applicant screening is not cost saving. Service-related incident infections indicate a durable threat, the need for improved laboratory-based surveillance tools, and mandate review of immunization policy and practice.

Optimal titer of anti-HBs in blood components derived from donors with anti-HBc.

The ultimate strategy to cope with transfusion-transmitted hepatitis B virus (HBV) infection caused by transfusion of blood from donors with historical HBV infection is to reject all donors having anti-HBV core antigen (anti-HBc). However, this strategy would result in a huge loss of blood donors and subsequent blood inventory collapse. On the other hand, anti-HBc-positive blood is reportedly not infectious when containing more than 100 mIU/mL of anti-HBV surface antigen (anti-HBs). In Japan, anti-HBc-positive blood has been used for transfusion if it contained 200 mIU/mL or more of anti-HBs. First, to verify the screening policy, clinical outcomes for transfusion of such blood were analyzed for the 2008-2012 period. Second, human hepatocyte-repopulated severe combined immunodeficiency mice were inoculated with HBV preincubated with varying doses of anti-HBs, then viremic status was followed. The effects of anti-HBs across different HBV genotypes were also investigated. Twenty-three transfusion-transmitted HBV infections related to anti-HBc-positive blood components were identified. None of the blood responsible for these cases contained 200 mIU/mL or more of anti-HBs. When 100 μL of plasma containing 104 copies of HBV and 20 mIU of anti-HBs was injected into severe combined immunodeficiency mice, no viremia was detected within 13 weeks. Genotype C anti-HBs was capable of total inhibition of genotype A HBV replication, whereas genotype A anti-HBs inhibited genotype C HBV to a lesser extent. Anti-HBc-positive blood containing 200 mIU/mL or more of anti-HBs appears safe as a transfusion component. HBV vaccination seems effective between HBV genotypes A and C.

Prevalence, incidence and residual risk of transfusion-transmitted HBV infection before and after the implementation of HBV-NAT in northern Brazil.

BackgroundNucleic acid testing (NAT) for virus detection during blood screening has helped to prevent transfusion-transmitted infections worldwide. In northern Brazil, NAT was implemented in 2012 for HIV and HCV and more recently, in January 2015, the screening for HBV was included and currently used concomitant with serological tests (HBsAg and anti-HBc). This study aims to evaluate the prevalence and the incidence of HBV infection among voluntary blood donors at ten regional blood centers of HEMOPA Foundation in Pará state and to compare the residual risk of transfusion-transmitted HBV infection before and after the Brazilian HBV-NAT implementation.MethodsThe prevalence (restricted to first time donors- FT) and seroconversion rate (restricted to repeat donors- RP) of HBV were calculated based on rates of confirmed positive samples. Residual risk was based on the incidence and window period (WP) model described by Schreiber and coauthors. Logistic and Poisson regression were used in the statistical analysis by SPSS v20.0. A p value <0.05 was considered statistically significant.ResultsHBV prevalence in the periods before and after the implementation of HBV-NAT were 247 and 251 per 100,000 donations, respectively. Seroconversion rates were 114 and 122 per 100,000 donations in the two periods, respectively. The residual risk (RR) for HBV decreased significantly in the posterior period to the HBV-NAT implementation, when compared to RR before implementation, with a reduction of 1:144,92 to 1:294,11 donations (p <0,001).ConclusionsThe RR to HBV decreased after the implementation of HBV-NAT, increasing significantly the transfusional security in the North region of Brazil at HEMOPA Foundation.

Significance of HBV NAT Among HBs Antigen-Negative Blood Donors in Saudi Arabia.

Bloodborne hepatitis B virus (HBV) transmission from asymptomatic donors with acute HBV infections who have undetectable surface antigen of HBV (HBsAg), or from donors with chronic infections in whom serological markers were not detected, could cause residual infections leading to relevant transfusion-transmitted infections (RTTIs). HBV nucleic acid testing (NAT) can detect HBV DNA in the HBsAg-negative and total hepatitis B core antibody (anti-HBc)-negative window period of infection and in chronic cases. To assess the presence or absence of HBV DNA in blood donors with HBsAg negativity. We collected 3014 blood specimens from volunteer blood donors at the blood bank of King Khalid University Hospital in Riyadh, Saudia Arabia. Specimens from each donor were tested for HBsAg, anti-HBc, and hepatitis B surface antibody (anti-HBs) by commercial immunoassays and for qualitative assessments of HBV-DNA by HBV-NAT testing. Of the 3014 donors, 7 (0.23%) tested positive for HBsAg and anti-HBc, 1 for HBsAg (0.03%) only, and of those 264 donors (8.8%) for anti-HBc. Of these last, 6.9% also tested positive for anti-HBs and 1.9% tested negative for anti-HBs. HBV-NAT testing was reactive in 75.0% of subjects who tested HBsAg positive, and nonreactive in 100% of subjects who tested anti-HBc positive/HBsAg negative (with or without anti-HBs). Among 2742 donors who tested seronegative, 1 specimen was determined to be reactive via HBV-NAT testing. The frequency of HBV DNA in blood donors who tested seronegative was low. This finding may indicate the significance of the HBV NAT technique in reducing the residual risk of transfusion-transmitted HBV infection.

