Trends in residual risk of transfusion-transmitted viral infections in France between 1992 and 2000

Prevalence of HIV infection among Chinese voluntary blood donors during 2010-2017: an updated systematic review and meta-analysis

BACKGROUND

Understanding the latest human immunodeficiency virus (HIV) epidemic in voluntary blood donors could be of great value to further increase blood safety in China, as transfusion-transmitted infection places a heavy burden on both infected individuals and the whole society. Therefore, we evaluated the national HIV prevalence of voluntary blood donors in China and characteristics of HIV-infected blood donors.

STUDY DESIGN AND METHODS

We searched literature in Chinese and English concerning the prevalence of HIV infections in Chinese voluntary blood donors from 2010 to 2017, yielding 97 eligible papers. We performed a meta-analysis to calculate pooled HIV prevalence, and characteristics of HIV-infected blood donors were also extracted.

RESULTS

The pooled sample consisted of 21,100,755 voluntary blood donors and 4,755 HIV-infected blood donors. Pooled HIV prevalence of China voluntary blood donors during 2010 to 2017 was 21.02 in 100,000. Pooled HIV prevalence varied in different provinces, showing greater severity in Southwest, Northwest, and South China. Subgroup analysis also showed a significantly increasing trend from 2010 to 2017. The majority of HIV-infected blood donors in China were male, young, unmarried, nonlocal residents, receiving 12 years or less of schooling, and first-time donors. Nearly 90% of HIV-infected blood donors acquired their infections through sexual contact.

CONCLUSION

The prevalence of HIV increased in China among voluntary blood donors during 2010 to 2017, highlighting the risk of HIV transmission by transfusion. Blood centers and public health services should improve screening and intervention programs targeting voluntary blood donors and expand education on blood safety in areas experiencing severe epidemics and among high-risk populations.

Effectiveness of blood donor screening by HIV, HCV, HBV-NAT assays, as well as HBsAg and anti-HBc immunoassays in Germany (2008-2015)

BACKGROUND AND OBJECTIVES

In Germany, in addition to standard blood donor screening, further mandatory tests were introduced for HCV-RNA, HIV-1-RNA and for anti-HBc. Screening for HBV-DNA is optional. This study investigates the benefits of these additional tests for the detection of HIV, HCV, and HBV infections among German blood donors.

MATERIALS AND METHODS

From 2008 to 2015 we collected data on blood donations exclusively testing NAT positive (NAT yield) or reactive in only one of the screening assays. Assuming a Poisson distribution, we calculated NAT yield/reactive only rates on a per donation basis (number of yield/reactive only cases divided by the number of donations tested in the period under review) with 95% confidence intervals.

RESULTS

Responding establishments covered 95% of the donations. We identified 20 HIV-1-NAT, 61 HCV-NAT and 29 HBV-NAT yield cases among approximately 46 million blood donations tested corresponding to 0·43 HIV-1 NAT, 1·32 HCV-NAT, and 0·64 HBV-NAT yield cases per million blood donations tested. For one HBsAg reactive only case and 23 anti-HBc reactive only cases in repeat donors, infection was confirmed by ID-NAT which translates into 0·02 and 0·55 cases per million donations tested. During the 8-year-observation period, one HIV-1, no HCV and four HBV transmissions associated with donations in the viremic pre-seroconversion window period were reported.

CONCLUSION

Annually, NAT screening alone detected 2·5 HIV-1, 7·6 HCV, and 3·6 HBV infectious donations; anti-HBc screening alone identified 2·9 infectious donations of repeat donors with occult HBV infection. Overall, the survey results support that the currently practiced donor HIV/HCV/HBV screening strategy in Germany does ensure a high standard of blood safety.

Prevalence and risk factors of HTLV-1/2 and other blood borne infectious diseases among blood donors in Yaounde Central Hospital, Cameroon

Introduction

Transfusion-transmissible infectious microorganisms including bacteria and viruses are among the greatest threats to blood safety for the recipient. The prevalence and risk factors of HTLV-1/2 and other blood borne infectious diseases were determined among blood donors in Yaounde Central Hospital, Cameroon.

Methods

Design: cross sectional study. Setting: The blood bank unit of Yaounde Central Hospital, Cameroon. Subjects: a consecutive sample of 265 apparently healthy adult blood donors. Investigations: Search for the presence of hepatitis B surface antigen (AgHBs) and antibodies to human T-lymphotropic virus type 1 (anti-HTLV-1/2), human immunodeficiency virus (anti-HIV), hepatitis C virus (anti-HCV) and syphilis and to determine the epidemiological correlates, if any, in the occurrence of HTLV infection.

Results

77 (29.05%) of the blood donors had serological evidence of infection with at least one pathogen and 4 (5.2%) had dual infections with HTLV-1/2. The overall prevalence of HTLV-1/2, HIV, HCV, HBV and syphilis were 5.7%, 5.3%, 2.6%, 11.7%, 3.8% respectively. Surgical history (Chi²=4.785; P=0.029), scarification (Chi²=6.359; P = 0.012), piercing (Chi² = 16.353; P = 0.000) and intravenous drug use (Chi² = 15.660; P = 0.000) were identified as risk factors for HTLV-1/2 infection.

Conclusion

A relative high prevalence of viral infections and syphilis was recorded among the study participants especially for HTLV-1/2 for which none blood donation is routine screened in our set up. Therefore, a routine screen of blood prior to transfusion should include anti-HTLV-1/2 tests.

Residual risk of transmission of human immunodeficiency virus and hepatitis C virus infections by blood transfusion in northern Brazil

BACKGROUND

Nucleic acid test (NAT) blood screening for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) was introduced in northern Brazil in July 2012. There are several Brazilian articles that have evaluated transfusion transmission risks for HIV and HCV. However, to our knowledge, this article is the first to evaluate the impact of HIV and HCV NAT implementation for blood screening in northern Brazil. The aim of this study was to determine the prevalence and incidence rates of HIV and HCV among blood donors and to compare the residual risk of transfusion transmission of these infections, before (2009-2011) and after (2012-2014) NAT implementation.

STUDY DESIGN AND METHODS

HIV and HCV prevalence and incidence were calculated based on rates of confirmed positive samples. Residual risk estimates were based on the incidence and window model described previously. Logistic and Poisson regressions were used in the statistical analysis. A p value of not more than 0.05 was considered significant.

RESULTS

HIV and HCV prevalence were 209.9 and 66.3 per 100,000 donations, respectively. Residual risk for HIV and HCV decreased significantly throughout the two study periods, mainly for HCV in which the reduction was one in 169,492 to one in 769,231 donations. For HIV, the decrease was one in 107,527 to one in 769,231 donations. HIV and HCV incidence rates were 21.13 and 3.06 per 100,000 persons/year before NAT and 14.03 and 2.65 per 100,000 persons/year after NAT.

CONCLUSION

The HIV and HCV NAT implementation significantly increased the transfusion safety in northern Brazil, bringing benefits to recipients due to better quality of blood products produced.

