Infection with human immunodeficiency virus type 1 (HIV-1) among recipients of antibody-positive blood donations

End of selection criteria based on sexual orientation: An international symposium on alternatives to donation deferral

BACKGROUND AND OBJECTIVES

Until recently, gay, bisexual and other men who have sex with men (MSM) were deferred from donating blood for 3-12 months since the last male-to-male sexual contact. This MSM deferral has been discontinued by several high-income countries (HIC) that now perform gender-neutral donor selection.

MATERIALS AND METHODS

An international symposium (held on 20-04-2023) gathered experts from seven HICs to (1) discuss how this paradigm shift might affect the mitigation strategies for transfusion-transmitted infections and (2) address the challenges related to gender-neutral donor selection.

RESULTS

Most countries employed a similar approach for implementing a gender-neutral donor selection policy: key stakeholders were consulted; the transition was bridged by time-limited deferrals; donor compliance was monitored; and questions or remarks on anal sex and the number and/or type of sexual partners were often added. Many countries have now adopted a gender-neutral approach in which questions on pre- and post-exposure prophylaxis for human immunodeficiency virus (HIV) have been added (or retained, when already in place). Other countries used mitigation strategies, such as plasma quarantine or pathogen reduction technologies for plasma and/or platelets.

CONCLUSION

The experience with gender-neutral donor selection has been largely positive among the countries covered herein and seems to be acceptable to stakeholders, donors and staff. The post-implementation surveillance data collected so far appear reassuring with regards to safety, although longer observation periods are necessary. The putative risks associated with HIV antiretrovirals should be further investigated.

Tumor oxygenation and cancer therapy-then and now

In 2012, cancer affected 14.1 million people worldwide and was responsible for 8.2 million deaths. The disease predominantly affects aged populations and is one of the leading causes of death in most western countries. In tumors, the aggressive growth of the neoplastic cell population and associated overexpression of pro-angiogenic factors lead to the development of disorganized blood vessel networks that are structurally and functionally different from normal vasculature. A disorganized labyrinth of vessels that are immature, tortuous and hyperpermeable typifies tumor vasculature. Functionally, the ability of the tumor vasculature to deliver nutrients and remove waste products is severely diminished. A critical consequence of the inadequate vascular networks in solid tumors is the development of regions of hypoxia [low oxygen tensions typically defined as oxygen tensions (pO₂ values) < 10 mm Hg]. Tumor cells existing in such hypoxic environments have long been known to be resistant to anticancer therapy, display an aggressive phenotype, and promote tumor progression and dissemination. This review discusses the physiological basis of hypoxia, methods of detection, and strategies to overcome the resulting therapy resistance.

Autoimmunity and dysmetabolism of human acquired immunodeficiency syndrome

Acquired immunodeficiency syndrome (AIDS) remains ill-defined by lists of symptoms, infections, tumors, and disorders in metabolism and immunity. Low CD4 cell count, severe loss of body weight, pneumocystis pneumonia, and Kaposi's sarcoma are the major disease indicators. Lines of evidence indicate that patients living with AIDS have both immunodeficiency and autoimmunity. Immunodeficiency is attributed to deficits in the skin- and mucosa-defined innate immunity, CD4 T cells and regulatory T cells, presumably relating human immunodeficiency virus (HIV) infection. The autoimmunity in AIDS is evident by: (1) overproduction of autoantibodies, (2) impaired response of CD4 cells and CD8 cells, (3) failure of clinical trials of HIV vaccines, and (4) therapeutic benefits of immunosuppression following solid organ transplantation and bone marrow transplantation in patients at risk of AIDS. Autoantibodies are generated in response to antigens such as debris and molecules de novo released from dead cells, infectious agents, and catabolic events. Disturbances in metabolic homeostasis occur at the interface of immunodeficiency and autoimmunity in the development of AIDS. Optimal treatments favor therapeutics targeting on the regulation of metabolism to restore immune homeostasis.

Extensive Genetic Diversity of HIV-1 in Incident and Prevalent Infections among Malaysian Blood Donors: Multiple Introductions of HIV-1 Genotypes from Highly Prevalent Countries

