The prototypical UK blood donor, homophily and blood donation: Blood donors are like you, not me.

BACKGROUND AND OBJECTIVES: Homophily represents the extent to which people feel others are like them and encourages the uptake of activities they feel people like them do. Currently, there are no data on blood donor homophily with respect to (i) people's representation of the average prototypical UK blood donor and (ii) the degree of homophily with this prototype for current donors, non-donors, groups blood services wish to encourage (ethnic minorities), those who are now eligible following policy changes (e.g., men-who-have-sex-with-men: MSM) and recipients. We aim to fill these gaps in knowledge. MATERIALS AND METHODS: We surveyed the UK general population MSM, long-term blood recipients, current donors, non-donors and ethnic minorities (n = 785) to assess perceptions of the prototypical donor in terms of ethnicity, age, gender, social class, educational level and political ideology. Homophily was indexed with respect to age, gender and ethnicity. RESULTS: The prototypical UK blood donor is perceived as White, middle-aged, middle-class, college-level educated and left-wing. Current donors and MSM are more homophilous with this prototype, whereas recipients and ethnic minorities have the lowest homophily. Higher levels of homophily are associated with an increased likelihood of committing to donate. CONCLUSION: The prototype of the UK donor defined this as a White activity. This, in part, may explain why ethnic minorities are less likely to be donors. As well as traditional recruitment strategies, blood services need to consider broader structural changes such as the ethnic diversity of staff and co-designing donor spaces with local communities.

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.

An international review of the characteristics of viral nucleic acid-amplification testing (NAT) reveals a trend towards the use of smaller pool sizes and individual donation NAT.

BACKGROUND AND OBJECTIVES: Nucleic acid-amplification testing (NAT) is used for screening blood donations/donors for blood-borne viruses. We reviewed global viral NAT characteristics and NAT-yield confirmatory testing used by blood operators. MATERIALS AND METHODS: NAT characteristics and NAT-yield confirmatory testing used during 2019 was surveyed internationally by the International Society of Blood Transfusion Working Party Transfusion-Transmitted Infectious Diseases. Reported characteristics are presented herein. RESULTS: NAT was mainly performed under government mandate. Human immunodeficiency virus (HIV), hepatitis C virus (HCV) and hepatitis B virus (HBV) NAT was performed on all donors and donation types, while selective testing was reported for West Nile virus, hepatitis E virus (HEV), and Zika virus. Individual donation NAT was used for HIV, HCV and HBV by ~50% of responders, while HEV was screened in mini-pools by 83% of responders performing HEV NAT. Confirmatory testing for NAT-yield samples was generally performed by NAT on a sample from the same donation or by NAT and serology on samples from the same donation and a follow-up sample. CONCLUSION: In the last decade, there has been a trend towards use of smaller pool sizes or individual donation NAT. We captured characteristics of NAT internationally in 2019 and provide insights into confirmatory testing approaches used for NAT-yields, potentially benefitting blood operators seeking to implement NAT.

International review of blood donation nucleic acid amplification testing.

BACKGROUND AND OBJECTIVES: Nucleic acid amplification testing (NAT), in blood services context, is used for the detection of viral and parasite nucleic acids to reduce transfusion-transmitted infections. This project reviewed NAT for screening blood donations globally. MATERIALS AND METHODS: A survey on NAT usage, developed by the International Society of Blood Transfusion Working Party on Transfusion-transmitted Infectious Diseases (ISBT WP-TTID), was distributed through ISBT WP-TTID members. Data were analysed using descriptive statistics. RESULTS: Forty-three responses were received from 32 countries. Increased adoption of blood donation viral screening by NAT was observed over the past decade. NAT-positive donations were detected for all viruses tested in 2019 (proportion of donations positive by NAT were 0.0099% for human immunodeficiency virus [HIV], 0.0063% for hepatitis C virus [HCV], 0.0247% for hepatitis B virus [HBV], 0.0323% for hepatitis E virus [HEV], 0.0014% for West Nile virus [WNV] and 0.00005% for Zika virus [ZIKV]). Globally, over 3100 NAT-positive donations were identified as NAT yield or solely by NAT in 2019 and over 22,000 since the introduction of NAT, with HBV accounting for over half. NAT-positivity rate was higher in first-time donors for all viruses tested except WNV. During 2019, a small number of participants performed NAT for parasites (Trypanosoma cruzi, Babesia spp., Plasmodium spp.). CONCLUSION: This survey captures current use of blood donation NAT globally. There has been increased NAT usage over the last decade. It is clear that NAT contributes to improving blood transfusion safety globally; however, there is a need to overcome economic barriers for regions/countries not performing NAT.

Determining the strength of evidence for an association between sexual indicators and risk of acquiring HIV and sexulaly transmitted infections: Providing evidence for blood donation policy change.