Three-Year Experience in NAT Screening of Blood Donors for Transfusion Transmitted Viruses in Croatia

Background

Croatia implemented individual donation (ID)-NAT testing of blood donors in 2013 for three viruses HBV, HCV, and HIV-1 as a mandatory test for all blood donors. This study assessed the impact of NAT screening 3 years after its implementation.

Methods

A total of 545,463 donations were collected and screened for HBV, HCV, and HIV-1 using the Procleix Ultrio Plus Assay. All initially reactive (IR) NAT samples were retested in triplicate and, if repeatedly reactive (RR), NAT discriminatory assay (dNAT) was performed. ID-NAT positive donations were confirmed by RT-PCR on the COBAS AmpliPrep/TaqMan platform.

Results

Out of 545,463 samples tested, 108 (0.02%) were RR in NAT. There were 82 (75,9%) HBV reactive, 16 (14.8%) HCV reactive, and 10 (9.3%) HIV-1 reactive samples. 51 (47.2%) samples were ID-NAT positive only. Out of these 51 NAT yield cases, 1 window period HIV-1 and 50 occult HBV infections (OBI) were determined. There were only two potential HBV DNA transmissions from OBI donors.

Conclusion

The implementation of NAT screening for three viruses has improved blood safety in Croatia. During the 3-year period, 1 window period HIV-1 and a number of occult HBV donations were identified.

Incidence and Residual Risk of HIV, HBV and HCV Infections Among Blood Donors in Tehran

Estimation of residual risk is essential to monitor and improve blood safety. Our epidemiologic knowledge in the Iranian donor population regarding transfusion transmitted viral infections (TTIs), is confined to a few studies based on prevalence rate. There are no reports on residual risk of TTIs in Iran. In present survey, a software database of donor records of Tehran Blood Transfusion Center (TBTC) was used to estimate the incidence and residual risk of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections, by applying the incidence rate/window period (IR-WP) model. A total of 1,207,155 repeat donations was included in the analysis and represented a mean of 8.4 donations per donor over 6 years. The incidence amongst repeat donors was estimated by dividing the number of confirmed seroconverting donors by the total number of person-years at risk. The residual risk was calculated using the incidence/window period model. Incidence rate and residual risk for HBV, HCV and HIV infections were calculated for total (2005-2010) and two consecutive periods (2005-2007 and 2008-2010) of the study. According to the IR-WP model, overall residual risk for HIV and HCV in the total study period was 0.4 and 12.5 per million units, respectively and for HBV 4.57/100,000 donations. The incidence and residual risk of TTIs, calculated on TBTC's blood supply was low and comparable with developed countries for HIV infection but high for HCV and HBV infections. Blood safety may therefore be better managed by applying other techniques like nucleic acid amplification tests.

Influence of Clinical and Economical Factors on the Expert Rating of Appropriateness of Preoperative Use of Recombinant Erythropoietin in Elective Orthopedic Surgery Patients

To evaluate the relative impact of clinical factors and health care environment resources on the expert ratings of appropriateness of preoperative erythropoietin in elective orthopedic surgery, the authors analyzed 6905 individual votes on 496 clinical scenarios from 14 experts, applying a multivariate logistic model. Sixty-six percent of the indications were appropriate when resource constraints (RC) were not considered and 53% when they were, resulting in a drop in the median vote of 2 points on a 9-point scale (P < 0.05). Initial hemoglobin level, expected perioperative blood loss, and RC were by far the most significant contributors to the model (P < 0.01), but other factors (i.e., clinical specialty of the expert, prior history of transfusion reactions, patient age, cardiovascular disease, anemia of chronic disease) also contributed significantly (P< 0.01). For assessing appropriateness of care, this study confirms the need for detailed clinical scenarios and a multidisciplinary panel carefully selected to reflect those involved in the interventions under consideration.

[Seroconversion in response to a reinforced primary hepatitis B vaccination in children with cancer]

INTRODUCTION

Immune response against vaccine antigens may be impaired in children with cancer. The aim of this study was to evaluate the seroconversion response against hepatitis B vaccination (HBV) at the time of chemotherapy onset and/or remission in children with cancer.

PATIENTS AND METHOD

Prospective, two-centre, controlled, non-randomised study conducted on children recently diagnosed with cancer, paired with healthy subjects. Cases received HBV at time 0, 1 and 6 months with DNA recombinant HBV at a dose of 20 and 40 μg if < or > than 10 years of age, respectively, at the time of diagnosis for solids tumours and after the remission in case of haematological tumours. Controls received the same schedule, but at of 10 and 20 μg doses, respectively. HBs antibodies were measured in serum samples obtained at 2, 8 and 12 months post-vaccination. Protective titres were defined as > 10 mIU/ml at 8th month of follow up.

RESULTS

A total of 78 children with cancer and 25 healthy controls were analysed at month 8th of follow up. Seroconversion rates in the cancer group reached 26.9%, with no differences by age, gender or type of tumour (P = .13, .29, and .44, respectively). Control group seroconversion was 100% at the 8th month, with P < .0001 compared with the cancer group. At month 12 of follow up, just 31.9% of children with cancer achieved anti-HBs antibodies > 10 mIU/ml.

CONCLUSIONS

Vaccination against hepatitis B with three doses of DNA recombinant vaccine at an increased concentration, administrated at the time of onset of chemotherapy and/or remission provided an insufficient immune response in a majority of children with cancer. More immunogenic vaccines should be evaluated in this special population, such as a third generation, with more immunogenic adjuvants, enhanced schedules at 0, 1, 2, 6 month, evaluation of antibody titres at month 8 and 12h to evaluate the need for further booster doses.

Molecular HIV screening

Nuclear acid testing is more and more used for the diagnosis of infectious diseases. This paper focuses on the use of molecular tools for HIV screening. The term 'screening' will be used under the meaning of first-line HIV molecular techniques performed on a routine basis, which excludes HIV molecular tests designed to confirm or infirm a newly discovered HIV-seropositive patient or other molecular tests performed for the follow-up of HIV-infected patients. The following items are developed successively: i) presentation of the variety of molecular tools used for molecular HIV screening, ii) use of HIV molecular tools for the screening of blood products, iii) use of HIV molecular tools for the screening of organs and tissue from human origin, iv) use of HIV molecular tools in medically assisted procreation and v) use of HIV molecular tools in neonates from HIV-infected mothers.

Prevalence of serologic markers for hepatitis B and C viruses in Brazilian blood donors and incidence and residual risk of transfusion transmission of hepatitis C virus

BACKGROUND

We evaluate the current prevalence of serologic markers for hepatitis B virus (HBV) and hepatitis C virus (HCV) in blood donors and estimated HCV incidence and residual transfusion-transmitted risk at three large Brazilian blood centers.

STUDY DESIGN AND METHODS

Data on whole blood and platelet donations were collected from January through December 2007, analyzed by center; donor type; age; sex; donation status; and serologic results for hepatitis B surface antigen (HBsAg), antibody to hepatitis B core antigen (anti-HBc), and anti-HCV. HBV and HCV prevalence rates were calculated for all first-time donations. HCV incidence was derived including interdonation intervals that preceded first repeat donations given during the study, and HCV residual risk was estimated for transfusions derived from repeat donors.

