Transfusion-transmitted Viruses Research Articles

High Hepatitis E Virus (HEV) Seroprevalence and No Evidence of HEV Viraemia in Vietnamese Blood Donors.

The prevalence of hepatitis E virus (HEV) in the Vietnamese population remains underestimated. The aim of the present study was to investigate the seroprevalence of HEV IgG/IgM antibodies and the presence of HEV RNA in blood donors as a part of epidemiological surveillance for transfusion-transmitted viruses. Serum samples from blood donors (n = 553) were analysed for markers of past (anti-HEV IgG) and recent/ongoing (anti-HEV IgM) HEV infections. In addition, all serum samples were subsequently tested for HEV RNA positivity. The overall prevalence of anti-HEV IgG was 26.8% (n = 148/553), while the seroprevalence of anti-HEV IgM was 0.5% (n = 3/553). Anti-HEV IgG seroprevalence in male and female donors was similar (27.1% and 25.5%, respectively). A higher risk of hepatitis E exposure was observed with increasing age. None of the blood donors were HEV RNA positive, and there was no evidence of HEV viraemia. Although the absence of HEV viraemia in blood donors from Northern Vietnam is encouraging, further epidemiological surveillance in other geographical regions is warranted to rule out transfusion-transmitted HEV.

Monitoring viral genomic sequences in transfusion-transmitted viruses.

Monitoring genomic sequences of blood-borne viruses infecting blood donors enables blood operators to undertake molecular epidemiology, confirm transfusion transmission and assess and characterize molecular and serological screening assays. The purpose of the study was to determine how blood operators globally value viral diversity surveillance and to assess its impact. An electronic questionnaire was developed and circulated to members of the International Society of Blood Transfusion-transmitted infectious diseases working party. Responses were compiled and complete data sets were analysed. Ninety-seven percent of respondents agreed that monitoring viral genomic sequences was important to blood operators and the transfusion community. However, only 47% of respondents are currently doing this monitoring. The main limitations reported were a lack of financial resources and expertise. Sequencing techniques, primarily next-generation sequencing and also Sanger sequencing, were considered most appropriate, with the preferred option for testing being regional or national reference centres. Respondents agreed that engagement with public health authorities needs to be enhanced. Monitoring genomic sequences of blood-borne viruses is widely considered important by the transfusion community because of its direct applications for transfusion safety, and beyond for public health in general. Therefore, there is a need to strengthen collaboration between blood operators and public health authorities. While national and regional reference centres may be the most appropriate structure for such testing, international collaborations should not be overlooked. Overcoming financial barriers will be an important hurdle for many.

Viral Metagenomics for Identification of Emerging Viruses in Transfusion Medicine.

Viral metagenomics has revolutionized our understanding for identification of unknown or poorly characterized viruses. For that reason, metagenomic studies gave been largely applied for virus discovery in a wide variety of clinical samples, including blood specimens. The emerging blood-transmitted virus infections represent important problem for public health, and the emergence of HIV in the 1980s is an example for the vulnerability of Blood Donation systems to such infections. When viral metagenomics is applied to blood samples, it can give a complete overview of the viral nucleic acid abundance, also named "blood virome". Detailed characterization of the blood virome of healthy donors could identify unknown (emerging) viral genomes that might be assumed as hypothetic transfusion threats. However, it is impossible only by application of viral metagenomics to assign that one viral agent could impact blood transfusion. That said, this is a complex issue and will depend on the ability of the infectious agent to cause clinically important infection in blood recipients, the viral stability in blood derivatives and the presence of infectious viruses in blood, making possible its transmission by transfusion. This brief review summarizes information regarding the blood donor virome and some important challenges for use of viral metagenomics in hemotherapy for identification of transfusion-transmitted viruses.

Seronegative human T-cell lymphotropic virus 1 carriers in blood banks: A potential viral source for silent transmission?

