International application of the incidence rate/window period model

Revised nucleic acid test window periods: Applications and limitations in organ donation practice

BACKGROUND

Nucleic acid test window periods for HIV, HCV, and HBV facilitate estimation of the residual risk of unexpected disease transmission and assist clinicians in determining the timeframe in which a recently acquired infection is at risk of nondetection.

OBJECTIVES

Firstly, to provide revised estimates of the NAT window periods based on a currently used triplex NAT assay. Secondly, to examine their validity in organ donation and transplantation practice.

METHOD

Estimates were based on the Procleix Ultrio Elite Assay (Grifols Diagnostic Solutions Inc. California, USA). The manufacturer's X50 and X95 limits of detection (LOD) were utilised. Viral doubling times of 0.85, 0.45, and 2.56 days and conversion factors for IU per ml to copies per mL of 0.6, 3.4, and 5 were assumed for HIV, HCV, and HBV respectively. Window periods were derived from the X50 and X95 LODs, based on a range of potential inoculum volumes.

RESULTS

Calculated X50 window periods were 5.1 (4.5-5.8), 2.7 (2.4-2.9), and 16.6 (14.2-19.1) days for HIV, HCV, and HBV respectively. Calculated X50 window periods, based on whole body plasma volume, were 11.8 (10.3-13.3), 6.2 (5.6-6.8) and 36.7 (31.3-42.1) days respectively.

CONCLUSION

X50 NAT window periods were significantly shorter for HBV and HCV and sit at the lower range of previously published estimates for HIV .  Current modeling assumptions may not account for all unexpected transmission events and may no longer be suitable for application to organ donation and transplantation.

Human immunodeficiency virus, hepatitis C virus and hepatitis B virus incidence in blood donors from 2000 to 2020 in France: Trends and lessons from haemovigilance surveillance

BACKGROUND AND OBJECTIVES

Data from 21 years (2000-2020) of haemovigilance were used to assess human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) incidence rates in repeat blood donors and the occurrence of transfusion-transmitted (TT) viral infections.

MATERIALS AND METHODS

Blood donors who converted for HIV, HCV or HBV markers within serial three-year analysis periods were included. Epidemiological and virological data were retrieved from the national epidemiological donor database and were supplemented with information on blood components and the infection status of recipients of the previous negative donation (D.N-1) of donors who seroconverted.

RESULTS

Incidence rates declined from 1.27 to 0.35/100,000 person-years for HIV, from 0.59 to 0.19 for HCV and from 1.66 to 0.18 for HBV. Risk factors and lookback for 232 HIV, 90 HCV and 74 HBV seroconversions were investigated. The main risk factor identified at post-donation interview was having sex with men (47.8% of males) for HIV and a sexual risk for HCV (30.6%) and HBV (37.1%). The viral loads and sequences were retrospectively tested in 191 HIV, 74 HCV and 62 HBV D.N-1 archived samples. Six (five HBV and one HIV-1) were positive all low viral loads. Two recipients were infected by red blood cells from two HBV seroconverting donors before the introduction of HBV-nucleic acid testing.

CONCLUSION

HIV, HCV and HBV incidence rates in blood donors declined over the two past decades in France. There is a very small risk of a blood component that tests negative entering the blood supply resulting in TT infections, especially after introduction of molecular assays in donor screening.

Increasing horizontal transmission of human T-cell leukemia virus type 1 in adolescents and young adults in Japan

BACKGROUND

Human T-cell leukemia virus type 1 (HTLV-1) is a causative agent of the life-threatening diseases, adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy. Following implementation of antenatal screening in Japan, novel transmission of HTLV-1 in adolescent and adult generations is expected to replace vertical transmission as the main route for transmission.

OBJECTIVES

To obtain the current status of HTLV-1 horizontal infection and to assess the fluctuation of transmission occurring among adolescents and adults in Japan.

STUDY DESIGN

We followed-up 5,017,916 eligible repeat blood donors for 8 years from 2013 to 2021. We evaluated HTLV-1 transmission rate by age group (16-69 years-old), and calculated the total number of novel transmissions in Japan using demographic statistics published by the government of Japan.

RESULTS

We identified 457 seroconverters (men, 203; women, 254) in a total of 19,244,604 person-years during the study period. The number of seroconversions per 100,000 person-years was 1.54 for men and 4.21 for women. An increase in the number of novel infections was observed in both sexes in adolescent and young adult generations despite the health bias of blood donors.

CONCLUSIONS

We estimate that more than 2,800 new HTLV-1 infections occur annually in Japan. It is a serious concern that without immediate measures against new HTLV-1 infections, such as guideline formulation, an inclusion of HTLV as routine screening in sexual health services, an information campaign, and surveillance of the general population, novel HTLV-1 infection could continue to increase in Japan and be a source of global transmission.

Evolution of Blood Safety in Switzerland over the Last 25 Years for HIV, HCV, HBV and Treponema pallidum

During the last few decades, efforts to increase the safety of blood and blood products have mainly focused on preventing the viral infections HCV, HIV, HBV and Treponema pallidum. The evolution of these approaches and the achieved increase in safety is shown for the last 25 years in Switzerland. In detail, the prevalences and incidences of the infection disease and the theoretical estimated residual risks (RR) of these blood-borne infections are presented. Prevalences, incidences and, in particular, the RR have decreased considerably over the last 25 years. This was achieved primarily by the adoption of strict criteria for the selection of blood donors, refined questionnaires, the introduction of increasingly sensitive serological screening tests and the implementation of nucleic acid testing (NAT) for these blood-borne pathogens. These NAT assays have significantly shortened the window period between infection and the first detection of the infectious agent in the blood of an infected individual. A form of "real life" comparison or confirmation is provided by the reported lookback procedures (LBP) and the haemovigilance data of the Swiss competent authority, Swissmedic. These data are in agreement, and thus support the very low prevalences, incidences and RR.

A rapid variant-tolerant reverse transcription loop-mediated isothermal amplification assay for the point of care detection of HIV-1

Human immunodeficiency virus (HIV) continues to be a major burden on public health globally with on-going increases in the number of new infections each year. Rapid and sensitive point-of-care tests allow timely interventions and are essential to control the spread of the disease. However the highly variable nature of the virus, resulting in the evolution of many subtypes and inter-subtype recombinants, poses important challenges for its diagnosis. Here we describe a variant-tolerant reverse-transcription RT-LAMP amplification of the virus's INT gene, providing a simple to use, rapid (<30 min) in vitro point-of-care diagnostic test with a limit of detection <18 copies/reaction. The assay was first validated in clinical studies of patient samples, using both established RT-LAMP and RT-qPCR assays for reference, with results showing that this new variant-tolerant HIV-1 RT-LAMP diagnostic test is highly sensitive without compromising its high specificity for HIV-1 subtypes. The diagnostic test was subsequently configured within an easy-to-read paper microfluidic lateral flow test and was validated clinically using patient samples, demonstrating its future potential for use in timely, effective, low cost HIV diagnostics in global regions where healthcare resources may be limited.