RESULTS

There were 307,354 donations in 2007. Overall prevalence of concordant HBsAg and anti-HBc reactivity was 289 per 100,000 donations and of anti-HCV confirmed reactivity 191 per 100,000 donations. There were significant associations between older age and hepatitis markers, especially for HCV. HCV incidence was 3.11 (95% confidence interval, 0.77-7.03) per 100,000 person-years, and residual risk of HCV window-phase infections was estimated at 5.0 per million units transfused.

CONCLUSION

Improvement in donor selection, socioeconomic conditions, and preventive measures, implemented over time, may have helped to decrease prevalence of HBV and HCV, relative to previous reports. Incidence and residual risk of HCV are also diminishing. Ongoing monitoring of HBV and HCV markers among Brazilian blood donors should help guide improved recruitment procedures, donor selection, laboratory screening, and counseling strategies.

Residual risk of transfusion-transmitted infection with human immunodeficiency virus, hepatitis C virus, and hepatitis B virus in Korea from 2000 through 2010

BACKGROUND

Despite screening blood donations with advanced technologies and improved donor screening, the risk of transfusion-transmitted infections persists. This risk is mainly due to blood donations collected during the window period. A precise estimate of the transfusion risk of viral infection will help to determine the effect of new and current safety measures and to prioritize and allocate limited resources. Therefore, we estimated the risk of transfusion-transmitted viral infection in blood donations collected in Korea from 2000 to 2010.

METHODS

Blood donations collected at 16 blood centers were tested for HIV, HCV, and HBV to estimate the residual risk of transfusion-transmitted viral infection. The residual risk was calculated in two-year periods using the incidence/window model. The incidence rates for HIV/HCV and the confirmed positive rate for HIV/HCV in first-time and repeat donors were compared.

RESULTS

The residual risks for HIV in 2004/2005 and 2009/2010 were 1 in 1,080,244 and 1 in 1,356,547, respectively. The risks for HCV in 2000/2001 and 2009/2010 were 1 in 81,431 and 1 in 2,984,415, and the risks for HBV in 2000/2001 and 2009/2010 were 1 in 45,891 and 1 in 43,666. These estimates indicate that the residual risks for HCV in Korea have declined 36.6-fold, and those for HIV and HBV have not improved significantly, compared to previous estimates. The odds ratios for HCV and HBV positivity in first-time donors compared to repeat donors were 11.8 and 19.6, respectively.

CONCLUSIONS

The residual risk of HCV declined over the last decade due to improved screening reagents, implementation of the nucleic acid amplification test, and tight application of strict donor selection procedures. Current residual risk estimates for HIV and HCV in Korea are extremely low, but the risk for HBV is still high; therefore, urgent measures should focus on decreasing the residual risk of HBV. Despite the introduction of more sensitive assays in blood screening, several other factors may influence the actual residual risk of transfusion-transmitted infection. A continuous monitoring of residual risk of transfusion-transmitted infection is crucial in managing blood safety.

Bayesian evaluation of the human immunodeficiency virus antibody screening strategy of duplicate enzyme-linked immunosorbent assay in Xuzhou Blood Center, China

BACKGROUND

Accurate estimation of the risk of human immunodeficiency virus (HIV) infection through transfusion is essential for monitoring blood safety. The risk, however, is so low that it can only be estimated by mathematical modeling. With the Bayesian dependence model, this study evaluates the HIV antibody screening strategy of duplicate enzyme-linked immunosorbent assay (ELISA) in Xuzhou Blood Center and therefore estimates part of the total risks of transfusion-transmitted HIV infection.

STUDY DESIGN AND METHODS

Data from Xuzhou Blood Center between 2004 and 2008 were used. Information was obtained on donor profiles and screening and confirmatory test results. The portion of the risks of HIV infection through transfusion concerned was estimated by evaluating the screening algorithm in terms of its accuracy and predictive power with the Bayesian dependence model.

RESULTS

A total of 234,602 donations from voluntary blood donors in Xuzhou Blood Center were screened for HIV antibody. For the study screening algorithm, its sensitivity, specificity, false-positive predictive value (FPPV), and false-negative predictive value (FNPV) were 0.9951 (95% Bayesian credible interval [BCI], 0.9763-0.9997), 0.9991 (95% BCI, 0.9990-0.9992), 0.9647 (95% BCI, 0.9018-0.9923), and 1.52 × 10(-7) (95% BCI, 7.31 × 10(-9) -1.15 × 10(-6) ), respectively. For the positive detection rate (9.60 × 10(-4) ) and FPPV (0.9647), the differences between their own Bayesian median estimates and real values were 2.70 × 10(-5) and -0.0033, respectively.

CONCLUSIONS

The HIV antibody screening algorithm of duplicate ELISA is well evaluated in its accuracy and predictive power with the Bayesian dependence model. The FNPV measures the part of the risks of transfusion-associated HIV transmission concerned.

Sensitivity of two hepatitis B virus, hepatitis C virus (HCV), and human immunodeficiency virus (HIV) nucleic acid test systems relative to hepatitis B surface antigen, anti-HCV, anti-HIV, and p24/anti-HIV combination assays in seroconversion panels

BACKGROUND

Accurate determination of the infectious window period (IWP) that remains with individual-donation (ID) or minipool (MP) NAT compared to those with serology assays is essential for residual risk estimations.

STUDY DESIGN AND METHODS

The relative sensitivity of the Procleix Tigris system (Gen-Probe/Chiron) used in ID-NAT format and cobas s 201 (Roche Molecular Systems) applied in 1:6 diluted samples to mimic six-minipool (MP6) nucleic acid test (NAT) was assessed by quadruplicate testing of five seroconversion panels per marker. A mathematical analysis based on the log-linear increase of viremia in the ramp-up phase, as established with bDNA 3.0 assays enabled estimation of the IWP for human immunodeficiency virus (HIV) and hepatitis B virus (HBV) assays.

RESULTS

The mean IWPs were Tigris HIV RNA 5.5 days, s 201 (1:6) HIV RNA 7.4 days, GenScreen Plus p24/anti-HIV 17.8 days, PRISM anti-HIV 19.0 days, Tigris HBV DNA 20.6 days, s 201 (1:6) HBV DNA 22.6 days, Bio-Rad hepatitis B surface antigen (HBsAg) 37.8 days, and PRISM HBsAg 35.5 days. At estimated 50 percent NAT seroconversion rates, s 201 (1:6) and Tigris showed mean window-period reduction times (WPRTs) of 30.5 to 35.5 days to hepatitis C virus antibody (anti-HCV) assays, 10.4 to 13.5 days to anti-HIV, or combination p24/anti-HIV assays and 12.8 to 17.2 days to HBsAg assays.