Transfusion-transmitted viruses count among the greatest threats to blood safety. In Argentina, current laws oblige testing all donated blood for the presence of antibodies against human T-cell lymphotropic viruses 1 and 2 (HTLV-1/2). In endemic zones of the country, a high rate of seronegative HTLV-1 individuals with clear evidence of infection because of symptoms and/or presence of tax sequences of HTLV-1 and/or IgG anti-Tax antibodies has been recently described. Migration from endemic to nonendemic zones of Argentina is very frequent. During a 1-year period, in the blood bank of Córdoba city, we performed molecular screening of all donors who were born in or arose from endemic zones for HTLV-1/2 in Argentina and neighbouring countries. By screening 219 bp of HTLV-1/2 tax gene, 0.6% (2/317) of the blood donors proved to be positive for HTLV-1 tax sequence. One of the donors presented anti-Tax antibodies, demonstrating the transcriptional activity of the tax gene, and the other donor was also positive for LTR and pol gene sequences. The HTLV-1 genetic analysis of the LTR sequence determined that it belonged to the Cosmopolitan subtype HTLV-1aA. These findings suggest potential limitations of some currently approved screening assays for HTLV-1 detection applied in some donor populations and the possibility of an HTLV-1 seronegative carrier state with the potential for silent transmission by blood.

Deep sequencing applied to the analysis of viromes in patients with beta-thalassemia.

ABSTRACTTo date, blood banks apply routine diagnosis to a specific spectrum of transfusion-transmitted viruses. Even though this measure is considered highly efficient to control their transmission, the threat imposed by emerging viruses is increasing globally, which can impact transfusion safety, especially in the light of the accelerated viral discovery by novel sequencing technologies. One of the most important groups of patients, who may indicate the presence of emerging viruses in the field of blood transfusion, is the group of individuals who receive multiple transfusions due to hereditary hemoglobinopathies. It is possible that they harbor unknown or unsuspected parenterally-transmitted viruses. In order to elucidate this, nucleic acids from 30 patients with beta-thalassemia were analyzed by Illumina next-generation sequencing and bioinformatics analysis. Three major viral families: Anelloviridae, Flaviviridae and Hepadnaviridae were identified. Among them, anelloviruses were the most representative, being detected with high number of reads in all tested samples. Human Pegivirus 1 (HPgV-1, or GBV-C), Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV) were also identified. HBV and HCV detection was expected due to the high seroprevalence in patients with beta thalassemia. Our results do not confirm the presence of emerging or unsuspected viruses threatening the transfusion safety at present, but can be used to actively search for viruses that threaten blood transfusion safety. We believe that the application of viral metagenomics in multiple-transfused patients is highly useful to monitor possible viral transfusion threats and for the annotation of their virome composition.

First Report of Prevalence of Blood-Borne Viruses (HBV, HCV, HIV, HTLV-1 and Parvovirus B19) Among Hemophilia Patients in Afghanistan

Blood-borne viruses including Hepatitis B and C, HIV, HTLV-1 and parvovirus B19 are still a factor of concern, especially for hemophilia patients. Although the safety of the blood supply continues to improve worldwide, the blood supply system in Afghanistan was damaged by many years of conflict and political instability. To date, there are few studies focused on the prevalence of blood-borne viruses in hemophilia patients. This study is first to investigate the prevalence of five blood-borne viruses in Afghanistan hemophilia patients in four cities including Kabul, Herat, Mazar-i-Sharif and Jalal Abad. A total of 80 hemophilia male patients were screening for the presence of five transfusion-transmitted viruses using ELISA and PCR. Data obtained showed 2.5% seropositivity for HBV, 8.75% seropositivity for HCV, and 91.25% seropositivity for parvovirus B19. None of the patients were positive for HIV and HTLV-1 and the prevalence of HCV was higher in older patients rather than younger patients. This finding, the first to report in Afghanistan, shows a high prevalence of parvovirus B19 in Afghanistan hemophilia patients and implementation of highly sensitive screening is necessary.

International survey on the impact of parasitic infections: frequency of transmission and current mitigation strategies.