An international comparison of HIV prevalence and incidence in blood donors and general population: a BEST Collaborative study

BACKGROUND AND OBJECTIVES

Efficiency in mitigating HIV transmission risk by transfusion may vary internationally. We compared HIV prevalence and incidence in blood donors across different jurisdictions in relation to those rates in the general population and differences in deferral practices.

MATERIALS AND METHODS

Data from 2007 to 2016 were collected in Australia, Brazil (São Paulo), Canada, England, France, Italy, Ireland, Japan, the Netherlands, New Zealand, Norway, Spain (Basque Country), USA (Vitalant) and Wales. For each country/region, the number of HIV antibody-positive donations and nucleic acid testing (NAT)-only-positive donations was broken down according to first-time or repeat donor status, along with the relevant denominators.

RESULTS

There is a modest correlation between HIV prevalence among first-time donors and HIV prevalence in the general population. However, rates of HIV-positive donations in repeat donors, a proxy for incidence, do not correlate with incidence rates in the general population. Rates in donors from Italy and Basque Country, where deferral criteria for men having sex with men are less stringent, are higher compared with most other jurisdictions. Rates of NAT-only-positive donations are extremely low and do not differ significantly after adjustment for multiple comparisons.

CONCLUSION

Donor HIV rates are only weakly associated with those observed in the general population. Countries with less stringent deferral criteria have higher HIV rates in their donor population, but the rates remain very low.

Estimation of the window period of human T-cell leukemia virus type 1 and 2 tests by a lookback study of seroconverters among Japanese voluntary blood donors

BACKGROUND

Japan is endemic for human T-cell leukemia virus type 1 (HTLV-1), and the horizontal transmission of HTLV-1 is often reported. However, the window period (WP) for serologic or molecular screening is unclear.

STUDY DESIGN AND METHODS

Results for anti-HTLV-1 screening and confirmatory tests obtained from 648 591 repeated blood donors in the Kyushu district, one of the most endemic areas of HTLV-1 in the world, were evaluated. A lookback study was conducted for seroconverters.

RESULTS

During 2012 to 2019, 436 seroconverters (155 men, 281women) were identified with use of a screening chemiluminescence enzyme-immunoassay (CLEIA) and multiple confirmatory tests. Because the period between the latest seronegative donation and seroconversion was highly variable (2.1-276.7 months), 19 cases that seroconverted within 6 months were subjected to the analysis. The WP of the particle agglutination assay and CLEIA was estimated to be 2.2 ± 0.6 and 2.6 ± 1.7 months, respectively. The WP of the indirect immunofluorescence assay was 4.8 ± 6.5 months. Although the WP of western blotting was estimated to be 6.3 ± 8.7 months, four cases were still indeterminate through the study period. Chemiluminescence and line immunoassays, the current screening and confirmatory tests used in the Japanese blood program, showed the shortest WP of 2.2 ± 0.6 months. The WP of real-time polymerase chain reaction for HTLV-1 was estimated to be 4.1 ± 7.8 months.

CONCLUSIONS

The WP in commercially available testing systems for HTLV-1/2 was determined for natural infection among repeated blood donors. Considering the HTLV-1 WP will help increase transfusion safety and facilitate the accurate diagnosis of HTLV-1 infection.

HIV incidence in South African blood donors from 2012 to 2016: a comparison of estimation methods

BACKGROUND

Measuring incidence is important for monitoring and maintaining the safety of the blood supply. Blood collected from repeat-donors has provided the opportunity to follow blood donors over time and has been used to estimate the incidence of viral infections. These incidence estimates have been extrapolated to first-time donors using the ratio of NAT yield cases in first-time versus repeat-donors. We describe a model to estimate incidence in first-time donors using the limiting antigen (LAg) avidity assay and compare its results with those from established models.

METHODS

HIV-positive first-time donations were tested for recency using the LAg assay. Three models were compared; incidence estimated for (1) first-time donors using LAg avidity, (2) first-time and repeat-donors separately using the NAT yield window period (WP) model and (3) repeat-donors using the incidence/WP model.

RESULTS

HIV incidence in first-time donors was estimated at 3·32 (CI 3·11, 3·55) and 3·81 (CI 3·07, 4·73) per 1000 PY using the LAg assay and NAT yield WP models, respectively. Incidence in repeat-donors was between 2·0- and 2·5-fold lower than in first-time donors estimated at 1·56 (CI 1·37, 1·77) and 1·94 (CI 1·86-2·01) per 1000 PY using the NAT yield/WP and incidence/WP models, respectively.

CONCLUSION

Testing HIV-positive donations using the LAg assay provides a reliable method to estimate incidence in first-time donors for countries that collect the majority of blood from first-time donors and do not screen with NAT.

HIV prevalence and incidence estimates among blood donors in five regions in China

BACKGROUND

Previous data, although scant, indicated that the incidence of HIV in China has increased over the past decade. There is a growing concern about the impact of the HIV epidemic on blood safety.

METHODS AND MATERIALS

We used donation data from five geographically-disperse blood centers in 2013-2016 participating in the Recipient Epidemiology and Donor Evaluation Study-III (REDS-III) China program to estimate HIV prevalence and incidence among blood donors. Multivariable logistic regression model was used to examine factors associated with HIV infection in Chinese blood donors.

RESULTS

The overall HIV prevalence among first-time donors from 2013 through 2016 was 68.04 per 100,000 donors (95% CI 61.68-74.40). The HIV incidence rate was estimated to be 37.93 per 100,000 person-years (95% CI 30.62-46.97) among first-time donors and 20.55 per 100,000 person-years (95% CI 16.95-24.91) among repeat donors. There was substantial variation in HIV prevalence and incidence rates across blood centers. Multivariable logistic regression results showed that among first-time donors, being male, older than 25 years, minority ethnicity, less than college education, and certain occupations (commercial services, factory workers, retired, unemployed, or self-employed) were associated with positive HIV confirmatory testing results.

CONCLUSION

HIV prevalence and incidence among blood donors remain low in the selected five regions in China; however, an increasing trend is observed at some blood centers. It is important to monitor HIV epidemiology in Chinese blood donors on a continuous basis, especially among populations and regions of higher risk.