Transfusion-transmissible infections including HIV-1 continue to pose major risks for unsafe blood transfusions due to both window phase infections and divergent viruses that may not be detected by donor screening assays. Given the recent emergence of several HIV-1 circulating recombinant forms (CRFs) in high-risk populations in the Southeast Asia region, we investigated the genetic diversity of HIV-1 among the blood donors in Kuala Lumpur, Malaysia. A total of 211 HIV-positive plasma samples detected among 730,188 donations to the National Blood Centre between 2013 and 2014 were provided (90.5% male, median age: 27.0 years old). Recent or long-term infection status at the time of donation was determined using a limiting antigen avidity enzyme immunoassay (LAg-Avidity EIA). HIV-1 gag-pol genes were amplified and sequenced from residual plasma for 149 cases followed by genotype determination using phylogenetic and recombination analyses. Transmitted antiretroviral resistance mutations were not observed among the blood donors, among which 22.7% were classified as recent or incident infections. Major circulating HIV-1 genotypes determined by neighbour-joining phylogenetic inference included CRF01_AE at 40.9% (61/149), CRF33_01B at 21.5% (32/149), and subtype B at 10.1% (15/149). Newly-described CRFs including CRF54_01B circulated at 4.0%, CRF74_01B at 2.0%, and CRF53_01B and CRF48_01B at 0.7% each. Interestingly, unique HIV-1 genotypes including African subtype G (8.7%), CRF45_cpx (1.3%), CRF02_AG (0.7%) and CRF07_BC (0.7%) from China were detected for the first time in the country. A cluster of subtype G sequences formed a distinct founder sub-lineage within the African strains. In addition, 8.7% (13/149) of HIV-infected donors had unique recombinant forms (URFs) including CRF01_AE/B' (4.7%), B'/C (2.7%) and B'/G (1.3%) recombinants. Detailed analysis identified similar recombinant structures with shared parental strains among the B'/C and B'/G URFs, some of which were sequenced from recently infected individuals, indicating the possible emergence and on-going spread of foreign clades of CRF candidates among the local population. The findings demonstrate extensive molecular complexity of HIV-1 among the infected blood donors in Malaysia, driven in part by the increased spread of recently described CRFs and multiple introductions of previously unreported genotypes from highly prevalent countries.

Short Communication: Investigating a Chain of HIV Transmission Events Due to Homosexual Exposure and Blood Transfusion Based on a Next Generation Sequencing Method

This study investigates a chain of HIV transmission events due to homosexual exposure and blood transfusion in China. The MiSeq platform, a next generation sequencing (NGS) system, was used to obtain genetic details of the HIV-1 env region (336 base pairs). Evolutionary analysis combined with epidemiologic evidence suggests a transmission chain from patient T3 to T2 through homosexual exposure and subsequently to T1 through blood transfusion. More importantly, a phylogenetic study suggested a likely genetic bottleneck for HIV in homosexual transmission from T3 to T2, while T1 inherited the majority of variants from T2. The result from the MiSeq platform is consistent with findings from the epidemiologic survey. The MiSeq platform is a powerful tool for tracing HIV transmissions and intrapersonal evolution.

Estimating per-act HIV transmission risk: a systematic review

BACKGROUND

Effective HIV prevention programs rely on accurate estimates of the per-act risk of HIV acquisition from sexual and parenteral exposures. We updated the previous risk estimates of HIV acquisition from parenteral, vertical, and sexual exposures, and assessed the modifying effects of factors including condom use, male circumcision, and antiretroviral therapy.

METHODS

We conducted literature searches to identify new studies reporting data regarding per-act HIV transmission risk and modifying factors. Of the 7339 abstracts potentially related to per-act HIV transmission risk, three meta-analyses provided pooled per-act transmission risk probabilities and two studies provided data on modifying factors. Of the 8119 abstracts related to modifying factors, 15 relevant articles, including three meta-analyses, were included. We used fixed-effects inverse-variance models on the logarithmic scale to obtain updated estimates of certain transmission risks using data from primary studies, and employed Poisson regression to calculate relative risks with exact 95% confidence intervals for certain modifying factors.

RESULTS

Risk of HIV transmission was greatest for blood transfusion, followed by vertical exposure, sexual exposures, and other parenteral exposures. Sexual exposure risks ranged from low for oral sex to 138 infections per 10,000 exposures for receptive anal intercourse. Estimated risks of HIV acquisition from sexual exposure were attenuated by 99.2% with the dual use of condoms and antiretroviral treatment of the HIV-infected partner.

CONCLUSION

The risk of HIV acquisition varied widely, and the estimates for receptive anal intercourse increased compared with previous estimates. The risk associated with sexual intercourse was reduced most substantially by the combined use of condoms and antiretroviral treatment of HIV-infected partners.

