Nucleic Acid Amplification Test Screening Research Articles

Sexual and gender minority relevant policies in Canadian and United States organ and tissue donation and transplantation systems: An opportunity to improve equity and safety

Current policies in organ and tissue donation and transplantation (OTDT) systems in Canada and the United States unnecessarily restrict access to donation for sexual and gender minorities (SGMs) and pose safety risks to transplant recipients. We compare SGM-relevant policies between the Canadian and United States systems. Policy domains include the risk assessment of living and deceased organ and tissue donors, physical examination considerations, viral testing recommendations, and informed consent and communication. Identified gaps between current evidence and existing OTDT policies along with differences in SGM-relevant policies between systems, represent an opportunity for improvement. Specific recommendations for OTDT system policy revisions to achieve these goals include the development of behavior-based, gender-neutral risk assessment criteria, a reduction in current SGM no-sexual contact period requirements pending development of inclusive criteria, and destigmatization of sexual contact with people living with human immunodeficiency virus. OTDT systems should avoid rectal examinations to screen for evidence of receptive anal sex without consent and mandate routine nucleic acid amplification test screening for all donors. Transplant recipients must receive enhanced risk-to-benefit discussions regarding decisions to accept or decline an offer of an organ classified as increased risk. These recommendations will expand the donor pool, enhance equity for SGM people, and improve safety and outcomes for transplant recipients.

Impact of SARS-CoV-2 Arrival Surveillance Screening by Nucleic Acid Amplification Versus Rapid Antigen Detection on Subsequent COVID-19 Infections in Military Trainees.

For persons entering congregate settings, optimal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) arrival surveillance screening method, nucleic acid amplification test (NAAT) versus rapid antigen detection test (RADT), is debated. To aid this, we sought to determine the risk of secondary symptomatic coronavirus disease 19 (COVID-19) among military trainees with negative arrival NAAT or RADT screening. Individuals who arrived for US Air Force basic military training from 1 January-31 August 2021 were placed into training groups and screened for SARS-CoV-2 via NAAT or RADT. Secondary symptomatic COVID-19 cases within 2 weeks of training were then measured. A case cluster was defined as ≥5 individual symptomatic COVID-19 cases. 406 (1.6%) of 24 601 trainees screened positive upon arrival. The rate of positive screen was greater for those tested with NAAT versus RADT (2.5% vs 0.4%; RR: 5.4; 95% CI: 4.0-7.3; P < .001). The proportion of training groups with ≥1 positive individual screen was greater in groups screened via NAAT (57.5% vs 10.8%; RR: 5.31; 95% CI: 3.65-7.72; P < .001). However, NAAT versus RADT screening was not associated with a difference in number of training groups to develop a secondary symptomatic case (20.3% vs 22.5%; RR: .9; 95% CI: .66-1.23; P = .53) or case cluster of COVID-19 (4% vs 6.6%; RR: .61; 95% CI: .3-1.22; P = .16). NAAT versus RADT arrival surveillance screening method impacted individual transmission of COVID-19 but had no effect on number of training groups developing a secondary symptomatic case or case cluster. This study provides consideration for RADT arrival screening in congregate settings.

Effectiveness of Using Nucleic Acid Amplification Test to Screen Blood Donors for Hepatitis B, Hepatitis C, and HIV: A Tertiary Care Hospital Experience From Pakistan.