Prevalence, incidence and residual risk of transfusion-transmitted hepatitis B virus infection in Italy from 2009 to 2018

BACKGROUND

In Italy, the use of nucleic acid testing for hepatitis B virus (HBV) in donor screening has allowed the detection of infections in the window phase, as well as the presence of occult infections which could potentially be transmitted. The aim of this study was to analyse the trends of epidemiological data focused on HBV infection in blood donors and to estimate the residual risk of transmitting HBV from both the window phase and occult infection over a 10-year period in Italy.

MATERIALS AND METHODS

Data were obtained from the Italian Haemovigilance System which includes the results of screening tests for transfusion transmissible infections. During the period of this survey (2009-2018), the molecular methods used for HBV screening were transcription-mediated amplification and polymerase chain reaction tests. Prevalence and incidence were calculated. The residual risk was estimated by applying the incidence-window period model for acute cases and a more recently reported model for estimating the risk due to occult infections.

RESULTS

A total of 17,424,535 blood donors and 30,842,794 donations were tested for HBV. Altogether, 6,250 donors tested positive for HBV markers: 4,782 (175.6×10⁵) were first time donors and 1,468 (10.0×10⁵) were repeat donors. The prevalence of HBV markers in first time donors was 275.9×10⁵ in 2009, declining to 143.6×10⁵ in 2018. The incidence of new infections was 3.37×10⁵ in 2009 and 2.17×10⁵ in 2018. The overall residual risk for HBV amounted to 1 in 2,566,854 donations calculated as the sum of risks of both acute infections in the window period (1 in 5,835,306 donations) and occult infections (1 in 4,582,270 blood units).

DISCUSSION

In Italy, the residual risk of transfusing a blood unit infected with HBV, both from window phase and occult infections, is currently very low, amounting to levels that can be considered tolerable.

Prevention of transfusion-transmitted infections

Since the 1970s, introduction of serological assays targeting virus-specific antibodies and antigens has been effective in identifying blood donations infected with the classic transfusion-transmitted infectious agents (TTIs; hepatitis B virus [HBV], HIV, human T-cell lymphotropic virus types I and II, hepatitis C virus [HCV]). Subsequently, progressive implementation of nucleic acid-amplification technology (NAT) screening for HIV, HCV, and HBV has reduced the residual risk of infectious-window-period donations, such that per unit risks are <1 in 1 000 000 in the United States, other high-income countries, and in high-incidence regions performing NAT. NAT screening has emerged as the preferred option for detection of newer TTIs including West Nile virus, Zika virus (ZIKV), and Babesia microti Although there is continual need to monitor current risks due to established TTI, ongoing challenges in blood safety relate primarily to surveillance for emerging agents coupled with development of rapid response mechanisms when such agents are identified. Recent progress in development and implementation of pathogen-reduction technologies (PRTs) provide the opportunity for proactive rather than reactive response to blood-safety threats. Risk-based decision-making tools and cost-effectiveness models have proved useful to quantify infectious risks and place new interventions in context. However, as evidenced by the 2015 to 2017 ZIKV pandemic, a level of tolerable risk has yet to be defined in such a way that conflicting factors (eg, theoretical recipient risk, blood availability, cost, and commercial interests) can be reconciled. A unified approach to TTIs is needed, whereby novel tests and PRTs replace, rather than add to, existing interventions, thereby ameliorating cost and logistical burden to blood centers and hospitals.

[Transfusion-transmitted Infections: How Useful and Costly is Testing for new Infectious Disease Pathogens?]

Zusammenfassung. Bis Anfang der 1990er Jahre waren Blutprodukte nicht selten mit HIV oder HCV kontaminiert, was zu vielen transfusionsbedingten Infektionen führte. Seither wurde die Sicherheit von Blutprodukten in Bezug auf die Infektionsübertragung mit aufwendigen Massnahmen stark erhöht. Aktuell stehen sogenannte (re)emerging-Infektionserreger im Fokus, beispielsweise West Nile-, Zika- und Hepatitis-E-Viren. Ob und wie sich neue Massnahmen, die eine Übertragung dieser Viren verhindern sollen, kosteneffizient einführen lassen, muss mit klar definierten Vorgaben abgeklärt werden. Der entsprechende Entscheid muss gemeinsam mit den involvierten Stakeholdern und auch aufgrund von Kosten-Nutzen-Überlegungen getroffen werden. Grundsätzlich gilt, dass es eine 100-prozentige Sicherheit in Bezug auf die Übertragung von Infektionserregern mit Blutprodukten nie geben wird.

HCV RNA Testing of Plasma Samples from Cornea Donors: Suitability of Plasma Samples Stored at 4 °C for up to 8 Days

BACKGROUND

The HCV RNA testing of potential cornea donors frequently relies on blood samples stored pre mortem. The recommended storage time of maximum 72 h frequently excludes a significant fraction of donors.

METHODS

The influence of storage time of EDTA plasma samples at 4 °C on the viral load measured with the Roche HCV Quantitative Test vs. 2.0 was evaluated for 43 samples from HCV-positive individuals.

RESULTS

The mean reduction of the viral load after 4 °C storage for 6-8 days was 0.46 log₁₀ IU/ml (range +0.17 to -1.66 log₁₀ IU/ml). After 1-3 days a mean loss of 0.19 log₁₀ IU/ml (range +0.30 to -1.41 log₁₀ IU/ml) and after 3-5 days of 0.32 log₁₀ IU/ml (range +0.36 to -1.81 log₁₀ IU/ml) was observed. In 23.3% of samples, a viral load reduction ≥ 1 log₁₀ IU/ml (1.0-1.81 log₁₀ IU/ml) was found after prolonged storage (5-8 days). In none of the samples did the HCV load fall below the detection limit.

CONCLUSION

Plasma storage for up to 8 days can quantitatively reduce the HCV RNA load, yet has no influence on the reliability of a qualitative HCV RNA detection by this ultrasensitive test to determine the HCV status of serologically negative cornea donors.

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.

Incidence of human T-lymphotropic virus 1 infection in adolescent and adult blood donors in Japan: a nationwide retrospective cohort analysis

BACKGROUND

Human T-lymphotropic virus 1 (HTLV-1) infection has an especially high prevalence in Japan. Transmission has been confirmed in infancy through breastfeeding; however, little is known about the epidemiological aspects of new HTLV-1 infections later in life. We aimed to estimate the nationwide annual number of new HTLV-1 infections among adolescents and adults in Japan.

METHODS

In this retrospective cohort analysis, we assessed new HTLV-1 infections of repeat blood donors aged 16-69 years between Jan 1, 2005, and Dec 31, 2006, in the Japanese Red Cross Blood Centres database. We used results of antibody tests done in repeat blood samples collected until Dec 31, 2011, to assess the number who seroconverted to HTLV-1. We calculated the incidence density by dividing the number of seroconverters by the number of person-years of follow-up, and then extrapolated densities to regional populations to estimate the annual number of new HTLV-1 infections.