Globally, blood safety interventions have been successful in mitigating risk of the major transfusion-transmitted (TT) viruses. However, strategies that address risk from parasites are comparatively limited. TT parasites are often regional in nature, posing unique challenges; we sought to understand their impact on blood safety. An electronic questionnaire was distributed to transfusion medicine leaders in 100 countries. The survey focused on specific questions pertaining to four parasitic diseases: babesiosis, Chagas, leishmaniasis and malaria. Respondents provided data on historical TT cases, local epidemiology, policies to mitigate risk and an assessment of public health perceptions for each aetiologic agent. Twenty-eight (28%) surveys were returned from countries in Europe (n=13), the Americas (n=6), Africa (n=4), Asia (n=3) and Oceana (n=2). Historically, no cases of TT leishmaniasis were reported, TT babesiosis was exclusive to Canada and the USA, TT Chagas was limited to the Americas and Spain, while TT malaria was cosmopolitan. Mitigation efforts varied widely; malaria was the most frequently tested parasitic disease. The public's perception of risk for parasitic agents was low, while that of health authorities in endemic countries was higher. The global impact of parasitic infections on blood safety and related mitigation efforts varied widely by parasite epidemiology, test availability, public health priorities and socioeconomic constraints. While parasites continue to pose a risk to blood safety, the successful mitigation of viral risk has elevated the prominence of TT parasites in many locations, thereby requiring consideration of mitigation efforts.

Relative analytical sensitivity of donor nucleic acid amplification technology screening and diagnostic real-time polymerase chain reaction assays for detection of Zika virus RNA.

Zika virus (ZIKV) has spread rapidly in the Pacific and throughout the Americas and is associated with severe congenital and adult neurologic outcomes. Nucleic acid amplification technology (NAT) assays were developed for diagnostic applications and for blood donor screening on high-throughput NAT systems. We distributed blinded panels to compare the analytical performance of blood screening relative to diagnostic NAT assays. A 25-member, coded panel (11 half-log dilutions of a 2013 French Polynesia ZIKV isolate and 2015 Brazilian donor plasma implicated in transfusion transmission, and 3 negative controls) was sent to 11 laboratories that performed 17 assays with 2 to 12 replicates per panel member. Results were analyzed for the percentage reactivity at each dilution and by probit analysis to estimate the 50% and 95% limits of detection (LOD50 and LOD95 , respectively). Donor-screening NAT assays that process approximately 500 µL of plasma into amplification reactions were comparable in sensitivity (LOD50 and LOD95 , 2.5 and 15-18 copies/mL) and were approximately 10-fold to 100-fold more sensitive than research laboratory-developed and diagnostic reverse transcriptase-polymerase chain reaction tests that process from 10 to 30 µL of plasma per amplification. Increasing sample input volume assayed with the Centers for Disease Control and Prevention reverse transcriptase-polymerase chain reaction assays increased the LODs by 10-fold to 30-fold. Blood donor-screening ZIKV NAT assays demonstrate similar excellent sensitivities to assays currently used for screening for transfusion-transmitted viruses and are substantially more sensitive than most other laboratory-developed and diagnostic ZIKV reverse transcriptase-polymerase chain reaction assays. Enhancing sensitivities of laboratory-developed and diagnostic assays may be achievable by increasing sample input.

Optimization of influencing factors of nucleic acid adsorption onto silica-coated magnetic particles: Application to viral nucleic acid extraction from serum