Background Ensuring blood safety is the primary goal of transfusion medicine. Despite extensive serological tests and strict safety measures, the risk of transfusion-transmitted infections (TTIs) still exists. As applied to blood screening, Nucleic Acid Amplification Test (NAT)offers much higher sensitivity for detecting viral infections. It is, however, currently available to a handful of centers due to the high cost. This study aims to establish the Effectiveness of NAT by assessing the NAT yield and residual risk of transmission of Hepatitis B virus (HBV), hepatitis C virus (HCV)and HIV with and without NAT testing. Material and method This prospective cross-sectional study recruited blood donors from January 2020 to November 2022. All donors underwent routine serologic screening. Only serologically negative donors were tested for HBV, HCV, and HIV by NAT. The NAT yield and residual risk (RR) per million donors were computed for viral infections in seronegative blood donors and calculated using the incidence/window period model. Result A total of 59708 donors were included during the study period. The overall prevalence of TTI's were: For HCV 1.7% (n = 1018), HBV 1.5% (n = 918), HIV 0.07% (n = 47), Syphilis 1.2% (n = 758) and malaria 0.3% (n = 218). Out of 57759 seronegative donors, thirty-four NAT-reactive samples were identified, with 3 cases of HCV, 31 cases of HBV, and Nil HIV cases. NAT yield of HBV was 1 in 1863 with an RR of 8.6 per million, followed by HCV with a NAT yield of 1 in 19253 and RR of 0.8 per million donations. NAT testing reduced RR for HBV by 48.9% and HCV by 94.5%. Conclusion Our study showed that NAT detected 34 out of 57759 cases initially missed by serological tests. The study suggests that the parallel use of serology and NAT screening of donated blood would be beneficial.

Adaptation of a Public-Private Partnership Model for the Implementation of Minipool Nucleic Acid Testing for Screening Routine Blood Donations and Assay Evaluation.

Background Nucleic acid amplification testing (NAT) for the screening of blood donations is known to improve blood safety. The decision to initiate NAT requires careful deliberation of infrastructure, skilled manpower, and financial resources. This report outlines the initiative of the Government of Odisha to implement NAT screening in government blood banks in the state of Odisha, India, through public–private partnership (PPP) and evaluates the incremental yield of minipool NAT screening over serology testing of blood donations. Methods Blood donations collected between June 2016 and September 2018 were initially screened for HBV (HBsAg), HCV (anti-HCV), and HIV (anti-HIV-1 and HIV-2) by ELISA, and syphilis and malaria. Sero-nonreactive donations were further screened in pools of six by Roche cobas TaqScreen MPX test version 2.0 (MPX2) NAT. Results On screening 3,39,472 blood donations, 1.34% seroreactive donations were detected. In all, 847 NAT-reactive donations (0.26%): 693 HBV, 58 HCV, and 96 HIV were detected. The NAT yields were 1:386 overall, 1:472 for HBV, 1:5642 for HCV, and 1:3409 for HIV. Conclusion NAT testing using the highly sensitive MPX2 assay leads to incremental detection of TTIs over serology. Implementation of NAT along with serological testing in blood centers all over India will be an important step towards providing safe blood. Our study not only highlights the benefits of minipool NAT testing but also presents a scalable PPP model that can serve as a template for application across other states.

The impact of nucleic acid testing to detect human immunodeficiency virus, hepatitis C virus, and hepatitis B virus yields\xa0from a single blood center in China with 10-years review

BackgroundSince 2010, the Blood Center of Zhejiang province, China, has conducted a pilot nucleic acid amplification testing (NAT) screening of blood donors for Hepatitis B virus (HBV), Hepatitis C virus (HCV), and Human immunodeficiency virus (HIV). This study aims to assess the results of NAT testing over 10 years to establish the effects and factors influencing NAT yields of HBV, HCV, and HIV.MethodsBlood donations from seven different blood services were screened for HBV DNA, HCV RNA, and HIV RNA using 6 mini pools (6MP) or individual donation (ID)-NAT method between August 1, 2010, and December 31, 2019, at the NAT centralized screening center. We compared 3 transcription-mediated amplification (TMA) assays and 2 polymerase chain reaction (PCR) assays. Further, HBV, HCV, and HIV NAT yields were calculated and donor characteristics and prevalence of HBV NAT yields analyzed. Donors with HCV and HIV NAT yield were also followed up.Results1916.31 per million donations were NAT screening positive overall. The NAT yields for HBV, HCV, HIV and non-discriminating reactive were 1062.90 per million, 0.97 per million, 1.45 per million, and 850.99 per million, respectively, which varied in the seven blood services and different years. HBV NAT yields were higher than those of HCV and HIV and varied across demographic groups. Risk factors included being male, old age, low education level, and first-time donors. We found no differences in NAT yields of HBV, HCV, and HIV between the 3 TMA and 2 PCR assays; nonetheless, statistically, significant differences were noted between the five assays.ConclusionIn summary, NAT screening in blood donations reduces the risk of transfusion-transmitted infections and shortens the window period for serological marker screening. Therefore, a sensitive NAT screening method, ID-NAT workflow, and recruitment of regular low-risk donors are critical for blood safety.