The use of Nanotrap particles technology in capturing HIV-1 virions and viral proteins from infected cells

HIV-1 infection results in a chronic but incurable illness since long-term HAART can keep the virus to an undetectable level. However, discontinuation of therapy rapidly increases viral burden. Moreover, patients under HAART frequently develop various metabolic disorders and HIV-associated neuronal disease. Today, the main challenge of HIV-1 research is the elimination of the residual virus in infected individuals. The current HIV-1 diagnostics are largely comprised of serological and nucleic acid based technologies. Our goal is to integrate the nanotrap technology into a standard research tool that will allow sensitive detection of HIV-1 infection. This study demonstrates that majority of HIV-1 virions in culture supernatants and Tat/Nef proteins spiked in culture medium can be captured by nanotrap particles. To determine the binding affinities of different baits, we incubated target molecules with nanotrap particles at room temperature. After short sequestration, materials were either eluted or remained attached to nanotrap particles prior to analysis. The unique affinity baits of nanotrap particles preferentially bound HIV-1 materials while excluded albumin. A high level capture of Tat or Tat peptide by NT082 and NT084 particles was measured by western blot (WB). Intracellular Nef protein was captured by NT080, while membrane-associated Nef was captured by NT086 and also detected by WB. Selective capture of HIV-1 particles by NT073 and NT086 was measured by reverse transcriptase assay, while capture of infectious HIV-1 by these nanoparticles was demonstrated by functional transactivation in TZM-bl cells. We also demonstrated specific capture of HIV-1 particles and exosomes-containing TAR-RNA in patients' serum by NT086 and NT082 particles, respectively, using specific qRT-PCR. Collectively, our data indicate that certain types of nanotrap particles selectively capture specific HIV-1 molecules, and we propose to use this technology as a platform to enhance HIV-1 detection by concentrating viral proteins and infectious virions from infected samples.

BLT humanized mice as model to study HIV vaginal transmission

The majority of human immunodeficiency virus type 1 (HIV-1) infections occur by sexual exposure, and vaginal transmission accounts for more than half of all newly acquired infections. Studies of vaginal transmission of simian immunodeficiency virus to nonhuman primates (NHPs) have suggested an important role for immune cell trafficking in the establishment of infection as well is in the process of viral dissemination. However, NHP models do not permit the study of HIV transmission and dissemination. The improvement of humanized mouse models with robust human immune cell reconstitution of the female genital tract renders these mice susceptible to intravaginal HIV infection. Thus humanized mouse models of HIV vaginal infection will allow the study of the mechanisms involved in HIV transmission and dissemination in vivo.

O uso da argumentação científica na opção por estilos de vida arriscados no cenário da aids

Investigam-se os usos de argumentos científicos que circulam no cotidiano de homens que fazem sexo com homens (HSH), em parceria casual, como estratégia para gerir riscos associados às práticas sexuais. O aporte teórico da pesquisa refere-se às práticas discursivas sobre estilos de vida arriscados no cenário da aids. Por meio da técnica snowball foram selecionados sete participantes, que responderam a uma entrevista semiestruturada. Os resultados indicam a assimilação de informações científicas que circulam no cotidiano dos interlocutores deste estudo interpretadas como potencial fonte na gestão de riscos. Esses homens desenvolvem estratégias de gestão de risco de infecção por DST, HIV e/ou a reinfecção pelo HIV sem basear-se, necessariamente, nas políticas oficiais de prevenção do governo brasileiro.

Reducing infection transmission in solid organ transplantation through donor nucleic acid testing: a cost-effectiveness analysis

For solid organ transplant (SOT) donors, nucleic acid-amplification testing (NAT) may reduce human immunodeficiency virus (HIV) and hepatitis C virus (HCV) transmission over antibody (Ab) testing given its shorter detection window period. We compared SOT donor NAT + Ab versus Ab alone using decision models to estimate incremental cost-effectiveness ratios (ICERs; cost per quality-adjusted life year [QALY] gained) from the societal perspective across a range of HIV/HCV prevalence values and NAT costs. The cost per QALY gained was calculated for two scenarios: (1) favorable: low cost ($150/donor)/high prevalence (HIV: 1.5%; HCV: 18.2%) and (2) unfavorable: high cost ($500/donor)/low prevalence (HIV: 0.1%; HCV: 1.5%). In the favorable scenario, adding NAT screening cost $161 013 per QALY gained for HIV was less costly) for HCV, and cost $86 653 per QALY gained for HIV/HCV combined. For the unfavorable scenario, the costs were $15 568 484, $221 006 and $10 077 599 per QALY gained, respectively. Universal HCV NAT + Ab for donors appears cost-effective to reduce infection transmission from SOT donors, while HIV NAT + Ab is not, except where HIV NAT is ≤$150/donor and prevalence is ≥1.5%. Our analyses provide important data to facilitate the decision to implement HIV and HCV NAT for deceased SOT donors and shape national policy regarding how to reduce infection transmission in SOT.