CONCLUSIONS

Tigris ID-NAT detected HIV RNA 2 days earlier than s 201 MP6-NAT, but the difference in sensitivity between the two NAT systems was not significant in HBV seroconversion panels. Insufficient seroconversion samples were available for reliable modeling of WPRT in early HCV infection, but 1.4 to 2.0 days could be predicted by translating analytical sensitivity data. Both multiplex NAT systems demonstrate significant WPRTs compared to (combined) antigen and antibody assays.

An autoregressive integrated moving average model for short-term prediction of hepatitis C virus seropositivity among male volunteer blood donors in Karachi, Pakistan

AIM: To identify the stochastic autoregressive integrated moving average (ARIMA) model for short term forecasting of hepatitis C virus (HCV) seropositivity among volunteer blood donors in Karachi, Pakistan.

METHODS: Ninety-six months (1998-2005) data on HCV seropositive cases (1000^-1× month^-1) among male volunteer blood donors tested at four major blood banks in Karachi, Pakistan were subjected to ARIMA modeling. Subsequently, a fitted ARIMA model was used to forecast HCV seropositive donors for 91-96 mo to contrast with observed series of the same months. To assess the forecast accuracy, the mean absolute error rate (%) between the observed and predicted HCV seroprevalence was calculated. Finally, a fitted ARIMA model was used for short-term forecasts beyond the observed series.

RESULTS: The goodness-of-fit test of the optimum ARIMA (2,1,7) model showed non-significant autocorrelations in the residuals of the model. The forecasts by ARIMA for 91-96 mo closely followed the pattern of observed series for the same months, with mean monthly absolute forecast errors (%) over 6 mo of 6.5%. The short-term forecasts beyond the observed series adequately captured the pattern in the data and showed increasing tendency of HCV seropositivity with a mean ± SD HCV seroprevalence (1000^-1× month^-1) of 24.3 ± 1.4 over the forecast interval.

CONCLUSION: To curtail HCV spread, public health authorities need to educate communities and health care providers about HCV transmission routes based on known HCV epidemiology in Pakistan and its neighboring countries. Future research may focus on factors associated with hyperendemic levels of HCV infection.

HIV type 1 infection among Ethiopian immigrants to Israel: enhanced in vitro antibody stimulation for estimating the length of the window period

The window period between infection and seroconversion varies based on viral genetics, dose and route of transmission, host genetics, and environmental factors. The in vitro Stimmunology blood pretreatment assay was utilized to promote the synthesis of HIV-specific antibodies in efforts to define the window period between infection and seroconversion. Ethiopians seeking immigration to Israel while in refugee camps provided a unique cohort to perform a comparative analysis of the window period between HIV-1 infection and diagnosis utilizing conventional Ab-ELISA and our laboratory established an in vitro Stimmunolog assay. This population was considered unique due to its exposure to an environment with a high seroprevalence rate for a defined period of time. Unlinked blood samples were tested and validated before and after Stimmunology. Diagnostic screening was conducted in Israel. A total of 285 and 537 random samples were tested from the 1992 and 1998 immigrant population, respectively. Analysis of HIV prevalence, incidence, and window period length among the immigrants was measured by comparing results obtained on samples prior to and following analysis by Stimmunology as compared with standard ELISA-based assay. This novel assay that promotes the in vitro stimulation of antibody synthesis led to the diagnosis of 2.7% and 0.36% of the 1992 and 1998 immigrant groups, respectively, as HIV infected individuals during the window period. Using mathematical modeling, the length of the window period in the surveyed population was estimated to range from 2 to 5 months. Stimmunology-aided detection of early seronegative HIV-infected individuals provided a reliable and consistent mode of identifying infection in seronegative HIV-1-infected individuals. Applying mathematical modeling to the data obtained enabled us to define the window period length, which was found to extend beyond previous estimates. These results suggest a need for the reevaluation of the techniques that are employed to assess the true incidence and prevalence of HIV-1 infection, especially in populations within sub-Saharan Africa.

Human immunodeficiency virus type 1 incidence among blood donors in France, 1992 through 2006: use of an immunoassay to identify recent infections

BACKGROUND

In France, blood donations found to be positive for the presence of human immunodeficiency virus type 1 (HIV-1) are further tested to detect recent infections (< or =180 days) using an enzyme immunoassay (EIA-RI) developed in 2002. The characteristics of recently infected donors, estimates of HIV-1 incidence, and the residual risk of transfusion-transmitted HIV-1 are presented, in both first-time and repeat donors.

STUDY DESIGN AND METHODS

Of the 1027 donations found to be HIV-1-positive between 1992 and 2006, a total of 459 could be retrospectively tested with the EIA-RI. Multivariate analysis was performed to determine the donor characteristics associated with recent infection. Incidence rates and residual risk obtained with the EIA-RI were compared to classical cohort estimates derived from repeat donor histories.

RESULTS

Of the 459 HIV-1-positive donors studied, 105 (22.9%; 95% confidence interval [CI], 19.2-27.0) were identified as recently infected. Factors independently associated with recent infection were repeat donor status (adjusted odds ratio [AOR], 4.0; 95% CI, 2.4-6.9) and non-B subtypes (AOR, 2.0; 95% CI, 1.2-3.6). Incidence decreased from 4.3 (95% CI, 1.9-9.4) in 1992 through 1994 to 1.3 (95% CI, 0.6-2.8) per 10(5) in 2004 through 2006 in first-time donors and from 3.2 (95% CI, 2.0-5.0) to 0.8 (95% CI, 0.4-1.4) per 10(5) in repeat donors. Incidence and residual risk estimates were similar to those obtained with the classical cohort method.

CONCLUSION

This study suggests that the EIA-RI can be used to estimate HIV-1 incidence in a population with low HIV incidence. The estimated HIV-1 incidence in the blood donor population confirms the extremely low risk (1 in 3,350,000 donations) of HIV-infected blood donations entering the blood supply in France.

Experience of German Red Cross blood donor services with nucleic acid testing: results of screening more than 30 million blood donations for human immunodeficiency virus-1, hepatitis C virus, and hepatitis B virus

BACKGROUND

The risk of transfusion-transmitted human immunodeficiency virus-1 (HIV-1), hepatitis C virus (HCV), and hepatitis B virus (HBV) infections is predominantly attributable to donations given during the early stage of infection when diagnostic tests may fail. In 1997, nucleic acid amplification technique (NAT)-testing was introduced at the German Red Cross (GRC) blood donor services to reduce this diagnostic window period (WP).

STUDY DESIGN AND METHODS

A total of 31,524,571 blood donations collected from 1997 through 2005 were screened by minipool NAT, predominantly with pool sizes of 96 donations. These donations cover approximately 80 percent of all the blood collected in Germany during that period. Based on these data, the WP risk in the GRC blood donor population was estimated by using a state-of-the-art mathematic model.