NATSpert ID TripleH: A novel individual donor multiplex nucleic acid amplification test to reduce risk of transfusion-transmitted infections: Two-year experience of a blood bank in central India

Background: In India serological screening is mandatory for all donated blood for hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) while Nucleic Acid Amplification Testing (NAT) is not a mandatory screening test. There is a risk of transfusion-transmitted infections (TTI) during window period using serology. Aims and Objectives: The aim of this study was to analyse NAT screening using an indigenously developed, Indian manufactured Individual Donor NAT (ID-NAT) and compare it with serology. Materials and Methods: All blood donations between June 2017-March 2019 were screened serologically for HBV, HCV and HIV at an Indian blood bank. Blood donations also underwent ID-NAT screening using the NATSpert ID TripleH detection assay based on real time PCR. The results were analysed to identify yield cases. Results: In the study, 30,772 blood donor samples were screened serologically out of which 214 were reactive. 30,558 serologically non-reactive blood donations and 77 randomly selected, serologically reactive blood donations were screened using NATSpert. Out of 30,635, 85 donor samples were reactive on the NATSpert which included 77 serology positive and 8 NAT yield cases. The NAT yield found was 2 each for HBV/HIV and 4 of HCV. Conclusion: The NATSpert ID TripleH offers a statistically significant advantage over EIA in ability to detect TTI in blood donors (P < 0.05, Fishers Exact Test). The NAT yield of 1:3829 was in line with other Indian studies. NATSpert assay will provide a significant improvement in blood safety and offer a cost benefit compared to the imported products.

Transfusion Transmissible Infections: Maximizing Donor Surveillance.

IntroductionThe World Health Organization (WHO) recommends that all blood transfusion services must screen donated blood for human immunodeficiency virus (HIV) one and two, hepatitis B, hepatitis C and syphilis. A mandatory screening for malaria is also warranted in malaria endemic areas. Our study aimed at analyzing the prevalence and different diagnostic methods of screening transfusion transmitted infections (TTIs) in replacement and voluntary, non-remunerated donors in the blood bank of a tertiary care hospital in Islamabad, Pakistan.MethodsThe cross-sectional, descriptive study was conducted on 30,470 blood donors from July 2015 to October 2017, in the blood bank of a 500-bed teaching hospital in Islamabad. Initially all blood donors were screened for HIV one, HIV two, hepatitis B and hepatitis C by serological testing. The seronegative samples were further tested by nucleic acid amplification test (NAT). Malaria was screened using immuno-chromatographic antigen-detection tests, while treponema pallidum was screened by electrochemiluminescence immunoassay to detect treponema pallidum (TP) antibodies. All infected blood and blood products were discarded and donors were contacted. The donors were deferred from blood donation according to WHO guidelines. They were also counselled and referred to the infectious diseases clinic. The collected data was analyzed on IBM's statistical package for the social sciences (SPSS) version 21.ResultsThe results revealed that amongst the 30,470 donors, 997 (3.27%) donors were found infected with one or more TTI while 29,473 (96.73%) donors were found safe. Individuals who tested positive on serology for hepatitis B were 322 (1.06%), hepatitis C were 392 (1.29%) and HIV were 49 (0.16%). The seronegative donors were tested by NAT. NAT on seronegative samples showed that 10 (0.03%) donors tested positive for hepatitis B virus deoxyribonucleic acid, while only three (0.01%) were positive for hepatitis C ribonucleic acid. No donor was found positive for HIV by NAT testing. Syphilis testing revealed a frequency of 228 (0.75%) positive results while only five (0.02%) donors were found infected with malaria.ConclusionThe results testify that standardized blood component screening can save transmission of infections through blood transfusion. They also establish the superiority of NAT screening over serological tests in decreasing the residual risk of transfusion transmitted infections.