FINDINGS

We included 3 375 821 HTLV-1-seronegative blood donors (2 100 915 men and 1 274 906 women). Within a median follow-up of 4·5 years (IQR 2·3-5·8), 532 people (204 men and 328 women) had seroconverted. The incidence density was significantly higher in women (6·88 per 100 000 person-years; 95% CI 6·17-7·66) than in men (2·29 per 100 000 person-years; 95% CI 1·99-2·62; p<0·0001). The estimated annual number of new HTLV-1 infections was 4190 (95% CI 4064-4318) with 975 (914-1038) infections in men and 3215 (3104-3328) in women.

INTERPRETATION

New HTLV-1 infections in adolescents and adults are an important public health concern in Japan and preventive strategies are needed to reduce new transmission.

FUNDING

Ministry of Health, Labour, and Welfare of Japan; Japan Agency for Medical Research and Development.

Impact of using different blood donor subpopulations and models on the estimation of transfusion transmission residual risk of human immunodeficiency virus, hepatitis B virus, and hepatitis C virus in Zimbabwe

BACKGROUND

Various models for estimating the residual risk (RR) of transmission of infections by blood transfusion have been published mainly based on data from high-income countries. However, to obtain the data required for such an assessment remains challenging for most developing settings. The National Blood Service Zimbabwe (NBSZ) adapted a published incidence-window period (IWP) model, which has less demanding data requirements. In this study we assess the impact of various definitions of blood donor subpopulations and models on RR estimates. We compared the outcomes of two published models and an adapted NBSZ model.

STUDY DESIGN AND METHODS

The Schreiber IWP model (Model 1), an amended version (Model 2), and an adapted NBSZ model (Model 3) were applied. Variably the three models include prevalence, incidence, preseroconversion intervals, mean lifetime risk, and person-years at risk. Annual mean RR estimates and 95% confidence intervals for each of the three models for human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) were determined using NBSZ blood donor data from 2002 through 2011.

RESULTS

The annual mean RR estimates for Models 1 through 3 were 1 in 6542, 5805, and 6418, respectively for HIV; 1 in 1978, 2027, and 1628 for HBV; and 1 in 9588, 15,126, and 7750, for HCV.

CONCLUSIONS

The adapted NBSZ model provided comparable results to the published methods and these highlight the high occurrence of HBV in Zimbabwe. The adapted NBSZ model could be used as an alternative to estimate RRs when in settings where two repeat donations are not available.

Namibia's transition from whole blood-derived pooled platelets to single-donor apheresis platelet collections

BACKGROUND

Few African countries separate blood donations into components; however, demand for platelets (PLTs) is increasing as regional capacity to treat causes of thrombocytopenia, including chemotherapy, increases. Namibia introduced single-donor apheresis PLT collections in 2007 to increase PLT availability while reducing exposure to multiple donors via pooling. This study describes the impact this transition had on PLT availability and safety in Namibia.

STUDY DESIGN AND METHODS

Annual national blood collections and PLT units issued data were extracted from a database maintained by the Blood Transfusion Service of Namibia (NAMBTS). Production costs and unit prices were analyzed.

RESULTS

In 2006, NAMBTS issued 771 single and pooled PLT doses from 3054 whole blood (WB) donations (drawn from 18,422 WB donations). In 2007, NAMBTS issued 486 single and pooled PLT doses from 1477 WB donations (drawn from 18,309 WB donations) and 131 single-donor PLT doses. By 2011, NAMBTS issued 837 single-donor PLT doses per year, 99.1% of all PLT units. Of 5761 WB donations from which PLTs were made in 2006 to 2011, a total of 20 (0.35%) were from donors with confirmed test results for human immunodeficiency virus or other transfusion-transmissible infections (TTIs). Of 2315 single-donor apheresis donations between 2007 and 2011, none of the 663 donors had a confirmed positive result for any pathogen. As apheresis replaced WB-derived PLTs, apheresis production costs dropped by a mean of 8.2% per year, while pooled PLT costs increased by an annual mean of 21.5%. Unit prices paid for apheresis- and WB-derived PLTs increased by 9 and 7.4% per year on average, respectively.

CONCLUSION

Namibia's PLT transition shows that collections from repeat apheresis donors can reduce TTI risk and production costs.

Nucleic acid testing for blood banks: an experience from a tertiary care centre in New Delhi, India

INTRODUCTION

Blood safety is a challenging task in India; with a population of around 1.23 billion and a high prevalence rate of HIV (0.29%), HBV (2-8%) and HCV (≈ 2%) in general population. Nucleic acid testing (NAT) in blood donor screening has been implemented in many developed countries to reduce the risk of transfusion-transmitted viral infections (TTIs). NAT shortens this window period, thereby offering blood centers a much higher sensitivity for detecting viral infections.

MATERIALS AND METHODS

Routine ID-NAT for HIV-1, HCV and HBV was started from June 2010 at AIIMS blood bank by the Procleix® Ultrio® Assay (Novartis Diagnostics, USA) a multiplex NAT, which allows the simultaneous detection of HIV-1, HCV, and HBV in a single tube. During the period of 27 months from June 2010 to August 2012, around 73,898 samples were tested for all the three viruses using both ELISA (by Genscreen Ultra HIV Ag-Ab(BIO-RAD), Hepanostika HCV Ultra & HBsAg Ultra(Biomerieux) and Nucleic acid testing. The comparative results of both the assays are being presented here in this study.

RESULTS

Out of 73,898 samples, 1104 samples (1.49%) were reactive by NAT. out of these 1104 samples, 73 were reactive for HIV-1 (0.09%), 186 were reactive for HCV only (0.25%), 779 (1.05%) were reactive for HBV only, and around 66 (0.08%) were HBV-HCV co-infections. There was one HIV, 37 HCV, 73 HBV and 10 HBV-HCV co-infection cases that were not detected by serology but reactive on NAT testing, with a combined yield of 1 in 610 donations (total 121 NAT yields).

CONCLUSION

NAT could detect HIV, HBV and HCV cases in blood donor samples that were undetected by serological tests. NAT can interdict a large number of infected unit transfusions and thus help in providing safe blood to the patients.

Intrafamilial transmission of hepatitis C infection in Egyptian multitransfused thalassemia patients

OBJECTIVE

Detecting the current prevalence of hepatitis C virus (HCV) among Egyptian multitransfused thalassemic patients and evaluating the risk of its transmission within their family members.