RESULTS

During the observation period, 23 HCV, 7 HIV-1, and 43 HBV NAT-only-positive donations were detected. On the basis of these data and estimated pre-NAT infectious WPs, the residual risk per unit transfused was estimated at 1 in 10.88 million for HCV (95% confidence interval [CI], 7.51-19.72 million), 1 in 4.30 million for HIV-1 (95% CI, 2.39-21.37 million), and 1 in 360,000 for HBV (95% CI, 0.19-3.36 million). Based on observed cases of breakthrough infections, the risk of transfusion-related infections may be even lower.

CONCLUSION

The risk of a blood recipient becoming infected with HCV, HIV-1, or HBV has reached an extremely low level. Introduction of individual donation testing for HCV and HIV-1 would have a marginal effect on interception of WP donations.

French national survey of inpatient adverse events prospectively assessed with ward staff

OBJECTIVES

To estimate the incidence of adverse events in medical and surgical activity in public and private hospitals, and to assess the clinical situation of patients and the active errors.

DESIGN

Prospective assessment of adverse events by external senior nursing and doctor investigators with ward staff.

SETTING

Random three-stage stratified cluster sampling of stays or fractions of stay in a 7-day observation period for each ward.

PARTICIPANTS

8754 patients observed in 292 wards in 71 hospitals, over 35,234 hospitalisation days.

MAIN OUTCOME MEASURES

Number of adverse events in relation to number of days of hospitalisation.

RESULTS

The incidence density of adverse events was 6.6 per 1000 days of hospitalisation (95% CI 5.7 to 7.5), of which 35% were preventable. Invasive procedures were the source of half the adverse events, of which 20% were preventable. Adverse events related to the psychological sphere and pain were mostly considered as preventable. Ward staff found it difficult to assess the role of care management in the occurrence of adverse events: 41% of adverse events were expected because of the disease itself, and could have occurred in the absence of the related medical management.

CONCLUSION

At the national level in France, every year 120,000-190,000 adverse events during hospitalisation can be considered as preventable. Areas such as perioperative period and geriatric units should receive closer attention. As adverse events occurred more commonly in vulnerable patients, who are not specifically targeted by clinical guidance, practising evidence-based medicine is not likely to prevent all cases. Therefore clinical risk management should prioritize empowerment of local staff, provision of favourable conditions within the organisation, and staff training based on simple tools appropriate for ward-level identification and analysis of adverse events.

An incident case-control study of modes of hepatitis C virus transmission in France

PURPOSE

Risk factors for hepatitis C virus (HCV) infection have rarely been estimated using incident case-control studies in the "general" population. We undertook a case-control study of incident HCV infection to identify persistent modes of transmission in France.

METHODS

Two types of case-patients were included: (1) repeat blood donors who seroconverted between 1998 and 2001 (with a last negative third-generation test reported from 1995 or after) and (2) seroconverters referred to hepatology departments in 2000 through 2001. For each case-patient, four age- and sex-matched controls were randomly selected from the population of occurrence. Data on risk factors were recorded for each case-patient's and matched control's referent exposure period (between last negative and first positive tests).

RESULTS

Sixty-four case-patients and 227 controls were included. In univariate analysis, endoscopy (matched odds ratios [mORs] = 8.0; 95% confidence intervals [CI] = 2.3-27.2), general anesthesia (mOR = 5.6; 95% CI = 2.2-14.7), tattooing or body piercing (mOR = 8.8; 95% CI = 1.7-44.1), and intravenous (IV) drug use (p < 0.0001; mOR not defined) were associated with HCV seroconversion. In multivariate analysis, risk factors associated with HCV seroconversion were drug use (adjusted OR [aOR] = 109.0; 95% CI = 11.7-1015.8), digestive endoscopy (aOR = 5.7; CI = 1.4-23.8), and invasive radiology procedures (aOR = 11.6; CI = 1.7-78.5).

CONCLUSIONS

The results showed the continuing major role of IV drug use and suggested that transmission related to invasive health care remained a potential source of new HCV infection between 1995 and 2001.

Trends in HIV prevalence in blood donations in Europe, 1990-2004

INTRODUCTION

The comparison of HIV prevalence among blood donations in European countries provides an indication of the relative safety of the blood supply in different countries and over time.

METHODS

Data between 1990 and 2004 on annual numbers of blood donations and HIV prevalence in blood donations were collected from national correspondents in the 52 countries of the World Health Organization European Region. Data are presented for three geographic areas: West, Centre and East.

RESULTS

Since 1990, the number of blood donations has declined by 43% in the East and by 26% in the Centre, while remaining relatively stable in the West. In 2004, the number of blood donations was more than twice as high in the West in comparison with the East and the Centre. Over the same period, HIV prevalence among blood donations increased dramatically in the East, remained stable in the Centre and declined in the West. Since 2001, HIV prevalence levels of more than 10 per 100 000 donations were reported from six countries in the East (with a high of 128/100 000 in Ukraine), whereas in the rest of Europe the reported national HIV prevalence levels were lower than 10/100 000 donations. The prevalence of HIV was much lower among donations from repeat donors than from first-time donors.

CONCLUSION

In some eastern European countries public health interventions, such as deferring individuals at risk of HIV infection from donating blood and constituting a pool of regular donors, are urgently needed to assure the safety of the blood supply.

Diversity and origin of hepatitis C virus infection among unpaid blood donors in the Netherlands

BACKGROUND

To improve transfusion policy and to increase understanding of the spread of hepatitis C virus (HCV) in the general population, HCV infections among voluntary Dutch blood donors were examined with molecular epidemiologic techniques.

STUDY DESIGN AND METHODS

During 6 years, 1997 through 2002, confirmed anti-HCV-positive donors were interviewed on HCV-associated risk behavior with a standardized questionnaire. Additionally, HCV isolates were genotyped, partially sequenced, and compared to sequences obtained from Dutch injecting drug users (IDUs).

RESULTS

HCV prevalence and incidence rates among Dutch donors were extremely low; the residual risk of transmitting HCV was calculated to be 1 in 30 million donations. Former IDUs (21%), transfusion recipients (30%), and immigrants (>12%) were identified as major HCV risk groups. Cryptogenic transmission caused 18 percent of infections among new donors and all infections among repeat donors. Compared to IDUs, genotype distribution among donors was highly diverse; major subtypes were 3a (27%), 1a (24%), 1b (24%), 2a/b (10%), and 4 (9%). Half of the donors were infected with IDU-related subtypes 1a and 3a, whereas subtype 1b mainly spread via blood transfusion and various other nosocomial modes of transmission in the past. HCV infections acquired in endemic countries could be clearly identified based on genotype.

CONCLUSION

Different modes of transmission are linked to infections with certain HCV subtypes, suggesting separate HCV epidemics, but spillover between different risk groups underlines the value of molecular epidemiologic techniques to gain insight into the origin and dynamics of HCV infections on a population level.