Prevalence and characteristics of rectal chlamydia and gonorrhea cases among men who have sex with men after the introduction of nucleic acid amplification test screening at 2 Canadian sexually transmitted infection clinics.

We sought to determine the prevalence of rectal chlamydia and gonorrhea after the introduction of nucleic acid amplification tests for screening in men reporting receptive anal intercourse. The rectal chlamydia prevalence was 14.1% (95% confidence interval, 11.9-16.3), and the gonorrhea prevalence was 5.9% (95% confidence interval, 4.4-7.3). Most cases were positive only from the rectum.

Author Response: Reducing Infection Transmission in Solid Organ Transplantation Through Donor Nucleic Acid Testing: A Cost-Effectiveness Analysis

Author Response: Reducing Infection Transmission in Solid Organ Transplantation Through Donor Nucleic Acid Testing: A Cost-Effectiveness Analysis

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.

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

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

Screening Acute HIV Infections among Chinese Men Who Have Sex with Men from Voluntary Counseling &amp; Testing Centers

BackgroundRecent studies have shown the public health importance of identifying acute HIV infection (AHI) in the men who have sex with men (MSM) of China, which has a much higher risk of HIV transmission. However, cost-utility analyses to guide policy around AHI screening are lacking.Methodology/Principal FindingsAn open prospective cohort was recruited among MSM living in Liaoning Province, Northeast China. Blood samples and epidemiological information were collected every 10 weeks. Third-generation ELISA and rapid test were used for HIV antibody screening, western blot assay (WB) served for assay validation. Antibody negative specimens were tested with 24 mini-pool nucleic acid amplification testing (NAAT). Specimens with positive ELISA but negative or indeterminate WB results were tested with NAAT individually without mixing. A cost-utility analysis of NAAT screening was assessed. Among the 5,344 follow-up visits of 1,765 MSM in 22 months, HIV antibody tests detected 114 HIV chronic infections, 24 seroconverters and 21 antibody indeterminate cases. 29 acute HIV infections were detected with NAAT from 21 antibody indeterminate and 1,606 antibody negative cases. The HIV-1 prevalence and incidence density were 6.6% (95% CI: 5.5–7.9) and 7.1 (95% CI: 5.4–9.2)/100 person-years, respectively. With pooled NAAT and individual NAAT strategy, the cost of an HIV transmission averted was $1,480. The addition of NAAT after HIV antibody tests had a cost-utility ratio of $3,366 per gained quality-adjusted life year (QALY). The input-output ratio of NAAT was about 1∶16.9.Conclusions/SignificanceThe HIV infections among MSM continue to rise at alarming rates. Despite the rising cost, adding pooled NAAT to the HIV antibody screening significantly increases the identification of acute HIV infections in MSM. Early treatment and target-oriented publicity and education programs can be strengthened to decrease the risk of HIV transmission and to save medical resources in the long run.