Blood supply safety in Afghanistan: a national assessment of high-volume facilities

BACKGROUND

Little information is available regarding blood supply safety in Afghanistan. The purpose of this study was to assess blood safety through serologic and observational measures in Afghanistan.

STUDY DESIGN AND METHODS

This cross-sectional assessment included the 40 highest-volume facilities collecting and transfusing blood nationally identified in a previous survey. At each facility, study representatives completed a standardized instrument assessing staff performance of transfusion-related activities and performed rapid testing for human immunodeficiency virus, syphilis, and hepatitis B and C with rapid diagnostic tests on clinically discarded specimens. Reactive samples received confirmatory testing. Descriptive statistics were generated, with differences analyzed using chi-square or Fisher's exact tests.

RESULTS

Between November 2010 and May 2011, a total of 332 blood donor collection procedures were observed. Only 52.4% of observed encounters correctly screened and deferred donors by international criteria. Public and private facilities demonstrated glove use, proper sharps disposal, and patient counseling and relayed screening test results in less than 75% of observed events, significantly less likely than military facilities (p < 0.01). Of 1612 specimens assessed, confirmed cases of hepatitis B (n = 6), hepatitis C (n = 1), and syphilis (n = 3) were detected among units already prescreened and accepted for transfusion.

CONCLUSION

Lapses in proper donor screening contributed to the presence of confirmed-positive units available for transfusion, as detected in this study. Steps must be taken to ensure standardization of testing kits requirements, documentation, and mandatory training and continuing education for blood bank staff with regard to counseling, drawing, processing, and transfusion of blood products.

AIDS denialism and public health practice

In this paper, we respond to AIDS denialist arguments that HIV does not cause AIDS, that antiretroviral drugs are not useful, and that there is no evidence of large-scale deaths from AIDS, and discuss the key implications of the relationship between AIDS denialism and public health practice. We provide a brief history of how the cause of AIDS was investigated, of how HIV fulfills Koch's postulates and Sir Bradford Hil's criteria for causation, and of the inconsistencies in alternatives offered by denialists. We highlight clinical trials as the standard for assessing efficacy of drugs, rather than anecdotal cases or discussions of mechanism of action, and show the unanimous data demonstrating antiretroviral drug efficacy. We then show how statistics on mortality and indices such as crude death rate, life expectancy, child mortality, and population growth are consistent with the high mortality from AIDS, and expose the weakness of statistics from death notification, quoted by denialists. Last we emphasize that when denialism influences public health practice as in South Africa, the consequences are disastrous. We argue for accountability for the loss of hundreds of thousands of lives, the need to reform public health practice to include standards and accountability, and the particular need for honesty and peer review in situations that impact public health policy.

A forensic nursing protocol for initiating human immunodeficiency virus post-exposure prophylaxis following sexual assault

The use of human immunodeficiency virus post-exposure prophylaxis (HIV PEP) should be considered in the care of sexual assault patient populations. In order to effectively implement HIV PEP following sexual assault, healthcare providers need to have a working knowledge of HIV transmission risk factors following a sexual exposure and protocols for initiating HIV PEP. Being able to implement evidence-based practices that address each of these factors is paramount to successful prevention of HIV transmission following a sexual assault exposure. Most healthcare practitioners, however, lack the specialized knowledge needed to address these issues in the expeditious manner necessitated by a potential HIV exposure.

IMPLICATIONS

This paper is designed to provide healthcare providers with a basic understanding of HIV transmission risk factors and the knowledge and skills needed to effectively implement HIV PEP following a sexual assault exposure.

The risk of transfusion-transmitted infections in sub-Saharan Africa

BACKGROUND

Blood transfusions carry the risk of transmitting infections. This risk has been studied in detail in high-income countries but not in sub-Saharan Africa. This study estimates the risks of acquiring human immunodeficiency virus (HIV), hepatitis B virus (HBV), or hepatitis C virus (HCV) from a single unit of blood in sub-Saharan Africa.

STUDY DESIGN AND METHODS

A mathematical model was constructed to quantify transfusion risks across 45 sub-Saharan African countries using three components: the risk of a contaminated unit entering the blood supply, the risk that the unit will be given to a susceptible patient, and the risk that receipt of the unit will lead to infection in the recipient. Variables included prevalence of infection in donors, extent of blood testing, test sensitivity, and susceptibility of recipients. Data from the World Health Organization (WHO) African Region and a systematic review of the literature were used to parameterize the model. Uncertainty in the risk estimates was quantified using probabilistic sensitivity analysis.