In 2019 the For The Assessment Of Individualised Risk (FAIR) project began a review of UK blood donor selection policy to determine if a more individualised approach to donor selection could be safely implemented. An evidence base was required to inform selection policy to move from a population to a more individual based policy, specifically what sexual behaviours/indicators should be considered as screening questions to maintain the safety of the blood supply. Eight sexual behaviours/indicators were reviewed: history of bacterial sexually transmitted infections (STIs), chemsex, number of recent partners, condom use, type of sex, sexual health service (SHS) attendance, new sexual partner and exclusivity. We conducted searches in multiple databases to identify literature looking at the association between these behaviours/indicators and HIV/STI acquisition risk. A scoring system to determine strength of evidence was devised and applied to papers that passed screening. Key studies were identified which achieved the maximum score and more in-depth reviews were conducted for these. We identified 58 studies, including 17 key studies. Strong evidence was found linking a previous bacterial STI, chemsex and increasing numbers of sexual partners to acquisition risk. Condom use, type of sex and new partners were found to have some strength of evidence for this link. SHS attendance and exclusivity had minimal evidence. We recommended that the behaviours/indicators viewed as having strong or some strength of evidence should be considered as screening questions in a more individualised approach to donor selection criteria.

Communicating the move to individualized donor selection policy: Framing messages focused on recipients and safety.

BACKGROUND: Men-who-have-sex-with-men (MSM) have been deferred from donating blood. However, recent evidence supports the adoption of donor screening based on individuals' sexual behavior over population-based criteria. We explore how best to frame communications about adopting this change to minimize any potential negative consequences (e.g., reduced donor numbers). We examine the effectiveness of risk (emphasizing safety vs. emphasizing low risk), and focus (donor vs. recipient) frames on intentions to donate blood (approach) or feeling deterred from donating (avoid), and mechanisms linked to under-reporting sexual behavior. STUDY DESIGN AND METHODS: We conducted a 2 (risk frame: risk vs. safety) by 3 (focus: donor vs. recipient vs. both) between-subjects online experiment (n = 2677). The main outcomes were intentions to donate and feelings of being put-off/deterred from donating (both for self and others). We also assessed the extent that forgetting, embarrassment/shame, and question irrelevance were perceived to be associated with under-reporting sexual behavior. RESULTS: Frames that focused on safety or a recipient resulted in people reporting being less deterred from donating. Regardless of frame, people from ethnic minorities were more likely to feel deterred. Embarrassment/shame followed by forgetting and perceived irrelevance were the main reasons for under-reporting sexual behaviors, especially in ethnic minorities, and smartphones were perceived as an acceptable memory aid for sexual behavior. DISCUSSION: Blood services moving to an individualized policy should frame donor selection in terms of safety and/or a recipient focus, explore sensitivities in ethnic minority communities, consider ways to normalize reporting sexual behavior, and use smartphones as a memory aid.

Fulminant Transfusion-Associated Hepatitis E Virus Infection Despite Screening, England, 2016-2020.

In England, all blood donations are screened in pools of 24 by nucleic acid test (NAT) for hepatitis E virus (HEV) RNA. During 2016-2020, this screening successfully identified and intercepted 1,727 RNA-positive donations. However, review of previous donations from infected platelet donors identified 9 donations in which HEV RNA detection was missed, of which 2 resulted in confirmed transmission: 1 infection resolved with ribavirin treatment, and 1 proceeded to fatal multiorgan failure within a month from infection. Residual risk calculations predict that over the 5-year study period, HEV RNA detection was missed by minipool NAT in 12-23 platelet and 177-354 whole-blood donations, but transmission risk remains undetermined. Although screening has been able to largely eliminate infectious HEV from the blood supply in England, missed detection of low levels of HEV RNA in donated blood can lead to a severe, even fulminant, infection in recipients and could be prevented by more sensitive screening.

How do we decide how representative our donors are for public health surveillance?

BACKGROUND: Surveillance of blood donors is fundamental to safety of the blood supply. Such data can also be useful for public health policy but tend to be underutilized. When the COVID-19 pandemic arrived, blood centers around the world measured blood donor SARS-CoV-2 seroprevalence to inform public health policy. There is now a movement toward blood centers becoming more involved in public health research and surveillance post-pandemic. However, blood donors are a healthy population and not representative of all segments of the general population. In this article, we explain how blood centers can evaluate their donor base to understand which part of the general population they are representative of. STUDY DESIGN AND METHODS: Methodologic approaches for evaluating samples relative to the target population were reviewed. Blood donor data that are available to most blood centers were identified and application to assess representativeness of blood donors was evaluated. RESULTS: Key aspects of blood donor data to compare with general population data include donor selection criteria, health indicators, geography, and demographics. In some cases, statistical adjustment can improve representativeness. DISCUSSION: Comparing key blood donor data with corresponding general population data can define the subset of the general population for which a particular blood center's donors may be representative of. We suggest that donors are an ideal convenience population for surveillance of infectious agents which are frequently asymptomatic and main routes of transmission are not deferrable, for studying the natural history of disease in an initially well population, and for vaccination serology surveillance.