Tissue donation and virus safety: more nucleic acid amplification testing is needed

In tissue and organ transplantation, it is of great importance to avoid the transmission of blood-borne viruses to the recipient. While serologic testing for anti-human immunodeficiency virus (HIV)-1 and -2, anti-hepatitis C virus (HCV), hepatitis B surface antigen (HBsAg), anti-hepatitis B core antigen (HBc), and Treponema pallidum infection is mandatory, there is until now in most countries no explicit demand for nucleic acid amplification testing (NAT) to detect HIV, hepatitis B virus (HBV), and HCV infection. After a review of reports in the literature on viral transmission events, tissue-specific issues, and manufacturing and inactivation procedures, we evaluated the significance of HIV, HCV, and HBV detection using NAT in donors of various types of tissues and compared our results with the experiences of blood banking organizations. There is a significant risk of HIV, HCV, and HBV transmission by musculoskeletal tissues because of their high blood content and the high donor-recipient ratio. If no effective virus inactivation procedure for musculoskeletal tissue is applied, donors should be screened using NAT for HIV, HCV, and HBV. Serologically screened cardiovascular tissue carries a very low risk of HIV, HCV, or HBV transmission. Nevertheless, because effective virus inactivation is impossible (retention of tissue morphology) and the donor-recipient ratio may be as high as 1:10, we concluded that NAT should be performed for HIV, HCV, and HBV as an additional safety measure. Although cornea allografts carry the lowest risk of transmitting HIV, HCV, and HBV owing to corneal physiology, morphology, and the epidemiology of corneal diseases, NAT for HCV should still be performed. If the NAT screening of a donor for HIV, HCV, and HBV is negative, quarantine storage of the donor tissue seems dispensable. In view of numerous synergistic effects with transfusion medicine, it would be advantageous for tissue banks to cooperate with blood bank laboratories in performing virological tests.

Evaluation of the Virus-elimination Efficacy of Nanofiltration (Viresolve NFP) for the Parvovirus B19 and Hepatitis A Virus

The safety of plasma derivatives has been reinforced since 1980s by variable pathogen inactivation or elimination techniques. Nucleic acid amplification test (NAT) for the source plasma has also been implemented worldwide. Recently nanofiltration has been used in some country for ensuring safety of plasma derivatives to eliminate non-enveloped viruses such as parvovirus B19 (B19V) and hepatitis A virus (HAV). We evaluated the efficacy of nanofiltration for the elimination of B19V and HAV. To verify the efficacy of nanofiltration, we adopted a 20 nm Viresolve NFP (Millipore, USA) in the scaling down (1:1,370) model of the antithrombin III production. As virus stock solutions, we used B19V reactive plasma and porcine parvovirus (PPV) and HAV obtained from cell culture. And 50% tissue culture infectious dose was consumed as infectious dose. The methods used to evaluate the virus-elimination efficacy were reverse-transcriptase polymerase chain reaction for B19V and the cytopathic effect calculation after filtration for PPV and HAV. B19V was not detected by RT-PCR in the filtered antithrombin III solutions with initial viral load of 6.42 x 10(5) IU/mL and 1.42 x 10(5) IU/mL before filtration. The virus-elimination efficacy of nanofiltration for PPV and HAV were > or = (3.32) and > or = (3.31), respectively. Nanofiltration would be an effective method for the elimination of B19V and HAV. It may be used as a substitute for NAT screening of these viruses in source plasma to ensure safety of plasma derivatives in Korea.

Regarding unexpected severe and life-threatening donor-transmitted viral infections and use of high-risk behavior donors

Regarding unexpected severe and life-threatening donor-transmitted viral infections and use of high-risk behavior donors

Performance of ORTHO® HCV core antigen and trak‐C™ assays for detection of viraemia in pre‐seroconversion plasma and whole blood donors