METHODS

Multitransfused Egyptian thalassemia patients (n = 137) were tested for HCV infection. Household contacts of positive members were compared with household contacts of HCV-negative patients. Antibodies to HCV were detected by enzyme immunoassay. Antibody-positive cases were retested for viral load using reverse transcriptase polymerase chain reaction. HCV genotyping was performed on positive samples of the patients and the positive household contacts.

RESULTS

In all, 34.4% of patients (n = 47) were positive for HCV antibodies and RNA. The study of 24 families of HCV-positive patients showed 14 affected family members (19.2%). In 27 families of HCV-negative patients, four family members were affected (4.9%). HCV genotyping of seven families was similar in both patients and their family members.

CONCLUSION

Our results support the role of intrafamilial transmission in the spread of HCV.

Residual Risk of Hepatitis-B-Infected Blood Donations: Estimation Methods and Perspectives

Despite a considerable reduction of the risk of HBV-infected blood donation entering blood supply (residual risk) due to improved screening by HBV NAT in the developed countries, the bulk of the people with HBV living in the developing countries still needs to be screened by serologic tests such as HBsAg and anti-HBc. Many of these countries lack resources for implementing NAT and are likely to remain so in the next decade or longer, thus depending on the HBV residual risk monitoring based on serologic testing and corresponding estimation methods. This paper reviews main HBV residual risk findings worldwide and the methods based on serology used for their calculation with repeat donors, as well as their extension to the first-time donors. Two artificial datasets with high (4.36%) and low (0.48%) HBV prevalence were generated to test the performance of five methods: the original incidence/window-period model based solely on HBsAg, its modification by Soldan in 2003, the Müller-Breitkreutz model, the HBsAg yield model, and its extension to include anti-HBc seroconversions within a year. The last model was closest to the true values of residual risk and had smallest variation of the estimates in both high and low prevalence data. It may be used for residual risk evaluation in relatively small samples, such as regional blood banks data.

Prevalence, incidence, and residual risks for transfusion-transmitted human immunodeficiency virus Types 1 and 2 infection among Chinese blood donors

BACKGROUND

There are little data on human immunodeficiency virus (HIV) prevalence, incidence, or residual risks for transfusion-transmitted HIV infection among Chinese blood donors.

STUDY DESIGN AND METHODS

Donations from five Chinese blood centers in 2008 to 2010 were screened using two rounds of enzyme-linked immunosorbent assay for anti-HIV-1/2. A reactive result in either or both rounds led to Western blot confirmatory testing. HIV prevalence among first-time donors and incidence among repeat donors were examined. Weighted multivariable logistic regression analysis examined correlates of HIV confirmatory status among first-time donors. Residual risks were evaluated based on incidence among repeat donors.

RESULTS

Among 821,320 donations, 40% came from repeat donors. A total of 1837 (0.34%) first-time and 577 (0.17%) repeat donations screened reactive, among which 1310 and 419 were tested by Western blot. A total of 233 (17.7%) first-time and 44 (10.5%) repeat donations were confirmed positive. Prevalence was 66 infections per 100,000 (95% confidence interval [CI], 59-74) first-time donors. Incidence was 9 of 100,000 (95% CI, 7-12) person-years among repeat donors. Multivariable logistic regression analysis indicates that first-time donors 26 to 45 years old were 1.6 to 1.8 times likely to be HIV positive than those 25 years and younger. Donors with some college or above education were less likely to be HIV positive than those with middle school education, odds ratios (ORs) ranging from 0.35 to 0.60. Minorities were 1.5 times likely to be HIV positive than Han majority donors (OR, 1.6; 95% CI, 1.2-2.1). HIV residual risk was 5.4 (95% CI, 1.2-12.5) infections per million whole blood donations.

CONCLUSION

Despite the declining HIV epidemic in China, estimated residual risks for transfusion-transmitted HIV infection are still high.

The National Heart, Lung, and Blood Institute retrovirus epidemiology donor studies (Retrovirus Epidemiology Donor Study and Retrovirus Epidemiology Donor Study-II): twenty years of research to advance blood product safety and availability

The Retrovirus Epidemiology Donor Study (REDS), conducted from 1989 to 2001, and the REDS-II, conducted from 2004 to 2012, were National Heart, Lung, and Blood Institute-funded, multicenter programs focused on improving blood safety and availability in the United States. The REDS-II also included international study sites in Brazil and China. The 3 major research domains of REDS/REDS-II have been infectious disease risk evaluation, blood donation availability, and blood donor characterization. Both programs have made significant contributions to transfusion medicine research methodology by the use of mathematical modeling, large-scale donor surveys, innovative methods of repository sample storage, and establishing an infrastructure that responded to potential emerging blood safety threats such as xenotropic murine leukemia virus-related virus. Blood safety studies have included protocols evaluating epidemiologic and/or laboratory aspects of human immunodeficiency virus, human T-lymphotropic virus 1/2, hepatitis C virus, hepatitis B virus, West Nile virus, cytomegalovirus, human herpesvirus 8, parvovirus B19, malaria, Creutzfeldt-Jakob disease, influenza, and Trypanosoma cruzi infections. Other analyses have characterized blood donor demographics, motivations to donate, factors influencing donor return, behavioral risk factors, donors' perception of the blood donation screening process, and aspects of donor deferral. In REDS-II, 2 large-scale blood donor protocols examined iron deficiency in donors and the prevalence of leukocyte antibodies. This review describes the major study results from over 150 peer-reviewed articles published by these 2 REDS programs. In 2011, a new 7-year program, the Recipient Epidemiology and Donor Evaluation Study-III, was launched. The Recipient Epidemiology and Donor Evaluation Study-III expands beyond donor-based research to include studies of blood transfusion recipients in the hospital setting and adds a third country, South Africa, to the international program.

Risk factors of hepatitis C infection among Egyptian blood donors

BACKGROUND

Surveillance of infectious disease markers in the blood donor population is important in recognizing trends in prevalence and incidence of transfusion related infections in asymptomatic volunteer blood donors.

SUBJECTS AND METHODS

It was a cross sectional study. Samples were collected from volunteer blood donors and questionnaire was designed to collect the risk factors data. The prevalence of hepatitis C antibodies among 1,000 apparently healthy blood donors were determined.

OBJECTIVE

To estimate the prevalence of virus C hepatic infection and to illustrate the various socio-economic, behavioural and medical factors related to infection with Hepatitis C (HCV) among apparently healthy individuals. It contributed to analysis of the particularities of Egyptian blood donors and helped to better understand the challenges and solutions of blood safety.