Residual risk of HIV, HVB and HCV transmission by blood transfusion between 2002 and 2004 at the Abidjan National Blood Transfusion Center

The assessment of the viral residual risk from blood products is an assessment indicator of the quality management system and of the availability process of these products. Assessments of HIV, HBV and HCV viruses transmission risks through blood transfusion are calculated after the setting of a quality approach at the Abidjan NBTC. The method used estimates the risk of a donation made during a period immunologically silent. The residual risks for HIV, HBV, and HCV viruses have been estimated by multiplying the incidence rate for 100,000 people per year by the respective durations of the serological windows. The data received from the Abidjan Center's information processing system (Progesa 4.4d of MAK SYSTEM) go from 2002 to 2004 period. The residual risks are 1/5780 donations for HIV and 1/406 donations for the HCV, then 1/383 donations for the HBV. The residual risk for the HIV is almost four times reduced compared to that of 1997. The results show not only the importance of the transmission risk of HIV, HBV and HCV viruses through blood products, but also the necessity to set a quality management system in endemic countries of Sub-Saharan Africa.

Transfusion recipient identification

Recent reports from different haemovigilance systems indicate that errors in the whole-blood transfusion chain - from initial recipient identification to final blood administration - occur with a frequency of approximately 1 in 1000 events. Although mistakes occur also within the blood transfusion service, about two-thirds of errors are associated with incorrect blood recipient identification at the patient's bedside. To prevent the potentially fatal consequences of such mistakes, specific tools have been developed, including patient identification bracelets with barcodes and/or radio frequency identification devices, mechanical or electronic locks preventing access to bags assigned to other patients, and palm computers suitable for transferring blood request and administration data from the patient's bedside to the blood transfusion service information system in real time. The effectiveness of these systems in preventing mistransfusion has been demonstrated in a number of studies.

[Application of pre- and post-transfusion virological controls prior to the suppression of their recommendation]

In 1996, due to a residual risk of transfusion-transmitted virus, a circular of the French Health Authorities (DGS/DH n degrees 96-609) recommended proposing to recipients of cellular blood products a test for antibodies to human immunodeficiency virus (HIV) and for antibodies to hepatitis C virus, before and three months after transfusion. We have evaluated the application of this recommendation throughout the whole transfused population of a French Hospital over a three month period. In addition, this study allowed us to establish the vaccination status against hepatitis B virus (HBV) infection in this exposed population including transfusion and nosocomial risks. The results showed a failure in the application of the 1996 circular and confirmed the validity of the abrogation of this circular by a recent circular (11 January 2006) of the French health authorities. It also showed that only a minority of patients needing a vaccination against HBV were afforded such treatment during their hospitalization.

Decline in HCV testing and compliance with guidelines in patients of Sentinelles general practitioners, 1996–2002

Between 1996 and 2002, the French Sentinelles Network observed a more than 2-fold decline in the annual rate of hepatitis C virus (HCV) screening tests prescribed by general practitioners. During this period it droped from 1080 to 450 per 100,000 inhabitants. The proportion of HCV-positives increased from 9.7% to 12.9% between 1996 and 1998 but declined steadily afterwards, reaching 7% in 2002. The majority of HCV-positive patients were men (57%), 38% were aged 30-39 years and 45% were injecting drug users. Two French guidelines for HCV screening were issued in 1997 and 2001. Of the 3462 patients with a known HCV test result, 27.4% were offered following the 1997 guidelines, among which 23.7% were HCV-positive. Of the same 3462 patients, 36.8% were offered following the extended definition of the risk group in the 2001 guidelines, among which 19.9% were positive. The percentage of subjects tested with no biological sign or clinical symptom and no HCV risk factor varies from 11% to 26% showing that SGPs carry out a targeted screening even if they deviate from the strict recommendations. Of the HCV-positive patients, 14% did not meet any criteria of the guidelines suggesting a lack of sensitivity in the current definition of patients recommended for testing.

Is an assay for simultaneous detection of hepatitis C virus core antigen and antibody a valuable alternative to nucleic acid testing?

BACKGROUND

A new enzyme immunoassay based on the simultaneous detection of nucleocapsid proteins of hepatitis C virus (HCV) and anti-HCV (Monolisa HCV antigen-antibody Ultra, Bio-Rad) was evaluated as an alternative to nucleic acid testing (NAT) for the diagnosis of HCV infection during the window period in blood donations.

STUDY DESIGN AND METHODS

The study included 107 sequential samples from 10 HCV seroconversion commercial panels; 81 samples were in the preseroconversion phase, and 26 were collected after seroconversion. All samples were tested with HCV antigen-antibody assay and the two minipool (MP) NAT procedures that are routinely used in France (transcription-mediated amplification in pools of 8 and COBAS AmpliScreen HCV test [Roche Diagnostic] in pools of 24 donations).

RESULTS

From the 44 samples collected during window period that were MP-NAT-positive, 31 (70.5%) were also positive with the Monolisa HCV antigen-antibody assay. The mean delay in detecting HCV infection between these two methods was 5.1 days (range, 0-24 days). The Monolisa HCV antigen-antibody assay led to a reduction in the window period of 26.8 days (range, 0-72 days). All samples collected after seroconversion were detected with the HCV antigen-antibody assay. The specificity analyzed in 2503 consecutive blood donations was estimated at 99.88 percent.

CONCLUSION

This new developed assay presents an improvement for the detection of HCV infection, especially in the early phase of infection when antibodies are undetectable. Although less sensitive than NAT, this assay could be a suitable solution for blood screening in developing countries where NAT (or HCV core antigen-specific assay) is not affordable or its implementation is not feasible.

Residual risk of transfusion-transmitted human immunodeficiency virus, hepatitis C virus, and hepatitis B virus infections in Italy

BACKGROUND

Estimating the risk of transfusion-transmitted infections (TTIs) is essential for monitoring blood safety. The residual risk of TTI was estimated for nearly 90 percent of the blood supply in Italy.

STUDY DESIGN AND METHODS

Data were analyzed from 1,079,281 repeat donors, corresponding to 5,361,000 donations made in blood transfusion centers throughout Italy in the period 1999 through 2001. The residual risk of transfusion-transmitted human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B virus (HBV) infections was estimated with the incidence rate-window period model. The denominator for the incidence rate (i.e., the number of person-years at risk) was estimated on a sample of 5850 donors.

RESULTS

The risk of an infectious donation entering the blood supply, per 1 million donations, was 1.91 (probable range, 0.52-3.32) for HIV, 16.74 (9.57-24.01) for HCV, and 69.16 (43.12-102.70) for total HBV (adjusted for vaccination and hepatitis B surface antigen transience).

CONCLUSION

In Italy, the estimated residual risk of TTI is apparently low, particularly for HIV infection. Although the estimated risks are higher for HCV and HBV, the introduction of mandatory viral detection tests for HCV in 2002 should account for an 80 percent reduction in the HCV risk. Moreover, the ongoing HBV vaccination program will contribute to reducing the risk of transfusion-transmitted HBV.