Logistics and cost of nucleic acid amplification testing (NAT) screening preclude its current use in many developing countries. Development of hepatitis C virus (HCV) core antigen assays offer an alternative to NAT. We evaluated two specimen populations to assess the sensitivity, relative to NAT, of the HCV core antigen (HCVcAg) ELISA (enzyme-linked immunosorbent assay) test system and the trak-C assay: (1) plasma donor HCV NAT-conversion panels and (2) cross-sectional whole blood donor NAT yield specimens. Differential sensitivities among NAT (NGI; Chiron/Gen-Probe) and both HCVcAg assays (Ortho-Clinical Diagnostics, Rochester, NY) were evaluated using: (1) 102 serial ramp-up phase specimens from 37 plasma donor NAT-conversion panels (Alpha Therapeutic/BioClinical Partners); and (2) 42 cross-sectional whole blood donor NAT yield specimens (confirmed RNA positive, antibody negative) plus 54 NAT false-positive specimens (American Red Cross). Viral load among the plasma donor NAT-conversion panels at the cutoffs for HCVcAg and trak-C assays were 32 000 copies/ml (95% confidence interval [CI] 8000-120 000) and 8000 copies/ml (95% CI: 2200-28 000), respectively. The mean (95% CI) difference in window period reduction compared to routine mini-pool NAT screening (estimated sensitivity 100 copies/ml) was delayed 5.2 days (2.2-7.6 days) for HCVcAg assay and 3.8 days (2.1-5.5 days) for the trak-C assay. Among the 42 NAT yield specimens, the HCVcAg assay detected 31 (74%) as core antigen-positive while the trak-C assay detected 37 (88%) as core antigen-positive. Viral loads for the five specimens not detected by the trak-C HCVcAg assay ranged from 100 to 7770 copies/ml. All 54 NAT false-positive specimens were non-reactive on both HCV core antigen assays. These data indicate that the trak-C assay has sensitivity approaching routine mini-pool NAT screening for the detection of seronegative HCV infection. In the absence of routine NAT screening for early HCV infection, the use of an HCV core antigen assay should be considered.

Hepatitis B NAT virus‐positive blood donors in the early and late stages of HBV infection: analyses of the window period and kinetics of HBV DNA

The Japanese Red Cross (JRC) carries out nucleic acid amplification testing (NAT) for hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus-1 (HIV-1) by using a multiplex (MPX) reagent. Screening is undertaken on serologically negative units. In this study we characterized HBV NAT-positive donations individually and analysed the window period and kinetics of HBV DNA, during acute infection, in follow-up studies. Two hundred and seventy-seven HBV DNA-positive donations have been identified in Japan since the introduction of NAT screening of 50-donation minipools. The viral loads and genotypes of these HBV DNA-positive donations were characterized. The doubling time and half-life of HBV was estimated from the data of 123 follow-up donors. The sensitivity of the NAT system (based on 50-donation minipools) was compared with the sensitivities of the enzyme immunoassay (EIA) and the chemiluminescence immunoassay (CLIA). Samples that were CLIA negative, but with > 10(4) copies/ml of HBV DNA, were analysed by sequencing the hepatitis B surface antigen (HBsAg) region. Out of 277 HBV NAT-positive samples, 125 (45%) were found to have an increasing viral load and 45 (16%) a decreasing viral load. Forty per cent of HBV NAT-positive samples with an increasing viral load, and 33% of those with a decreasing viral load, were negative when tested by using the CLIA. No mutations related to escape mutants were found in the samples that were CLIA negative but with HBV DNA loads of > 10(4) copies/ml. The median HBV doubling time was 2.6 days (n = 93, 1.3-15.2 days) and the half-life was 1.6 days (n = 55, 0.9-6.3 days). Some kinetic difference was observed between genotypes A and B. HBV NAT screening detected HBV DNA in both early (the so-called serological window period) and late stages of acute HBV infection.

Cost-effectiveness analysis of screening adolescent males for Chlamydia on admission to detention.