RESULTS

The prevalence of HCV was 16.8%. There was an association of positive anti-HCV test with socio-demographic, medical and behavioural risk factors.

CONCLUSION

This study provided comprehensive and reliable information on the possible risk factors affecting spread of Hepatitis C in the area.

Infectivity in chimpanzees (Pan troglodytes) of plasma collected before HCV RNA detectability by FDA-licensed assays: implications for transfusion safety and HCV infection outcomes

Serial plasma aliquots (50 mL) obtained from 10 commercial donors who converted from hepatitis C virus (HCV) RNA negative to positive were transfused into 2 chimpanzees to assess infectivity during early HCV infection. Plasma, obtained 4 days before HCV RNA detectability by licensed assays, transmitted HCV infection to chimpanzee X355. The infectious PCR-negative plasma was subsequently shown to be positive in 2 of 23 replicates using a sensitive transcription-mediated amplification (TMA) assay, and estimated to contain 1.2 HCV RNA copies/mL (60 copies/50 mL transfused). Plasma units obtained up to 8 weeks earlier were not infectious in a second susceptible chimp, even when from donors with low-level, intermittent HCV RNA detection. Chimp x355 developed acute viremia with subsequent seroconversion, but cleared both virus and Ab in 17 weeks. When rechallenged 38 months later with 6000 RNA copies/mL from the same donor, X355 was transiently reinfected and again rapidly lost all HCV markers. We conclude that: (1) transfusions can transmit HCV infection before RNA detection, but the interval of test-negative infectivity is very brief; (2) early "blips" of HCV RNA appear noninfectious and can be ignored when calculating residual transfusion risk; and (3) markers of HCV infection can be lost rapidly after exposure to low-dose inocula.

Transfusion Transmitted Infections in Armed Forces: Prevalence and Trends

BACKGROUND

This study presents data on the prevalence rate of infectious markers among voluntary and replacement donors in the blood transfusion service in Armed Forces from 2000 to 2004.

METHODS

39,646 units of blood were collected from donors during the period from 2000 to 2004. All the samples were screened for hepatitis B surface antigen (HBsAg), human immunodeficiency virus (HIV) 1&2, hepatitis C virus (HCV), and by venereal disease research laboratory test (VDRL).

RESULTS

24,527 (61.9%) were voluntary donations and 15,119 (38.1%) replacement donations. Prevalence of HBsAg had decreased, amongst voluntary donors from 1.67% to 0.77% but the positivity rate has not showed significant change. Seropositivity of HIV had decreased both in voluntary and replacement donors to 0.22% and 0.86% respectively. The seropositivity for anti-HCV showed steady decrease amongst voluntary donors from 0.46% to 0.20% in 2004, but in replacement donors, there was an increase in reactivity rate from 0.43% to 0.65%.

CONCLUSION

The increased seropositivity for HCV, HIV and HBsAg could be decreased by introduction of nucleic acid amplification testing (NAT) in minipools for HCV and HIV and introduction of anti-HBcAg (IgM) for hepatitis B virus (HBV) infection. But this may not be possible in near future in developing countries due to financial constraints. At present implementation of strict donor criteria and with use of sensitive laboratory screening tests it is possible to reduce the incidence of transfusion transmitted infections (TTI) in Indian scenario.

Reducing the risk of hepatitis B virus transfusion-transmitted infection

Before 1970, approximately 6% of multi-transfused recipients acquired a transfusion-transmitted Hepatitis B virus (HBV) infection. The safety improvements since then have been tremendous. From a level of a few infections per 1000 donations, the risk today, depending on the screening algorithm and additional measurements performed, has decreased to around 1:500,000 to 1:1,000,000, an improvement greater than 1000-fold compared to 50 years ago. This enormous gain in safety has been achieved through many factors, including development of increasingly more sensitive Hepatitis B antigen (HBsAg) assays; the adoption in some countries of hepatitis B core antibody (anti-HBc) screening; an improved donor selection procedure; HBV vaccination programs; and finally the introduction of HBV nucleic acid testing (NAT). Because there is a tendency in transfusion medicine to add one safety measure on top of another to approach the ultimate goal of zero risks, costs become increasingly a matter of debate. It is obvious that any new measure in addition to existing methods or measures will have very poor cost effectiveness. Therefore each country needs to perform its own calculation based on the country’s own epidemiology, resources, political and public awareness of the risks, in order to choose the correct and most cost-efficient measures. Ideally, each country would make decisions regarding implementation of additional blood safety measures in the context of both the perceived benefit and the allocation of overall health care resources.

Comparison of epidemiological methods for estimation of hepatitis B incidence and residual risk for blood donors in southern Brazil

Background and Objective. The objective of this work was to compare three methods for estimating hepatitis B virus (HBV) incidence and residual risk. Methods. Computerized blood donor records in southern Brazil were examined for the period 2004–2006. The methods for estimating HBV incidence included stand-alone HBsAg, HBsAg yield method, and an extension of the latter which added recent anti-HBc seroconversions as incident HBV cases. Results. HBV incidences for the above methods were 9.91, 20.09, and 22.93 per 100000 repeat donors, respectively. In the same order, corresponding residual risks were 1 : 62482, 1 : 30821, and 1 : 47559, respectively. First-time donors had 52 higher HBV incidence compared to repeat donors. Conclusion. Although the three methods compared produced overlapping 95% confidence intervals, their variation was considerably lower for the method which included recent anti-HBc seroconversions. First-time donors are primary cause for concern regarding HBV transmission via blood transfusion in southern Brazil.

Hepatitis B and residual risk of infection in English and Welsh blood donors, 1996 through 2008

BACKGROUND

Globally, of all infections that donations are tested for, hepatitis B has the highest residual risk of transfusion transmission, despite donor selection criteria and advances in testing. Every blood donation in England and Wales is tested for hepatitis B surface antigen. Knowledge of infections being detected can inform donor selection and testing strategies.

STUDY DESIGN AND METHODS

Data on donation testing and infections detected are collated by the NHS Blood and Transplant and Health Protection Agency Epidemiology Unit. Infected donors are classified as having acute or chronic hepatitis B virus (HBV) by a clinician; their demographic characteristics were described. The prevalence (by acute or chronic HBV status, ethnicity, and geography) and incidence of infection were calculated between 1996 and 2008. The residual risk was calculated for four periods using a modification of the incidence and window period model; the effects of modifying variables were investigated.

RESULTS

Most infections (1047/1155) detected were chronic and seen in new donors. People with acute infections were more likely to be white and/or born in Western Europe. Prevalence was highest in donors from minority ethnic communities and in London. Incidence in repeat donors has halved in recent years. The estimated frequency of an infectious donation being missed was 1.37 per million donations (2006-2008), the lowest since surveillance began or three per year.