The current incidence, prevalence, and residual risk of hepatitis B viral infections among voluntary blood donors in China

BackgroundThere are few data available on the prevalence, incidence, and residual risk of transfusion-transmitted HBV (TT-HBV) infections among Chinese blood donors. This study investigated the demographic characteristics of blood donors, as well as the prevalence, incidence, and residual risk (RR) of TT-HBV infections in six large blood centers in different regions of China.MethodsThe demographic characteristics and HBV screening test results of blood donors from six blood centers in different regions in China were collected and analyzed. The hepatitis B surface antigen (HBsAg) yield approach was used to estimate the incidence of HBV. Then, the RR of TT-HBV infections was evaluated using the incidence-window period model.ResultsThe majority of donors were between 18 and 35 years old (including 35), with the exception of the Changzhi Blood Center where a majority of donors were between 35 and 55 years old (including 55). The prevalences of HBV were 0.13%, 0.078%, 0.16%, 0.07%, 0.20%, 0.25% in Hefei, Dalian, Changzhi, Kaifeng, Mianyang and Fujian, respectively. The estimated corresponding incidences were 213.44, 161.59, 989.80, 278.05, 125.31 and 352.19 per 105 person-years. Using an infectious window period of 59 days, the RR for HBV was estimated to be 34.14, 25.85, 158.35, 44.48, 20.04 and 56.35 per 105 person-years in Hefei, Dalian, Changzhi, Kaifeng, Mianyang and Fujian, respectively.ConclusionDespite the introduction of more sensitive assays in blood screening, our data revealed that the current residual risk of TT-HBV infection was still high (overall 56.53 per 105 py). A continuous monitoring of the residual risk of transfusion-transmitted infections is crucial for safe blood management.

PURSUING EPIDEMIOLOGICAL INVESTIGATION OF CASES OF POSSIBLE HBV OR HCV INFECTION OF THE RECIPIENT WITH TRANSFUSIONS OF DONOR BLOOD COMPONENTS

Background. Nosocomial transmission of HBV and HCV is often believed to be associated with transfusion of inapparent infection blood. Nevertheless, recently both promotion of voluntary (fee free) donorship and the evolution of laboratory screening, including the introduction of high-sensitivity tests, have significantly reduced the transfusion-associated complications, including infectious ones. The incidence ratae of primary transfusion-transmitted infections in patients with hematological malignancies remains to be high. A lot of publications are devoted to epidemiological studies on the determination of the source of infection with parenteral viral hepatitis by virtue of molecular analysis of viral strains, which is one of the important tools for obtaining objective data on the presence or absence of epidemiological relationship in the investigation of iatrogenic cases of infection. However, there is still no clear algorithm for pursuing epidemiological investigations of such cases. The aim of this study was to develop the procedure for the epidemiological investigation of probable transfusion-transmitted HBV and HCV infection with the use of Laboratory Information System and Transfusiology Information System software in patients with hematological malignancies. Material and methods. 6 cases of primary HBV and 3 cases of primary HCV were registered in patients with hematological malignancies in the National Medical Research Center for Hematology. All patients had a history of blood transfusions. A two-steps procedure for the epidemiological investigation was developed. 5 epidemiological investigations were held according to this procedure. 35 archival blood samples (7 from patients and 28 from blood donors) were tested for serological and/or molecular markers of HBV and HCV to fulfill this. Results. First step of procedure includes the determination of the date of initial infection (IID). IID is an earliest point of maximal likelihood of the detection of viral markers by laboratory techniques. This value is calculated on the basis of the results of a comprehensive virological examination of the recipient. The second step includes a history of blood transfusions from IID up to date of initial detection of primary infection evaluation. Then the analysis of donor-recipient pairs should be executed for the detection of probable sources of infection. As the result of study 5 epidemiological investigations were held in accordance to the developed procedure and the Laboratory Information System and Transfusiology Information System software. Two of the five investigations cannot be completed because of donors’ rejection to undergo a follow-up examination. In other cases infection transmission through the blood transfusion was excluded. Conclusion. A standard operating procedure of epidemiological investigation of HBV or HCV transmission has been developed and implemented. In order to reveal the latent forms of these infections a protocol of viral screening in patients with hematological malignancies at the admission to hematology ward was also developed and implemented.