Chlamydia trachomatis infections can lead to serious and costly sequelae. Because chlamydia is most often asymptomatic, many infected youth do not seek testing. Entry to a detention system provides an opportunity to screen and treat many at-risk youth. GOAL The goal of this study was to determine the cost-effectiveness of screening male youth for chlamydia on entry to detention. Incremental cost-effectiveness of 3 chlamydia screening strategies was compared for a hypothetical cohort of 4000 male youth per year: 1) universal chlamydia screening using a urine-based nucleic acid amplification test (NAAT), 2) selective NAAT screening of urine leukocyte esterase (LE)-positive urines, and 3) no screening. The model incorporated programmatic costs of screening and treatment and medical cost savings from sequelae prevented in infected males and female partners. The analysis was conducted from the healthcare system perspective. Chlamydia prevalence in the sampled population of 594 was 4.8%, and the average number of female sexual partners/infected male was 1.6. Universal NAAT screening was the most cost-effective strategy, preventing 37 more cases of pelvic inflammatory disease (PID) and 3 more cases of epididymitis than selective screening and saving an additional 24,000 dollars. The analysis was sensitive to NAAT cost, LE sensitivity, rate of PID development, PID sequelae cost, and number of female partners. Universal screening remained the most cost saving for prevalence as low as 2.8% or higher. Universal chlamydia screening of adolescent males on entry to detention was the most cost-effective strategy. Savings are primarily the result of the prevention of PID in recent and future partners of index males. Screening detained male youth using a urine-based NAAT provides a public health opportunity to significantly reduce chlamydia infections in youth at risk for sexually transmitted diseases.

Should HBV DNA NAT replace HBsAg and/or anti-HBc screening of blood donors?

Prevention of transfusion-transmitted hepatitis B virus (HBV) has historically relied on serological screening of blood donors using progressively more sensitive HBsAg assays; in some countries anti-HBc assays have also been employed to detect chronic carriers with low-level viremia who lack detectable HBsAg. Nucleic acid amplification testing (NAT) for HCV and HIV has been successfully introduced to screen donors in many developed countries over the past several years; for logistical and cost reasons HCV/HIV NAT screening has been applied to mini-pools (MP) of eight to 96 donor specimens, with only minimal impact of MP dilutions on clinical sensitivity for interdiction of window period (WP) donations. In several countries (e.g., Japan and Germany), HBV NAT has been added to HIV/HCV MP-NAT blood donor screening with small incremental yields of HBsAg/anti-HBc-negative donations, and the major vendors of NAT systems (Roche and Chiron/Gen-Probe) have been developing triplex assays that include HBV DNA detection capacity without compromising HIV or HCV detection. Pooled specimen HBV NAT has also become the standard of practice for screening source plasma donors, with pressure to include HBV DNA detection as a required procedure for use of recovered plasma in manufacture of fractionated derivatives. However, there is controversy over the magnitude of the incremental yield and clinical benefit of HBV MP-NAT over serological screening strategies, as well as the impact of implementation of HBV NAT on need for retention of HBsAg and anti-HBc screening. This presentation will review recent modeled and empirical data on the value of HBV MP- and individual donation (ID)-NAT for detection of (1) pre-HBsAg WP units and (2) chronic anti-HBc-reactive carriers with undetectable HBsAg. The presentation will also review policy considerations and data that address the potential for discontinuation of either HBsAg or anti-HBc following implementation of HBV NAT. Finally it will address the cost effectiveness of incorporation of HBV DNA detection into HBV screening and NAT testing algorithms.

献血者におけるＨＩＶについての意識調査

In 1999, the number of donors with HIV antibodies was 63, giving a prevalence of 1.026per 100, 000 donations collected by the Japanese Red Cross Society Blood Centers. The current frequency is higher than would be expected from the prevalence rate of HIV in Japan. We conducted a questionnaire to determine blood donor understanding of HIV. The survey looked at responses anonymously from 676 apheresis donors who donated at 8 collection offices in Aichi Prefecture in mid-January, 2000. It indicated that almost all of them were really comprehensive and 27% of respondents supported the present policy of not letting donors know the results of their HIV tests. But a tiny fraction of repeated donors did not understand why they should not donate blood as a means of checking on HIV.To reduce the risk of transfusion-transmitted infection, nucleic acid amplification test screening for HIV, HBV and HCV was introduced for all donated blood in October 1999. However, based on the rapid spread of sexually transmitted diseases and drug abuse especially among younger people, it is essential for ensuring blood safety that adequate donor education be conducted along with various approaches to reduce blood-borne infection including HIV.