CONCLUSION

Many HBV infections in England and Wales were detected among new donors, who had chronic infection and were born overseas. The residual risk of infection declined over the 13 study years, but is still higher for HBV than other viral infections for which testing is undertaken.

The efficacy of individual-donation and minipool testing to detect low-level hepatitis B virus DNA in Taiwan

BACKGROUND

Financial constraints are the main concern in implementing nucleic acid testing (NAT) as routine blood screening in Taiwan. The PROCLEIX ULTRIO assay (Ultrio) on the TIGRIS System (Novartis Diagnostics) was evaluated for its operational performance both for individual-donation testing (IDT) and in minipools of 4 (MP4) to develop a feasible solution.

STUDY DESIGN AND METHODS

Analytical sensitivity was determined by testing WHO international standards. We tested 10,290 blood donors, 4210 in IDT and 6080 in MP4. Potential hepatitis B virus (HBV) yield donors (hepatitis B surface antigen [HBsAg] negative/NAT reactive) were evaluated for up to 9 months' follow-up. Discordant results between the Ultrio assay and the HBsAg tests were further analyzed by HBV antibody serology, alternative NATs, HBV DNA quantification, and sequencing.

RESULTS

The 95% limits of detection in IU/mL (95% confidence interval) were as follows: human immunodeficiency virus Type 1 (HIV-1), 18 (12-34); hepatitis C virus (HCV), 4.4 (2.8-8.9); and HBV, 6.3 (4.4-11). The retest rates were 0.55% for IDT and 0.33% for MP4. No HIV or HCV yield cases were found, while there were 12 potential HBV yield cases, nine from IDT and three from MP4 testing. Eleven of them were successfully genotyped as B2. Ten of them returned for follow-up and mostly were determined as occult HBV infection (OBI). The IDT yield rate of 9 in 4210 (0.21%) was fourfold greater than the MP4 yield rate of 3 in 6080 (0.05%; p < 0.05).

CONCLUSION

The higher yield rate for IDT versus MP4 demonstrates the benefit to implement a more sensitive NAT strategy in regions having significant OBI carriers such as Taiwan.

Comparison of the risk of viral infection between the living and nonliving musculoskeletal tissue donors in Australia

Screening of musculoskeletal tissue donors with nucleic acid testing (NAT) for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) has been implemented in the United States and other developed nations. However, in contrast to the donor demographics in the United States, the majority of Australian musculoskeletal tissue donations are primarily from living surgical donors. The objective of our study was to determine and compare the risk of viral infection associated with musculoskeletal tissue donation from living and nonliving donors in Australia. We studied serum samples from 12 415 consecutive musculoskeletal tissue donors between 1993 and 2004. This included 10 937 surgical donations, and 1478 donations obtained from postmortem organ donation patients and cadaveric donors. Current mandatory retesting of surgical donors 6 months postdonation reduces the risk of viral infection by approximately 95% by eliminating almost all donors in the window period. The addition of nucleic acid amplification testing for nonliving donors would similarly reduce the window period, and consequently the residual risk by approximately 50% for hepatitis B virus, 55% for HIV, and 90% for HCV. NAT, using appropriately validated assays for nonliving donors, would reduce the residual risk to levels comparable to that in living donors (where the 95% reduction for quarantining pending the 180-day re-test is included).

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.

The risk of HIV, HBV, HCV and HTLV infection among musculoskeletal tissue donors in Australia

In Australia, there are no current national estimates of the risks of transmission of human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) or human T-lymphotrophic virus (HTLV) by musculoskeletal tissue transplantation. We determined the prevalence rates of antibodies against HIV (anti-HIV), HCV (anti-HCV) and HTLV (anti-HTLV) and Hepatitis B surface antigen (HBsAg) for 12,415 musculoskeletal tissue donors from three major bone tissue banks across Australia for the period 1993-2004. The prevalence (per 100,000 persons) was 64.44 for anti-HIV, 407.13 for HBsAg, 534.63 for anti-HCV and 121.88 for anti-HTLV. The estimated probability of viremia at the time of donation was 1 in 128,000, 1 in 189,000, 1 in 55,000 and 1 in 118,000, respectively. With the addition of nucleic acid amplification testing (NAT), the probability of donor viremia would be reduced to 1 in 315,000 for HIV, 1 in 385,000 for HBV and 1 in 500,000 for HCV. The prevalence of HIV, HBV, HCV and HTLV although low, are higher among musculoskeletal tissue donors than among first-time blood donors. The risks associated with musculoskeletal donation will be reduced with NAT, though further cost analysis is required prior to its implementation.

A probabilistic model for analyzing viral risks of plasma-derived medicinal products

BACKGROUND

The prevention of transmission of viral infections by plasma-derived medicinal products is of concern to manufacturers, legislators, and patient representative groups. Recent European legislation requires a viral risk assessment for all new marketing applications of such products.

STUDY DESIGN AND METHODS

A discrete event Monte Carlo model was developed to determine the viral transmission risks of the plasma-derived medicinal products. The model incorporates donor epidemiology, donation intervals, efficiency of screening tests for viral markers, inventory hold period, size and composition of the manufacturing pool, production time, process virus reduction capacity, and product yield. With the model, the human immunodeficiency virus (HIV) and hepatitis C virus (HCV) contamination risks of a typical hypothetical plasma product were calculated, and the sensitivity of the risk to various model variables was analyzed.

RESULTS

The residual HIV and HCV risks of the finished products are linear in change with viral incidence rate and inversely linear with product yield and process virus reduction capacity. For the product analyzed in this article, the residual risk is less sensitive to changes in screening test pool size, donation frequency, and inventory hold period. There is only a limited dependency on the donation type (apheresis or whole-blood donations) and a negligible dependency on the manufacturing pool size.

CONCLUSIONS

The use of probabilistic model simulation techniques is indispensable when estimating realistic residual viral risks of plasma-derived medicinal products. In contrast to conventional deterministic residual risk estimations, the probabilistic approach allows incorporation of specific manufacturing decisions and therefore provides the only feasible alternative for a correct assessment of residual risks.

Blood transfusions in children: a multi-institutional analysis of practices and complications

BACKGROUND

Blood product transfusions are a valuable health-care resource. Guidelines for transfusion exist, but variability in their application, particularly in children, remains. The risk factors that threaten transfusion safety are well established, but because their occurrence in children is rare, single-institution studies have limited utility in determining the rates of occurrence. An epidemiologic approach that investigates blood transfusions in hospitalized children may help improve our understanding of transfused blood products in this vulnerable population.