RESULTS

The median overall risks of becoming infected with HIV, HBV, and HCV from a blood transfusion in sub-Saharan Africa were 1, 4.3, and 2.5 infections per 1000 units, respectively. If annual transfusion requirements projected by the WHO were met, transfusions alone would be responsible for 28,595 HBV infections, 16,625 HCV infections, and 6650 HIV infections every year. Sensitivity analysis suggests that the true risks may be even higher.

CONCLUSIONS

This study is the first to systematically quantify the risks of transfusion-transmitted infections across sub-Saharan Africa. Although the results are limited by the quality and quantity of available data, these may be the most reliable estimates at this time.

Overview of HIV

This article provides an overview and reviews the HIV pandemic, the basic biology and immunology of the virus (e.g., genetic diversity of HIV and the viral life cycle), the phases of disease progression, modes of HIV transmission, HIV testing, immune response to the infection, and current therapeutic strategies. HIV is occurring in epidemic proportions, especially in Sub-Saharan Africa. In the US, men who have sex with men account for over half of AIDS diagnoses; racial and ethnic minorities are disproportionally affected. Factors influencing the progression and severity of HIV infection include type of immune response, coinfection (e.g., another sexually transmitted infection, including hepatitis B or C), age and behavioral and psychosocial factors. Antiretroviral therapies can achieve reduction in blood levels of the HIV virus below the limits of detection by current technology. However, effective treatment requires adherence to therapy. Patient failure to adhere to treatment regimens results in detectible circulating virus and in HIV disease progression, and is the primary cause of drug resistance. In addition to research on the immunology and virology of the disease, other studies focus on behavioral and psychosocial factors that may affect medication adherence and risk behaviors.

Residual infectious disease risk in screened blood transfusion from a high-prevalence population: Santa Catarina, Brazil

BACKGROUND

Infectious disease testing has improved but viral infection transmission through transfusion continues to occur. Residual risk, however, is now so low in some countries that it can only be estimated by mathematical modeling. With hierarchical Bayesian methods, this study estimates the residual risk of transfusion-transmitted infections in Santa Catarina, Brazil.

STUDY DESIGN AND METHODS

Data from the six state blood collection services covering Santa Catarina between 1998 and 2002 were used. Information was obtained on donor profiles, screening and confirmatory test results, and records of all allogeneic blood donations for repeat donors. Residual risk estimates of hepatitis B virus (HBV), human immunodeficiency virus (HIV), hepatitis C virus (HCV), and human T-cell leukemia virus (HTLV) were separately derived from posterior distributions of incidence rates and preseroconversion window-period lengths.

RESULTS

Estimated risks of a donation infectious for HBV and HIV entering the blood supply are 1:10,700 (95% confidence interval [CI], 1:4900-1:28,200) and 1:26,200 (95% CI, 1:14,800-1:64,100) donations, respectively. Estimated risks for HCV and HTLV were 1:19,300 (95% CI, 1:10,400-1:44,800) and 1:116,300 (95% CI, 1:40,200-1:1,000,000) donations, respectively. HBV risk is 1.8 times greater than HCV risk, 2.4 times greater than HIV risk, and 10.8 times that of HTLV. Actual risks would be lower due to immune recipients and subinfectious levels of undetected viremia.

CONCLUSION

The major factor contributing to risk differences between Santa Catarina and countries with similar testing regimes is the much higher source population diseases prevalence. Payoff for nucleic acid testing would be low, thus additional investment in safety should be based on studies of the cost-effectiveness of different strategies to reduce overall transmission.

Pediatric and adolescent HIV disease

OBJECTIVE

To review the current literature and guidelines for pediatric and adolescent human immunodeficiency virus (HIV) diagnosis and treatment.

DATA SOURCES

MEDLINE and the Centers for Disease Control and Prevention Web sites were searched to obtain relevant articles.

STUDY SELECTION

The expert opinions of the authors were used to design cases that highlight the studies and guidelines reviewed.

RESULTS

There have been numerous advances in the prevention, diagnosis, and treatment of pediatric and adolescent HIV disease in the past decade. Now, HIV is a chronic illness managed with medication, when appropriate. The HIV transmission rate from mother to child is very low (approximately 1%) in industrialized countries because antiretroviral agents are now available to pregnant women. The pill burden for children and adults with HIV has plummeted from 8 to 10 pills 3 times daily to 3 to 5 pills once daily in the best-case scenarios. A shift has occurred in HIV care from treating opportunistic illnesses to promoting adherence and avoiding drug resistance while monitoring medication adverse effects.

CONCLUSIONS

Diagnosis and treatment of HIV is a rapidly changing field with frequently changing guidelines. The coming years may bring already available technology to the rest of the world and advances toward the prevention and cure of HIV.