We present a detailed study of nucleic acid adsorption onto silica-coated magnetic particles in the presence of guanidinium thiocyanate, and extraction of nucleic acid from two important transfusion-transmitted viruses using these particles. Silica-coated magnetic particles were prepared by encapsulating Fe3O4 nanoparticles with tetraethylorthosilicate (TEOS) hydrolysis. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and vibrating sample magnetometer (VSM) were used for particle characterization. The results indicate that silica-coated magnetic particles are spheroid with a narrow hydrodynamic size distribution of about 500nm. VSM data indicates that these particles display paramagnetic behavior with saturation magnetization of about 30emu/g. The adsorption capacities were evaluated with DNA from salmon sperm and RNA of Escherichia coli strain JM109 in the presence of guanidinium thiocyanate. The maximum of adsorption is up to 10.6mg DNA or 7.7mg RNA per 1g of silica-coated magnetic particles with 4M guanidinium thiocyanate (GTC) at pH 5.5 without adding ethanol. The influencing factors were analyzed in term of the adsorption of nucleic acids onto silica-coated magnetic particles. The adsorption capacity in acidic condition is found to be larger than that in alkaline condition and increases with adding equivalent volume of ethanol. A simple method was therefore established to extract nucleic acids of two important transfusion-transmitted viruses from serum and compared with the commercial kits. The results indicate that the extraction method based on silica-coated magnetic particles can be adapted to rapidly and facilely isolate viral nucleic acid for diagnosis of viral infection from serum within 30min, irrespective of genome compositions of virus.

Prevalence of HBc-Ab among HBs-Ag negative healthy blood donors in south of Iran.

Background:The risk of infection with transfusion-transmitted viruses, such as Hepatitis B virus (HBV), has been reduced markedly. However, a zero-risk blood supply remains a popular goal. Anti-hepatitis B core antigen (anti-HBc) is considered to be an effective marker for occult HBV infection, and it has served a significant role in improving blood safety. The purpose of this study was to determine the seroprevalence of anti-HBc antibodies among blood donors.Methods:During a period of six months in 2012, 1000 blood donors in Bandar Abbas were investigated for the presence of HBV infection markers. We used ELISA for the detection of HBsAg and chemiluminescence for the detection of HBsAb and anti-HBc antibodies.Results:The prevalence of positive anti-HBc among the 1000 donors was 8.3%. Almost 2.3% of the donors were reactive for anti-HBc and negative for HBsAg.Conclusions:The study showed that more than 2% of healthy blood donors in Bandar Abbas already have been exposed to HBV, although their HBsAg tests were negative. We suggest screening for anti-HBc to improve the safety of the blood supply.

Donor minipool NAT screening for HBV, HCV, and HIV: a 2-year experience in a private hospital in Saudi Arabia

Blood transfusion is a life-saving approach, although it carries the risk of transfusion-transmitted viruses (TTVs). In Saudi Arabia (SA), nucleic acid amplification test (NAT) has been obligatory for HCV, HBV, and HIV by 2008. Our aim is to evaluate the effectiveness of NAT for detection of TTVs in the blood donated at Saudi German Hospitals (SGH) in SA. A total of 12,437 donor samples from SGH between January 2009 and June 2011 were subjected to routine serologic tests for HBV, HCV, and HIV followed by minipool NAT using Cobas Amplicor analyzer (Roche Diagnostics) for the seronegative samples. Out of 12,032 seronegative plasmas, five (0.042 %) were positive for HCV and two (0.017 %) for HIV-1 by NAT. None of our seronegative donors were NAT positive for HBV, highlighting the value of hepatitis B core antibody detection in donor testing. Our results provide evidence to support the effectiveness of NAT screening to detect TTVs in blood donations.

Le risque infectieux viral chez le polytransfusé : séroprévalence de sept agents viraux dans le centre tunisien