Value of retaining HBsAg donor screening where HBV NAT and anti‐HBc donor screening apply

Hepatitis B virus (HBV) is a transfusion‐transmissible human DNA virus with a global distribution. Since the early 1970s, hepatitis B surface antigen (HBsAg) detection has been the mainstay to identify donors infected with HBV. The implementation of donor HBsAg screening substantially reduced but did not eliminate the risk of transfusion‐transmitted HBV (TT‐HBV). In the late 1970s, it was recognized that TT‐HBV occurred more commonly from HBsAg‐negative donations containing detectable antibodies to the viral core (anti‐HBc) leading to some countries subsequently implementing universal anti‐HBc screening in addition to HBsAg.Since the late 1990s, HBV nucleic acid tests (NATs) have been applied to donation screening to ‘close’ the acute window period, thereby reducing the residual risk of TT‐HBV. Their implementation also identified HBsAg‐negative/anti‐HBc‐positive individuals with detectable HBV DNA, a novel pattern of infection termed occult hepatitis B infection. A number of countries now combine HBsAg, anti‐HBc and HBV NAT donation testing, which provides the opportunity to determine the proportional HBV risk reduction contribution of each test. The cumulative published data indicate HBV‐infected donors with HBsAg as the only marker are exceedingly rare, occurring at a rate of about 1 in 4 million in the largest published study. There are no recorded cases of TT‐HBV involving ‘HBsAg‐only’ positive donors.Ultimately, HBsAg testing retains value for characterizing the HBV infection stage, but the accumulating data strongly suggest that HBsAg testing now adds little, if any, TT‐HBV risk reduction value where sensitive HBV NAT and anti‐HBc screening also apply.

A 30-year systematic review and meta-analysis of hepatitisB virus among blood donors in mainland China: revealing increase of new threats.

Although screening strategies have been routinely implemented in blood centers, the residual risk of transfusion-transmitted hepatitisB virus (HBV) still poses a public health concern in China. The aim of this study is to investigate the HBV blood screening reactive rate and to illustrate the demographics of the corresponding blood donors with revealing of heterogeneity between previous studies and discovering potentially negligent threats. Literature reporting the HBV screening reactive rate in Chinese blood donors was identified by systematic searching of four electronic databases. We followed the Preferred Reporting of Items for Systematic Reviews and Meta-Analyses guidelines, and data manipulation and statistical analyses were performed by Stata 12.0. Our results showed that the pooled postdonation screening reactive rate was 1.32% (95% confidence interval [CI], 1.28%-1.36%) with a significant variation from 3.93% (95% CI, 3.45%-4.40%) before 1998 to 1.22% (95% CI, 1.18%-1.27%) after 1998 when the Blood Donation Law was implemented. Importantly, the HBV screening reactive rates were significantly higher among replacement and planned donors than among individual voluntary donors. Our results indicated blood centers in China should recruit more individual and group voluntary donors and convert more eligible first-time donors into repeat donors to reduce the risk of transfusion-transmitted HBV.

The characteristics of hepatitisB surface antigen (HBsAg)-negative hepatitisB virus (HBV) infection in Chinese blood donors: a follow-up study of donors tested negative for HBsAg and reactive for simultaneous nucleic acid testing of HBV, hepatitisC virus, and human immunodeficiency virus.

The real infection status of hepatitis B virus (HBV) of hepatitisB surface antigen (HBsAg)-negative yet nucleic acid test (NAT)-positive blood donors is difficult to clarify. Detailed follow-up study is needed for analyzing the infectivity of these blood donors. Blood donors who screened negative for HBsAg and reactive for simultaneous NAT of HBV, hepatitisC virus (HCV), and human immunodeficiency virus (HIV) were included in a follow-up epidemiologic questionnaire survey and contributed follow-up samples for further testing. The follow-up samples were tested repeatedly for the serologic markers and HBV DNA. The genotypes and sequence mutations of HBV infected by 11 HBV DNA-positive donors were analyzed through the amplification and sequencing of HBV S region. Of the 46 donors included in this study, 89.1% were infected with HBV (41/46), including one (2.2%) window period infection, three (6.5%) recovered infections, and 37 (80.4%) occult HBV infections (OBIs). The S region of HBV was successfully amplified and sequenced for seven donors, five infected with Genotype B (71.4%), one with Genotype C (14.3%), and one with Genotype D (14.3%). Mutations in the S region were detected in four donors (57.1%) CONCLUSIONS: This is the first detailed study with multiple follow-up testing of the HBV infection status among blood donors who were tested negative for HBsAg and reactive for simultaneous NAT of HBV, HCV, and HIV. Most of these donors were infected with HBV with very low viral load. Our findings indicate that it is important to improve the sensitivity of NAT so as to decrease the residual risk of transfusion-transmitted HBV infection.