Simultaneous detection of hepatitis C virus (HCV) core antigen and anti-HCV antibodies improves the early detection of HCV infection

To evaluate whether a new enzyme immunoassay developed for the simultaneous detection of hepatitis C virus (HCV) core antigen (Ag) and anti-HCV antibodies (anti-HCV Ab) (Monolisa HCV Ag/Ab ULTRA; Bio-Rad) could improve the early detection of HCV infection, we compared its sensitivity to that of anti-HCV, HCV core Ag, and HCV RNA assays. The populations studied included 12 blood donor samples positive for HCV RNA and HCV core Ag but negative for anti-HCV antibodies and 23 hemodialysis patients who developed anti-HCV Ab (seroconversion) during the follow-up. From these 23 individuals, 83 samples sequentially collected prior to seroconversion and 108 samples collected after seroconversion were tested. Six of 12 blood donations were positive by the HCV Ag/Ab assay. In the hemodialysis cohort, the 24 HCV RNA-negative samples were negative by the HCV Ag/Ab assay and 23 of the 59 HCV RNA-positive samples (39%) were positive. The HCV Ag/Ab assay detected HCV infection on average 21.6 days before the most sensitive antibody assay. The HCV Ag/Ab assay did not detect HCV infection as early as the HCV RNA assay (mean delay, 30.3 days) or HCV Ag assay (mean delays, 27.9, and 16.3 days by the HCV core Ag quantification assay and the HCV Ag blood screening assay, respectively). This new assay provides a notable improvement for the early detection of HCV infection during the so-called window period compared with anti-HCV Ab assays and could be a useful alternative to HCV RNA detection or HCV core Ag assays for diagnosis or blood screening when nucleic acid technologies or HCV core Ag detection are not implemented.

Design of novel conformational and genotype-specific antigens for improving sensitivity of immunoassays for hepatitis C virus-specific antibodies

The current commercially licensed enzyme-linked immunosorbent assays (ELISAs) for hepatitis C virus (HCV) mainly use recombinant proteins containing linear epitopes. There is evidence, however, that conformational epitopes of HCV are more immunoreactive. Thus, we have designed an HCV antibody assay that employs a conformational protein, NS3NS4a PI (with functional protease and helicase activities), and a linear fusion protein, multiple-epitope fusion antigen 7.1 (MEFA 7.1) or MEFA 7.2. We have shown that NS3NS4a PI detects early-seroconversion conformation-sensitive antibodies better than c33c antigen. The correct conformation of NS3NS4a PI also cross-reacts with different genotype samples better than the c33c antigen. MEFA 7.1 and MEFA 7.2 incorporate all the major immunodominant and genotype-specific epitopes of HCV core, E1, E2 hypervariable region 1 (HVR1), E2 HVR1-plus-HVR2 consensus, NS3, NS4, and NS5. Since MEFA 7.1 is degraded by the active NS3NS4a PI protease, we designed a second MEFA 7.2 construct in which the six protease cleavage sites found in MEFA 7.1 were eliminated by amino acid mutation. We demonstrate here that MEFA 7.2 remains intact in the presence of NS3NS4a PI and preserves the epitopes present in MEFA 7.1. Compared to currently licensed assays, an ELISA incorporating a combination of the two antigens NS3NS4a PI and MEFA 7.1 or 7.2 demonstrates better serotype sensitivity and detects seroconversion earlier in many commercially available panels. We believe that an assay using NS3NS4a PI and MEFA 7.1 or 7.2 may have the potential to replace current HCV immunoassays for better sensitivity.

Multicenter performance evaluation of a transcription-mediated amplification assay for screening of human immunodeficiency virus-1 RNA, hepatitis C virus RNA, and hepatitis B virus DNA in blood donations

BACKGROUND

The performance of the recently launched Procleix Ultrio (Chiron/Gen-Probe) human immunodeficiency virus-1 (HIV-1), hepatitis C virus (HCV), and hepatitis B virus (HBV) blood screening assay was evaluated in a European multicenter study.

STUDY DESIGN AND METHODS

Serial dilutions of reference materials were tested to determine the detection limits. Robustness and specificity were assessed by testing alternating high-load HCV RNA-positive and -negative samples, and 2912 test pools of eight donations. The added value of minipool and single-donation HBV nucleic acid testing protocols was compared to the currently used Prism (Abbott GmbH & Co. KG) hepatitis B surface antigen (HBsAg) and Auszyme (Abbott GmbH & Co. KG) dynamic HBsAg tests in 15 HBV seroconversion panels.

RESULTS

The 95 percent detection limits (and 95% confidence interval [CI]) on the WHO International Standards was 26 (16-58) IU per mL for HIV-1 RNA, 4.6 (3.7-6.5) IU per mL for HCV RNA, and 11 (7.3-22) IU per mL for HBV DNA. No cross-contamination was observed. Testing 2912 pools of eight donations revealed 16 initial reactive samples; 11 were confirmed. The specificity after initial testing and percentage of invalid results were 99.83 and 0.48 percent, respectively. The HBV window-period (WP) reductions relative to HBsAg seroconversion in Prism and Auszyme dynamic HBsAg were, respectively, 6 days (95% CI, 3-8) and 9 days (95% CI, 7-12) in 1:8 minipool (MP) testing.

CONCLUSION

The performance characteristics of Procleix Ultrio assay and the Procleix HIV-1 and HCV assay are comparable. The sensitivity for HIV-1 and HCV met the directives of the Paul-Ehrlich Institute and the FDA. The assay can reduce the WP for HBV by 6 days to 2 weeks when used in small MP (<1:8) or single-donation screening protocols.

Evaluation of five screening tests licensed in Argentina for detection of hepatitis C virus antibodies

This study was conducted to compare among the most recent generation of five screening tests licensed in Argentina, in order to evaluate which of the tests has the best sensitivity for detection of antibodies against hepatitis C virus (HCV). The tests analyzed were: Detect-HCV (3.0) Biochem ImmunoSystems, Canada; Hepatitis C EIA Wiener Lab., Argentina; Equipar HCV Ab, Italy; Murex HCV 4.0, UK and Serodia-HCV particles agglutination test, Japan. The results obtained showed high discrepancy between the different kits used and show that some of the tests assessed have a low sensitivity for anti-HCV detection in both chronic infections and early seroconversion, and indicate that among the commercially available kits in Argentina, Murex HCV 4.0 (UK) and Serodia-HCV particles agglutination test (Japan) have the best sensitivity for HCV screening. Although the sensitivity of the assays is the first parameter to be considered for blood screening, more studies should be carried out to assess the specificity of such assays.

Costs associated with blood transfusions in Sweden - the societal cost of autologous, allogeneic and perioperative RBC transfusion

Anaemia is characterised by an insufficient number of red blood cells (RBCs) and might occur for different reasons, e.g. surgical procedures are often with associated blood loss. Patients who suffer from anaemia have the option of treatment with blood transfusion or medical treatment. In this study, the societal cost, for the case of Sweden, of RBC transfusion using three different techniques, i.e. allogeneic, autologous and intraoperative transfusion, was estimated. The analysis was based on information from interviews with hospital staff at large Swedish hospitals and from published data. The average cost for a 2 units transfusion was found to be Swedish kronor (SEK) 6330 (702 Euro) for filtered allogeneic RBCs and SEK 5394 (598 Euro) for autologous RBCs for surgery patients. Transfusion reactions accounted for almost 35 per cent of the costs of allogeneic RBC transfusions. The administration cost was found to be much higher for autologous transfusions compared with allogeneic transfusions. The cost of intraoperative erythrocyte salvage was calculated to be SEK 2567 (285 Euro) per transfusion (>4 units).