The aim of this study is to evaluate the prevalence of seven transfusion-transmitted viruses in polytransfused adults and children comparatively with a group of healthy control subjects. We studied 107 polytransfused patients (59 adults and 48 children) and 160 control subjects (100 blood donors and 60 children). Immunoenzymatic tests were used for detection of HBs antigen (HBs Ag), antibodies against hepatitis C Virus (anti-HCV), and human immunodeficiency virus (anti-HIV), and IgG antibodies against human cytomegalovirus (IgG anti-CMV), human parvovirus B19 (IgG anti-PB19), and hepatitis E virus (IgG anti-HEV). An immunofluorescent assay was performed for the detection of human herpesvirus 8 antibodies (anti-HHV8). Prevalence of HBs Ag, anti-HCV, anti-HIV, IgG anti-CMV, IgG anti-PB19, IgG anti-HEV, and anti-HHV8 in polytransfused group was 8.4, 4.7, 0, 86.9, 60.7, 28.9, and 47.6%, respectively, and 1.8, 0.6, 0, 86.2, 53.1, 10, and 12.5%, respectively, in the control group. The difference in prevalence between the two groups was statistically significant for HBs Ag (P = 0.01), anti-HCV (P = 0.03), IgG anti-HEV (P < 10(-4)), and IgG anti-HHV8 (P < 10(-4)). Categorization according to age showed that hepatitis B and C risk was limited in adult polytransfused group. HHV8 infection was higher in polytransfused subjects born before the use of leucocyte-depleted blood components. Our results corroborate literature data on the risk of HEV and HHV8 infection by blood transfusion. Hepatitis B vaccination and improvement in screening tests have an important role in reduction of hepatitis B and C risk in transfusion, especially in young polytransfused persons. However, a residual risk of transmitting viral infections persists, and efforts are needed to improve transfusion safety.

Transfusion transmission of highly prevalent commensal human viruses

Anellovirus species Torque teno virus (TTV), Torque teno mini virus (TTMV), and Torque teno midi virus (TTMDV) and flavivirus GBV-C are highly prevalent and genetically diverse chronic human viral infections that have not yet been associated with disease. To determine if these commensal viruses are transmitted by blood transfusions, we genetically analyzed viral species in cryopreserved samples from blood donors and corresponding pre- and posttransfusion samples from recipients enrolled in the Transfusion-Transmitted Viruses Study cohort. All 24 individuals in 12 donor-recipient pairs were infected with TTV, while 16 were infected with TTMV, 15 with TTMDV, and four with GBV-C. None of the 12 informative cases of TTV transfusion or eight cases of TTMV transfusion, where the donor and recipient viruses could be genetically differentiated, resulted in detectable transmissions in which the donor viruses were detected in the recipient by direct sequencing of the polymerase chain reaction products. Of the five informative cases of TTMDV transfusion, including two cases of transfusion into TTMDV-negative recipients, one case of superinfection was seen with both the recipient and the donor viral variants detected in the transfusion recipient for at least 11 days posttransfusion. Three donor-recipient pairs were informative for GBV-C transmission with only one transfusion into a GBV-C-negative recipient resulting in a transiently detected infection. Transmission of the common commensal anelloviruses and GBV-C during transfusion was detected in 2 of 12 already infected or uninfected recipients. Underestimation of the true rate of viral transmission may be due to limitations in detecting donor viral variants present as minority variants in the already infected transfusion recipients.

HBV and HCV viral markers seroperevalence in first-time healthy blood donors refered to transfusion centers of bushehr province, South of Iran (April 2004 to March 2008)

Background The risk of infection by transfusion-transmitted viruses has been reduced remarkably. However, a zero-risk blood supply is still desirable. Hepatitis B (HBV) and Hepatitis C (HCV) viruses are transmitted mainly by parenteral route, following which, a remarkable proportion of infected cases, may progress to chronic hepatitis. In this study we analyzed seroprevalence, demographic and epidemiologic characteristics of positive HBV and HCV cases in first time blood donors of Bushehr province.

Lack of Evidence for Human Herpesvirus–8 Transmission via Blood Transfusion in a Historical US Cohort