HIV residual risk in Canada for apheresis source plasma donation without deferral for men who have sex with men.

BACKGROUND AND OBJECTIVES: In Canada, men having sex with men (MSM) are deferred for 3 months from last sexual contact to reduce human immunodeficiency virus (HIV) risk to recipients. The aim of this paper was to model the Canadian residual risk of HIV-positive source plasma incorporating pathogen inactivation (PI) under no MSM deferral scenarios for apheresis plasma donations. MATERIALS AND METHODS: A combined Bayesian network (BN) and Monte Carlo approach were implemented to estimate the HIV residual risk under 3-month deferral compared with no deferral without quarantine scenarios for MSM donors. Models involve the stochastic generation of donation and its infection status based on its corresponding simulated donor profile. Viral load reduction conferred by PI used by source plasma fractionators was simulated. Model parameters were derived from Héma-Québec and Canadian Blood Services data, viral loads in a large sample of HIV-positive US blood donors, CSL Behring documentation and from published data. RESULTS: In the most likely scenario for the 3-month deferral model, there were 2.71 positive donations per 1,000,000 donations (95% confidence interval [CI] 2.63-2.78). For the no-deferral model, there were 3.01 positive donations per 1,000,000 donations (95% CI 2.94-3.09). For both scenarios, the risk of having an infectious pool was 0 in 300,000 pools (95% CI 0-0.0000123) after consideration of PI. CONCLUSION: Based on simulation results, there would be a negligible HIV residual risk associated with the removal of a time-based MSM deferral without quarantine for source plasma incorporating PI.

Current challenges of severe acute respiratory syndrome coronavirus 2 seroprevalence studies among blood donors: A scoping review.

BACKGROUND AND OBJECTIVES: Blood donors are increasingly being recognized as an informative resource for surveillance. We aimed to review severe acute respiratory syndrome coronavirus 2 seroprevalence studies conducted among blood donors to investigate methodological biases and provide guidance for future research. MATERIALS AND METHODS: We conducted a scoping review of peer-reviewed and preprint publications between January 2020 and January 2021. Two reviewers used standardized forms to extract seroprevalence estimates and data on methodology pertaining to population sampling, periodicity, assay characteristics, and antibody kinetics. National data on cumulative incidence and social distancing policies were extracted from publicly available sources and summarized. RESULTS: Thirty-three studies representing 1,323,307 blood donations from 20 countries worldwide were included (sample sizes ranged from 22 to 953,926 donations). The majority of the studies (79%) reported seroprevalence rates <10% (ranging from 0% to 76% [after adjusting for waning antibodies]). Overall, less than 1 in 5 studies reported standardized seroprevalence rates to reflect the demographics of the general population. Stratification by age and sex were most common (64% of studies), followed by region (48%). A total of 52% of studies reported seroprevalence at a single time point. Overall, 27 unique assay combinations were identified, 55% of studies used a single assay and only 39% adjusted seroprevalence rates for imperfect test characteristics. Among the nationally representative studies, case detection was most underrepresented in Kenya (1:1264). CONCLUSION: By the end of 2020, seroprevalence rates were far from reaching herd immunity. In addition to differences in community transmission and diverse public health policies, study designs and methodology were likely contributing factors to seroprevalence heterogeneity.

Trust and distrust: Identifying recruitment targets for ethnic minority blood donors.

BACKGROUND: We explore the role of trust, distrust, and the prevailing socio-political context to better understand why people from ethnic minority communities are less likely to be blood donors compared to people from White communities. Recruiting more ethnic minority donors will enhance representativeness, reduce inequality, and help meet the clinical need to increase the proportion of blood with Ro Kell antigen to treat Sickle Cell Disease (SCD). STUDY DESIGN AND METHODS: A 2 (donor-status: current donor; non-donors) by 4 (ethnicity: People from Asian, Black, Mixed and White ethnic backgrounds) quasi-experiment (N = 981) was conducted to examine perceptions of trust/distrust and their influence on willingness to donate blood, within the socio-political context of the Windrush scandal and Brexit. RESULTS: We identified five domains of trust ('National Health Service [NHS] and staff,' 'NHS Blood and Transplant,' 'outgroups,' 'individuals' and 'politics'), and a single domain of conditional distrust domain. Trust across all the domains was lower, and 'conditional distrust' higher for ethnic minorities. Trust in 'individuals' and 'NHSBT' predicted willingness to donate in non-donors from ethnic minorities and White non-donors, respectively. Concerns about the Windrush scandal were related to lower political trust. Viewing Brexit as 'positive for the UK' was related to lower trust across domains and reduced willingness to donate in White non-donors through its influence on reduced trust in NHSBT. CONCLUSION: Distinct domains of trust and distrust are identified, and targeting 'trust in others' through conditional cooperation is recommended as a strategy to increase donor numbers from ethnic minority communities.