Characterization of blood-borne transmission of simian foamy virus

BACKGROUND

Simian foamy virus (SFV) is an endemic, nonhuman primate (NHP) retrovirus that is transmitted to individuals who work with or hunt NHPs. The cross-species transmission of simian retroviruses is believed to be the etiology of human immunodeficiency virus and human T-lymphotropic virus infections in humans. Although SFV is not pathogenic in the native host, the shared ancestry with other simian retroviruses has brought into question the potential for acquired pathogenicity after cross-species transmission. This study examines whether SFV also shares the traits of transmissibility through the blood supply.

STUDY DESIGN AND METHODS

Within a controlled environment, blood from an SFV-infected monkey was transfused into an SFV-uninfected monkey. Evidence of infection, pathogenic effects, immune correlates, and viral shedding were followed for 6 months after transfusion.

RESULTS

Molecular evidence of SFV infection manifested 8 weeks after transfusion followed by seroconversion 1 week later. Quantitative analysis demonstrated that the highest level of detectable virus was concomitant with seroconversion followed by establishment of a viral "set-point." Analysis of circulating lymphocytes revealed changes early in infection. Potential routes of transmission of SFV and roles of site-specific immune response are suggested by the late appearance of SFV shedding in the saliva of the transfused animal.

CONCLUSION

The blood supply has historically provided a portal through which novel, occult viruses can become disseminated among humans. The demonstration of transmissibility of SFV through whole-blood transfusion, in an NHP model, contributes to the understanding of potential risks associated with blood donation by SFV-infected humans.

AIDS: The Second Wave

Over two decades ago, the first cases of a new disease now known as AIDS were described in the literature. Since then, remarkable advances have been made, a new retrovirus has been discovered, promising antiviral agents have been developed and affordable and effective preventive interventions exists. Yet the AIDS pandemic continues largely unabated. AIDS is the world's leading infectious disease cause of death and threatens to devastate the economic systems of resource-poor nations. Over the next decade the HIV epidemic is expected to continue to grow with an increasing proportion of infected persons residing in developing countries and increasingly affecting young women. However, reducing the burden of HIV/AIDS is achievable, and there is some cause for cautious optimism.

The RADAR repository: a resource for studies of infectious agents and their transmissibility by transfusion

BACKGROUND

An ongoing issue in transfusion medicine is whether newly identified or emerging pathogens can be transmitted by transfusion. One method to study this question is through the use of a contemporary linked donor-recipient repository.

STUDY DESIGN AND METHODS

The Retrovirus Epidemiology Donor Study Allogeneic Donor and Recipient (RADAR) repository was established between 2000 and 2003 by seven blood centers and eight collaborating hospitals. Specimens from consented donors were collected, components from their donations were routed to participating hospitals, and recipients of these units gave enrollment and follow-up specimens for long-term storage. The repository was designed to show that zero transmissions to enrolled recipients would indicate with 95 percent confidence that the transfusion transmission rate of an agent with prevalence of 0.05 to 1 percent was lower than 25 percent.

RESULTS

The repository contains pre- and posttransfusion specimens from 3,575 cardiac, vascular, and orthopedic surgery patients, linked to 13,201 donation specimens. The mean number of RADAR donation exposures per recipient is 3.85. The distribution of components transfused is 77 percent red cells, 13 percent whole blood-derived platelet concentrates, and 10 percent fresh frozen plasma. A supplementary unlinked donation repository containing 99,906 specimens from 84,339 donors was also established and can be used to evaluate the prevalence of an agent and validate assay(s) performance before accessing the donor-recipient-linked repository. Recipient testing conducted during the establishment of RADAR revealed no transmissions of human immunodeficiency virus, hepatitis C virus, or human T-lymphotropic virus.

CONCLUSIONS

RADAR is a contemporary donor-recipient repository that can be accessed to study the transfusion transmissibility of emerging agents.

Risks of seroconversion of hepatitis B, hepatitis C and human immunodeficiency viruses in children with multitransfused thalassaemia major

OBJECTIVES

To estimate the risks of seroconversion of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency viruses (HIV) in children with multitransfused thalassaemia at a thalassaemic clinic in Kuala Lumpur, Malaysia.

METHODS

Seventy-two children (39 males, median age 11.3 years, 2.5th-97.5th centile: 1.4-19.2 years) with thalassaemia major were studied. The risks of seroconversion of HBV, HCV and HIV were estimated by comparing the seroprevalences of hepatitis B surface antigen (HBsAg), anti-HCV and anti-HIV between a defined starting point and an end point. The end point was the point when latest serological results were available while the starting point was when regular transfusion was commenced, or approximately 5 years before the end point when the duration of transfusion was longer.