Recent studies have found evidence of occasional human herpesvirus (HHV)-8 transmission via blood transfusion. However, because these studies were conducted outside the United States or did not have linked donor-recipient pairs, they have a limited ability to inform US blood-banking policy. We investigated HHV-8 transmission via blood transfusion in the United States by conducting HHV-8 serologic testing among participants of the Transfusion-Transmitted Viruses Study (TTVS), who enrolled during the 1970s. HHV-8 seroprevalence was 2.8% (29/1023) among blood donors, 7.1% (96/1350) among transfusion recipients, 7.7% (46/599) among surgical control patients who did not receive transfusions, and 96.3% (77/80) among control patients with Kaposi sarcoma. One transfusion recipient seroconverted (0.08% [1/1259]), but this patient did not receive any HHV-8-seropositive blood units, suggesting that the infection was not related to blood transfusion. One of the surgical control patients who did not receive transfusions also seroconverted (0.18% [1/556]). Rates of seroconversion were 1.6 per 1000 person-years (95% confidence interval [CI], 0.04-8.9 per 1000 person-years) for the transfusion recipients and 3.6 per 1000 person-years (95% CI, 0.09-20.1 per 1000 person-years) for the surgical control patients who did not receive transfusions (P = .61). Rates of HHV-8 seroconversion in the transfusion and nontransfusion groups were not statistically different, and the historical nature of the cohort (e.g., before leukoreduction) suggests that any current transmission via blood transfusion is rare.

Assessment of safety in neonates for transfusion of platelets and plasma prepared with amotosalen photochemical pathogen inactivation treatment by a 1‐month intravenous toxicity study in neonatal rats

It is estimated that approximately 300,000 neonates undergo transfusions annually. The neonatal immune system is immature, making such patients more susceptible to the effects associated with transfusion-transmitted bacteria, viruses, protozoa, and white blood cells (WBCs). The INTERCEPT Blood System is a photochemical process (PCT) utilizing amotosalen and long-wavelength ultraviolet to inactivate pathogens and WBCs in both platelet (PLT) and plasma components for transfusion. A series of clinical studies has shown PCT PLTs and PCT plasma to be safe and effective for transfusion in adults and pediatric patients. Because clinical studies in neonates are technically difficult and ethically challenging, preclinical toxicologic studies were conducted in neonatal rats to evaluate the safety of PCT blood components for neonates. This study examined daily intravenous administration to neonatal rats of amotosalen in 35 percent:65 percent plasma:InterSol from 1 microg per kg per day (representing 1-unit transfusion) to 457 microg per kg per day (representing multiple transfusions) from Postnatal Day 4 (PND4) to PND31. Rats were observed for viability, clinical signs, and body weights until PND31 and then subjected to pathology evaluation. Hematology, clinical chemistry, and urinalysis data were also collected on PND31. Toxicokinetic parameters were evaluated on PND4 and PND31. There were no amotosalen-related effects on clinical signs, body weight, hematology, clinical chemistry, urinalysis, gross pathology, or histopathology, despite the exposure of neonatal rats to amotosalen concentrations as high as approximately 48 times the standard exposure in adult patients. This study demonstrates the safety of PCT for transfusion in neonatal rats and augments data from other studies and clinical use supporting the use of PCT in neonatal patients.

Scientific Background on the Risk Engendered by Reducing the Lifetime Blood Donation Deferral Period for Men Who Have Sex With Men

The lifetime deferral for men who have sex with men (MSM) has not been harmonized with the 12-month deferral for similar-risk activities through heterosexual contacts. This occurs primarily because of fears of increased transfusion transmission of known sexually and transfusion-transmitted viruses for which donor blood is (eg, HIV) or is not (eg, human herpesvirus 8 [HHV-8]) tested and also of fears of novel agents that may share the epidemiology and long asymptomatic phase of HIV. A 12-month MSM deferral could result in release of 1 HIV-infectious donation every 11 years in the United States. This risk is smaller than the risk from allowing the continued use of pooled whole blood-derived platelets (release of 1 infectious platelet dose every 1.67 years), a risk that is considered "tolerable." Provided that measures to reduce the number of allogeneic-donor exposures to novel pathogens (which may be vector- or food-borne rather than sexually transmitted) are implemented, and the deferral for similar-risk activities through heterosexual contacts is extended to 5 years, a 5-year MSM deferral could be justified because of the interval between emergence of a novel pathogen and introduction of measures to protect the blood supply. Also, provided that measures to protect the blood supply from HHV-8 are implemented, a lifetime MSM deferral could be justified because of the uncertainty about the clinical consequences of transfusion transmission of HHV-8. Because such alternate measures, which would have had a greater impact on safety than the MSM deferral, have not been implemented to demonstrate a consistent approach to safety, maintenance of the current MSM deferral appears to be selectively precautionary and cannot be justified.