STUDY DESIGN AND METHODS

This was a nonconcurrent cohort study of pediatric patients not more than 18 years of age hospitalized from 2001 to 2003 at 35 academic children's hospitals that are members of the Pediatric Health Information System (PHIS).

RESULTS

A total of 51,720 (4.8%) pediatric patients received blood product transfusions during the study period. Red blood cells (n = 44,632) and platelets (n = 14,274) were the two most frequently transfused products. The rate of transfusions was highest among children with neutropenia, agranulocytosis, and sickle cell crisis. Asian and American Indian patients had important differences in the rate of blood transfusions and their complications. Resource use in terms of length of stay and costs were higher in patients who received transfusion. Of those patients who received transfusions, 492 (0.95%) experienced a complication from the administered blood product. This accounted for a rate of complications of 10.7 per 1,000 units transfused.

CONCLUSIONS

The administration of blood products to children is a common practice in academic children's hospitals. Complications associated with these transfused products are rare.

The Domestication of AIDS: Stigma, Gender, and the Body Politic in Japan

In this article, I examine the processes by which AIDS has been "domesticated," and Japanese women stigmatized as vectors of HIV/AIDS, once regarded as a "foreign" disease in Japan. Women are associated with ritual pollution and impurity in the Shinto tradition. At the same time, Japanese women are blamed for eschewing marriage and motherhood in favor of material pursuits. As a sequel to the "AIDS panic" of the 1980s, which centered on "foreign women" and women who dated foreigners, in the late 1990s, the Japanese media incited widespread anxiety over a phenomenon known as enjo kosai, or "compensated dating," in which Japanese teenage girls are said to exchange favors (sometimes sexual) for money with older Japanese men. After describing the social and political conditions making the link between young girls, consumption, and AIDS appear natural in late 1990s Japan, I draw on material from some interviews with HIV-positive women to show how these women are marginalized by narratives that fail to take the particularity and the heterogeneity of their experiences into account. While these women resist the stigma that goes along with being labeled a "sex worker," their stories are drowned out by larger stories that speak of the body politic and national concerns over generation divides, demographic shifts, and gender relations in times of rapid social change.

Estimation of delay in detecting hepatitis C virus antibodies in pools compared to individual testing on seroconversion panels

Testing for anti-hepatitis C virus (HCV) antibodies in pools may reduce blood screening costs, making this approach affordable for developing countries, provided that the dilution of infected blood does not significantly increase the number of undetectable viral particles, especially in seroconverters. This study assessed the delay in detection of HCV antibodies in five HCV seroconversion panels, tested in pools of 6-48 samples, and estimated the risk of transfusion-transmitted HCV caused by pooling. The delay in detection of positive samples was 5-12 days for pools of all sizes, adding 7% to the risk of HCV transmission that occurs when blood donors' samples are tested individually.

Primary screening of blood donors by nat testing for HCV-RNA: development of an "in-house" method and results

An "in-house" RT-PCR method was developed that allows the simultaneous detection of the RNA of the Hepatitis C Virus (HCV) and an artificial RNA employed as an external control. Samples were analyzed in pools of 6-12 donations, each donation included in two pools, one horizontal and one vertical, permitting the immediate identification of a reactive donation, obviating the need for pool dismembering. The whole process took 6-8 hours per day and results were issued in parallel to serology. The method was shown to detect all six HCV genotypes and a sensitivity of 500 IU/mL was achieved (95% hit rate). Until July 2005, 139,678 donations were tested and 315 (0.23%) were found reactive for HCV-RNA. Except for five false-positives, all 310 presented the corresponding antibody as well, so the yield of NAT-only donations was zero, presenting a specificity of 99.83%. Detection of a window period donation, in the population studied, will probably demand testing of a larger number of donations. International experience is showing a rate of 1:200,000 - 1:500,000 of isolated HCV-RNA reactive donations.

Estimated benefits of transplantation of kidneys from donors at increased risk for HIV or hepatitis C infection

Kidneys from organ donors who have behaviors that place them at increased risk for infection with human immunodeficiency virus (HIV) or hepatitis C virus (HCV) are often discarded, even if viral screening tests are negative. This study compared policies that would either 'Discard' or 'Transplant' kidneys from Centers for Disease Control classified increased-risk donors (CDC-IRDs) using a decision analytic Markov model of renal failure treatment modalities. Base-case CDC-IRDs were current injection drug users (IDUs) with negative antibody and nucleic acid testing (NAT) for HIV and HCV, comprising 5% of kidney donors. Compared to a CDC-IRD kidney 'Discard' policy, the 'Transplant' policy resulted in higher patient survival, a greater number of quality-adjusted life-years (QALYs) (5.6 vs. 5.1 years per patient), more kidney transplants (990 vs. 740 transplants per 1000 patients) and lower cost of care ($60 000 vs. $71 000 per QALY). The total number of viral infections was lower with the 'Transplant' policy (13.1 vs. 14.8 infections per 1000 patients over 20 years), because the 'Discard' policy led to more time on hemodialysis, with a higher HCV incidence. We recommend that kidneys from NAT-negative CDC-IRDs be considered for transplantation since the practice is estimated to be beneficial from both the societal and individual patient perspective.

Current incidence and estimated residual risk of transfusion-transmitted infections in donations made to Canadian Blood Services

BACKGROUND

New testing methods such as nucleic acid amplification testing (NAT) and chemiluminescent serologic assays have been introduced, more precise estimates for infectious window periods are available, and a new method for estimating the residual risk (RR) of transfusion-transmitted infections (TTIs) has been developed. Thus, available RR estimates for Canada need to be updated.

STUDY DESIGN AND METHODS

Incidence rates for known TTI markers were determined for all allogeneic whole-blood donations made to Canadian Blood Services between 2001 and 2005; they were derived from NAT conversions or seroconversions of repeat donors with at least two donations in a 3-year period. RR estimates for human immunodeficiency virus (HIV)-1 and hepatitis C virus (HCV) derived from the classical incidence/window-period model were compared to those obtained by the new method that estimates incidence from NAT-positive, antibody-negative donations (NAT-yield cases) from all donors divided by person-years.

RESULTS

With the classical method, the RR of HIV (1 per 7.8 million donations) and HCV (1 per 2.3 million) were low; HBV RR was higher (1 per 153,000). HCV RR was significantly lower when estimated with the new method (1 per 13 million). Eleven HCV NAT-yield cases were predicted by applying the classical method to our seroconversion data but only 2 were observed (p = 0.011). Observed HIV-1 NAT-yield cases (n = 1) matched those predicted (n = 0.7).

CONCLUSION

New tests have reduced an already low risk of TTI in Canada. HCV RR estimates by two different methods differed but both were low.