RESULTS

The median duration of the study was 49 months (range 8-69 months, total 2953 patient-months). There were 2605 transfusion episodes and 4154 units of blood transfused (0.88 transfusion episode/patient per month, 1.41 units of blood transfused/patient per month). There were three new seroconversions for anti-HCV but none for HBsAg and anti-HIV. The risk of seroconversion for HCV was one in 1384 units of blood transfused (95% CI: 4000-472). The seroprevalence rates at the starting and end points were: HBsAg (1%, 1%), anti-HCV (10%, 13%) and anti-HIV (0%, 0%), respectively.

CONCLUSIONS

The estimated risk of acquiring HCV infection in children receiving multiple blood transfusions in this study is surprisingly higher than the generally accepted estimated risk. Other routes of transmission may be important. A prospective, multicentre study to estimate such risks more precisely is needed.

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.

Prophylaxis of HIV infection

The number of people infected with HIV continues to increase relentlessly. Post-exposure prophylaxis (PEP) following exposure to HIV infection may prevent established HIV infection. Such intervention is supported by biological plausibility and limited data from animal and human studies. Antiretroviral prophylaxis is associated with significant side effects and the risk should be weighed against the potential benefits. PEP should be considered after significant occupational and non-occupational exposures. However, PEP is not suitable for individuals with repeated high-risk behaviour who are not willing to adhere to risk reduction practices. Primary prevention strategies remain the mainstay for control of the HIV epidemic and cannot be replaced by PEP. Guidance for PEP following exposure to HIV infection is available in many countries worldwide.

Postexposure prophylaxis in children and adolescents for nonoccupational exposure to human immunodeficiency virus

Exposure to human immunodeficiency virus (HIV) can occur in a number of situations unique to, or more common among, children and adolescents. Guidelines for postexposure prophylaxis (PEP) for occupational and nonoccupational (eg, sexual, needle-sharing) exposures to HIV have been published by the US Public Health Service, but they do not directly address nonoccupational HIV exposures unique to children (such as accidental exposure to human milk from a woman infected with HIV or a puncture wound from a discarded needle on a playground), and they do not provide antiretroviral drug information relevant to PEP in children. This clinical report reviews issues of potential exposure of children and adolescents to HIV and gives recommendations for PEP in those situations. The risk of HIV transmission from nonoccupational, nonperinatal exposure is generally low. Transmission risk is modified by factors related to the source and extent of exposure. Determination of the HIV infection status of the exposure source may not be possible, and data on transmission risk by exposure type may not exist. Except in the setting of perinatal transmission, no studies have demonstrated the safety and efficacy of postexposure use of antiretroviral drugs for the prevention of HIV transmission in nonoccupational settings. Antiretroviral therapy used for PEP is associated with significant toxicity. The decision to initiate prophylaxis needs to be made in consultation with the patient, the family, and a clinician with experience in treatment of persons with HIV infection. If instituted, therapy should be started as soon as possible after an exposure-no later than 72 hours-and continued for 28 days. Many clinicians would use 3 drugs for PEP regimens, although 2 drugs may be considered in certain circumstances. Instruction for avoiding secondary transmission should be given. Careful follow-up is needed for psychologic support, encouragement of medication adherence, toxicity monitoring, and serial HIV antibody testing.

Risks associated with transfusion of cellular blood components in Canada

We provide a comprehensive review of risks associated with allogeneic red blood cell and platelet transfusions in Canada. The review focuses on clinically symptomatic noninfectious transfusion risks (acute and delayed hemolytic, febrile nonhemolytic [FNHTR], allergic, volume overload, transfusion-related acute lung injury, graft-versus-host disease, and posttransfusion purpura) and the risk of clinically significant disease from transfusion-transmitted infections. Data sources include information from Canadian Blood Services, Héma-Québec, Health Canada, and the Québec Hemovigilance System as well as published information from research studies and international hemovigilance systems. We estimate that in 2000 the aggregate risk of potentially severe reactions (excluding FNHTR and minor allergic reactions) was 43.2 per 100000 red cell units (95% confidence interval [CI]: 38.7-48.1), affecting 337 recipients, and 125.7 per 100000 platelet pools of 5 units (95% CI: 100.8-154.9), affecting 88 recipients. The most frequent potentially severe outcomes for red cell transfusion were hemolytic reactions and volume overload and for platelet transfusion were major allergic reactions and bacterial contamination. The current risk of human immunodeficiency virus and hepatitis C virus transmission is approximately 1 in 4 million and 1 in 3 million units, respectively. These estimates are useful for decisions concerning transfusion therapy, the informed consent process, and for evaluating efficacy of interventions to reduce risk.