Current Risks in Blood Transfusion in Japan

Over the past decades, the incidence of transfusion-transmitted diseases has been dramatically reduced. These reductions have been due to a multifocal approach to the collection, processing, and release of blood components. The estimated risks of transfusion-transmitted hepatitis viruses are now extremely small, but the possibility of infections with emerging pathogens always exists because preventive measures may not be available for all cases. Thus, some patients may be harmed before preventive measures are introduced. Beside transfusion-transmitted infections (TTI), unsolved residual risks such as transfusion-related acute lung injury or incompatible blood components transfusion still exist as major concerns. Continuous efforts toward research on and the prevention of adverse reaction-related blood components must be made to ensure blood safety. The purpose of this article is to introduce the concept of the current risks of transfusion including TTI, review the preventive measures already implemented, and discuss future visions for transfusion safety in Japan.

Trends in Transfusion-Transmitted Viral Infections from 2001 to 2006 in Ibadan, Nigeria

Objective: Screening of blood before transfusion is an effective strategy to reduce transfusion-transmitted viruses. However, reports on viral marker trends among the donor population are scarce. This study looked at trends in the seroprevalence of hepatitis B (HBV) and C (HCV) and human immunodeficiency virus (HIV). Method: This is a retrospective study among blood donors at a tertiary hospital in Nigeria. We used the blood bank records to calculate yearly seroprevalence rates for HBV, HCV and HIV per 100 donations from 2001 to 2006. Results: A total of 33,682 prospective donors were screened, of which 13.2% were positive for HBsAg. The overall seroprevalence rates for HIV and HCV were 7.66% and 3.69%, respectively. HIV seroprevalence rose from 4.25% in 2001 to peak at 12.64% in 2003, before a steep drop to 6.35% in 2004 and a gradual decline to 5.70% in 2006 (p < 0.05). Conclusion: The seroprevalence rates for HIV and HBsAg fluctuated greatly during the study period while the seroprevalence of HCV was consistent. The screening kits used may be partly responsible for these fluctuations. Innovative programs for donor education, with the use of a formal questionnaire in donor selection, are recommended to ensure a safe donor population.

The course of hepatitis C viraemia in transfusion recipients prior to availability of antiviral therapy

Knowing the likely distribution of intervals from hepatitis C infection to first RNA-negativity is important in deciding about therapeutic intervention. Prospectively collected sera and data from the Transfusion-transmitted Viruses Study (1974-1980) provide specific dates of infection and pattern of alanine aminotransferase (ALT) elevations. We examined frequency, timing and correlates of spontaneous resolution for 94 acutely infected transfusion recipients followed for a median of 9.5 months. Later, follow-up sera (>10 years) were available for 27 of the 94 cases from a Veterans Administration (VA) Study (1989-1990). Twenty-five (27%) of the 94 cases were classified as probably resolved during the episode itself. First RNA negativity occurred at 6-50 weeks (median, 19.5 weeks) after infection, and 5-43 weeks (median, 11 weeks) after ALT elevation. Thirteen of the 25 cases remained RNA-negative subsequently; 12 others had 1-6 RNA-positive sera intercalated between first and last RNA-negative results. RNA negativity, therefore, began variably and was interrupted in 12 cases of 25 (48%) by transient RNA-positive sera. Five of these 25 patients who were RNA-negative in the last study specimen had late, Veterans Administration Study follow-up; none showed viraemia. Of the remaining 69 transfusion transmitted virus study recipients, whose last serum was RNA-positive, two cleared viraemia after the last study serum but before late follow-up. Eleven (16%) had 23 intercalated RNA-negative sera before last positivity. RNA status, therefore, needs monitoring for many months before judging the spontaneous outcome as transient negativity may occur. Resolution was significantly more common in women and symptomatic cases; it was not associated with viral load in the infectious donation, HCV genotype, or the recipient's age.