Surveillance épidémiologique des donneurs de sang homologues et risque résiduel en France entre 2001 et 2003

The national surveillance of French blood donors is performed by the Institut de Veille Sanitaire and the National Reference Center for Hepatitis B and C in transfusion in collaboration with the Etablissement Français du Sang and the Army blood center. The main objectives of this surveillance are to evaluate trends in prevalence and incidence rates of blood-borne infections in the blood donor population, to identify routes of contamination and to assess residual risk. This exhaustive surveillance also contributes to evaluate the blood donor selection and the impact of measures taken to prevent infections in the general population. The analyse of the database of all blood donations obtained from 2001 to 2003 has shown that prevalence rates were stable in the study period (0.60 per 10(4) donors for HIV, 8.0 per 10(4) donors for HCV, 1.8 per 10(4) first-time donors for HBs Ag and 0.56 per 10(4) donors for HTLV), The incidence rate of HIV and HBV (1 per 10(5) person-years) was three-times higher than for HCV (0.35 per 10(5) person-years) and eleven times higher than for HTLV (0.09 per 10(5) person-years). At least, the residual risk of transfusion-transmitted viral infections is very low: 1/3,150,000 donations for HIV, 1/10,000,000 donations for HCV and 1/640,000 donations for HBV. The yield of Nucleic Acid Testing (NAT) is limited since only 2 donations for HIV and 3 for HCV which were negative for antibodies were discarded thank to the NAT.

Multicenter evaluation of a semiautomated, standardized assay for detection of hepatitis B virus DNA in blood donations

We evaluated the COBAS Ampliscreen hepatitis B virus (HBV) test using standards, seroconversion panels, consecutive donations, and samples from patients with abnormal alanine aminotransferase and chronic hepatitis C. Specificity was 100% and sensitivity was 20 IU/ml. In seroconversion panels, HBV DNA was detected up to 4 to 18 days before HBsAg, suggesting that this assay is useful in shortening the infectious window phase.

Biological qualification of blood units: considerations about the effects of sample's handling and storage on stability of nucleic acids

BACKGROUND

In transfusional setting introduction of nucleic amplification technique (NAT) for HBV-DNA, HCV-RNA and HIV-RNA in biological qualification of blood units suggest some problems. At first the opportunity to operate on mini-pool, at second the need to store the samples at +4 degrees C. The authors therefore have tried to estimate the impact of these conditions on the operativity of NAT testing in the transfusional setting.

METHODS

The following parameters has been estimated: distribution of viral-load in untreated subjects, stability of nucleic acids during storage at +4 degrees C, stability of nucleic acids after repeated cycles of freezing and defrosting, robustness of the test to the cross-contamination, definition of the detection-limit (95%). Quantitative tests has been performed by using the following kits: Cobas Amplicor HBV Monitor, Cobas Amplicor HCV Monitor, Cobas Amplicor HIV Monitor; the qualitative tests has been performed by using the following kits: Ampliscreen HBV, Ampliscreen HCV 2,0, Ampliscreen HIV 1,5 all supplied by Roche Molecular System (Brancburg, NJ).

RESULTS

Viral load in untreated subjects showed wide variation for HBV, HCV and HIV. HBV has been demonstrated much stable to the conservation +4 degrees C also until 168 h while for HCV and HIV a greater decrease of the viral-load was observed. For all and three virus the conservation to +4 degrees C until 72 h does not seem to involve meaningful fall in the viral-load. A remarkable reduction of the viral-load has been observed after five cycles of freezing and defrosting. All the tests showed a good robustness to cross-contamination. The detection-limit (95%) was 8 U/ml for HBV, 21 U/ml for HCV and 27 copy/ml for HIV.

CONCLUSIONS

Samples for NAT testing, can be stored until 72 h to +4 degrees C without appreciable lowering of the viral-load. Repeated cycles of changes of state should be avoided. The tests showed a good robustness to cross-contamination. NAT tests for biological qualification of blood units had a minimal sensibility around 50 (copy/unit/ml). In our experience the detection-limit (95%) was 21 U/ml for HCV, 27 copies/ml for HIV, 8 U/ml for HBV. The availability of NAT test for HBV-DNA, HCV-RNA e HIV-RNA, sensitive and reliable, together with epidemiological data, suggest the opportunity to place side by side, in the biological qualification of the blood units, to add the tests for HBV-DNA and HIV-RNA to the test for HCV-RNA mandatory by low, in Italy in the biological qualification of blood units.

Safety of the blood supply in Latin America

Appropriate selection of donors, use of sensitive screening tests, and the application of a mandatory quality assurance system are essential to maintain the safety of the blood supply. Laws, decrees, norms, and/or regulations covering most of these aspects of blood transfusion exist in 16 of the 17 countries in Latin America that are the subject of this review. In 17 countries, there is an information system that, although still incomplete (there are no official reports on adverse events and incidents), allows us to establish progress made on the status of the blood supply since 1993. Most advances originated in increased screening coverage for infectious diseases and better quality assurance. However, in 2001 to 2002, tainted blood may have caused infections in 12 of the 17 countries; no country reached the number of donors considered adequate, i.e., 5% of the population, to avoid blood shortages, or decreased significantly the number of blood banks, although larger blood banks are more efficient and take advantage of economies of scale. In those years, paid donors still existed in four countries and replacement donors made up >75% of the blood donors in another eight countries. In addition, countries did not report the number of voluntary donors who were repeat donors, i.e., the healthiest category. In spite of progress made, more improvements are needed.

Economics of pathogen inactivation technology for platelet concentrates in Japan

Residual risk of transmitting recognized and emerging blood-borne pathogens via blood transfusion in Japan persists despite advances in blood safety screening. The INTERCEPT Blood System (IBS) for platelets was developed to inactivate a broad spectrum of pathogens to reduce the risk of transfusion-transmitted infections. In this study we assessed the economic impact of the IBS on platelet transfusion costs. An economic analysis model was used to assess both net cost and cost-effectiveness of the IBS for the patient populations accounting for most of the platelet use in Japan. Pathogen exposure included viruses currently recognized to cause transfusion-transmitted infections and emerging pathogens of potential significance for transfusion-transmitted infections. Economic assessment of the full potential of the IBS revealed that only a small increase in net cost can be expected with implementation. The cost-effectiveness of the IBS for platelets is comparable with and potentially better than that of other blood safety interventions (eg, nucleic acid testing) and, in general, other recently implemented safety interventions (eg, chemical regulations and traffic safety measures) accepted as valuable in Japan. Thus a preventive approach using pathogen inactivation with the IBS may be considered a desirable strategy for improving the current safety of platelet transfusions in Japan.