Making a therapeutic choice: human versus recombinant fractions - can we do it?

New manufacturing methods have resulted in production of higher purity human-derived products and recombinant factors with less human- or animal-derived reagents or stabilizers for the treatment of congenital coagulation disorders. In addition, new viral inactivation processes are being used to reduce the chance of viral contamination. Preferred treatment approaches are moving toward using newer-generation agents. At the same time, rationale exists for continuing fractionation of all types of products, based on considerations including cost, product availability, safety issues, and specific clinical situations for which a recombinant or high-purity product is not available. These issues and others are reviewed in the context of making a therapeutic choice.

The risks of transfusion-transmitted infection: direct estimation and mathematical modelling

Direct measurement of the risk of transfusion-transmitted infection (TTI) is practical and accurate only if the level of risk is high. Historically, studies that established frozen repositories of transfusion recipient and/or blood donor samples were important in establishing the risk of many TTI agents, including the human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV). However, given the current very low risk of TTI, mathematical modelling is necessary to estimate the magnitude of such a risk. For agents for which routine blood donor screening is performed, most of this risk comes from transfusion of units collected in the window period between donor infection and a positive blood screening assay. The incidence/window period model has been used to estimate the magnitude of such risks (of the order of 1:100 000 to 1:1 000 000) and for predicting the extent of risk reduction that can be expected with implementation of new tests. Direct estimation and mathematical modelling approaches are both important tools for future assessment of potential, new or emerging TTI agents.

Nonoccupational HIV postexposure prophylaxis: a new role for the emergency department

Despite numerous primary prevention campaigns, new cases of HIV infection are occurring at high rates. Postexposure prophylaxis (PEP) after possible HIV exposures from sexual encounters or injection drug use may prove to be a worthwhile means of reducing HIV infection. Although there are no studies that directly demonstrate its efficacy, indirect support comes from animal and human studies. Multiple animal studies have shown that antiretroviral medications can reduce simian immunodeficiency virus infections if given early and for a prolonged period. A study of health care workers suggests that zidovudine taken after needlestick injuries can dramatically reduce HIV seroconversion. Zidovudine and nevirapine use recently showed great reductions in perinatal HIV transmission. Studies of dendritic and T-cell processing of simian immunodeficiency virus and HIV indicate that antiretroviral medications taken soon after a viral exposure may terminate viral replication. Regimens of 2 or 3 antiretroviral medications have been suggested as prophylactic measures after certain exposures. Even though limited experience exists with these populations, HIV PEP is most likely safe in pregnancy and for children. Emergency departments are encouraged to anticipate the probable demands for nonoccupational HIV PEP by establishing protocols for its rapid provision and ensuring proper follow-up care.

Transfusion-transmitted infectious diseases in Argentina, 1995 through 1997

BACKGROUND

Assessment of the safety of the blood supply, the quality of screening procedures, and the risk of transfusion transmission of infectious diseases in any country can be estimated by reviewing the records of blood donations and screening procedures and the prevalence of serologic markers of infectious diseases.

STUDY DESIGN AND METHODS

Information on blood donors, particularly the number of screened donors, and on the prevalence of serologic markers of infectious diseases was available from Argentina for 1995 through 1997. This information permitted the estimation of the risks and costs of preventing transfusion transmission of infectious diseases within the country during this period.

RESULTS

Screening coverage was higher in the private sector. The proportion of donors screened for HIV increased from 84.52 percent in 1995 to 97.97 percent in 1997; in the same period, serologic screening for HbsAg increased from 83.71 percent to 98.48 percent; that for HCV from 69. 92 percent to 97.83 percent; and that for syphilis from 87.94 percent to 98.71 percent. One hundred percent of donors were screened for Trypanosoma cruzi throughout the period. The overall prevalence of HIV per year varied from 2.42 to 3.36 per 1,000 donors; that of HBV, from 5.80 to 9.76 per 1,000; of HCV, from 7.39 to 16.61 per 1,000; and of syphilis, from 5.25 to 7.65 per 1,000. The overall prevalence of antibodies to T. cruzi ranged from 36.53 to 49.20 per 1,000 donors. The overall index of the spread of infectious viral disease through blood transfusion decreased from 47. 74 per 10,000 donations in 1995 to 4.75 per 10,000 in 1997. The ratio of acquired infections to donations improved from 1:209 to 1:2, 102 during the same period. The risk of T. cruzi infection from 1995 through 1997 was, in theory, nil, given the 100-percent screening. The greatest threat to the quality of the blood supply throughout the period studied was HCV.

CONCLUSION

The status of the blood supply in Argentina improved steadily from 1995 to 1997, as shown by the increase in screening coverage.