Hepatitis B infections among blood donors in England between 2009 and 2018: Is an occult hepatitis B infection a risk for blood safety?

INTRODUCTION: Hepatitis B virus (HBV) is one of the most frequent infections identified in blood donors in England and represents an ongoing blood safety risk. We have analyzed markers of HBV infections in blood donors in England between 2009 and 2018 and used these to estimate the likelihood of non-detection of occult HBV infection (OBI). METHODS: We collected epidemiological, virological, and genotyping information on HBV cases identified in England, 2009-2018. The estimated risk of non-detection and likely transmission of OBI were compared to lookback and transfusion-transmitted infections surveillance data. RESULTS: Six-hundered and fifty-five HBV-infected blood donors were identified in England during the 10-year period; 598 chronic, 32 acute, and 25 occult HBV infections. However, most donors with chronic and occult infections were born in Eastern Europe, Africa, or Asia (451/544, 83% and 14/24, 58%); acute infections were largely seen in UK-born donors (19/28, 68%). Genotyping of 266 HBV-positive samples revealed five genotypes (A-E), reflecting ethnicity and country of birth. Most OBIs were identified in repeat donors (19/25); lookback data identified a transmission rate of 8.3%. It is estimated that at least 13 potentially infectious donations from donors with OBI remain undetected annually, equating to an overall residual transmission risk of 3.1 per million donations using our current screening strategy of HBsAg screening with HBV nucleic acid testing (NAT) in pools of 24. CONCLUSIONS: OBI accounted for the majority of the HBV residual risk in England. Further cost-benefit analysis is required to estimate if our current HBV screening strategy should be changed.

Blood donation by men who have sex with men: using evidence to change policy.

BACKGROUND: In 2011 in the United Kingdom (UK), excluding Northern Ireland, the deferral of men who have sex with men (MSM) changed from lifetime to 12 months. We describe MSM who donated before and after this to inform further policy reviews. MATERIALS AND METHODS: Characteristics and sexual behaviours of donors identifying as male from routine surveillance are described. Rates of infections are compared pre- and post-implementation of a 12-month deferral. Donors are compared with screen negative male donors responding to a large-scale survey during 2013/2014. RESULTS: Comparing the five years pre- and post-change, the rate of confirmed positives for markers of HBV, HCV, HIV and syphilis decreased by 6·9% from 14·1 to 13·1/100 000 donations. The rate of recent infections was unchanged (1·72/100 000). Of 22 776 survey responses identifying as male, MSM disclosed sex between men over 12 months ago giving 99·35% compliance among male donors. Two-thirds of the 72 non-compliant MSM reported one to two partners and one-third had no new partners within 12 months. The most commonly reported reason for non-compliance from MSM both positive and negative for infection was 'not important to declare' (37·2% and 40·7%). Test seeking was rare (9·3% and 2·1%). CONCLUSION: Compliance with the 12-month MSM deferral policy was very high. The very low rates of infections post-change demonstrated the effectiveness of the policy. These data were an important part of the 2017 review of all sexual behaviour deferrals.

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.

Re-assessing the risk of undetected HBV, HCV and HIV in deceased tissue and living surgical bone donors in England.

Testing of living surgical bone and deceased tissue donors by NHS Blood and Transplant (NHSBT) has included individual donation (ID) nucleic acid testing (NAT) for HBV, HCV and HIV since 2008. Here, the well-established window period methodology was used to estimate residual risk (RR). Prevalence of viral markers was calculated among both tissue donor populations. Incidence was derived by adjusting incidence among new blood donors by the prevalence ratio for tissue and new blood donors. Residual risk (RR) was calculated as the product of incidence and duration of WP for single donor HBV NAT at 0.058 years (21 days), HCV NAT at 0.008 years (3 days) and HIV NAT at 0.014 (5 days). Between 2013 and 2017, 7886 living surgical bone donors were tested, 16 were positive for markers of HBV, HCV and HIV. HCV had the highest prevalence at 114/100,000 donors. Incidence and RR was highest for HBV at 3.55/100,000-person years and 0.32/100,000 donors (95% CI 0.11/100,000-1.42/100,000). Among 9751 deceased tissue donors tested, 22 were positive for viral markers. HBV had highest prevalence at 174/100,000 donors, and the highest incidence and RR at 8.12/100,000 person years and 0.74/100,000 donors (95% CI 0.08/100,000-2.99/100,000). Using ID NAT, RR of not detecting a HBV, HCV and HIV WP donation among tissue donors is less than 1/100,000 donors. These estimates provide a good starting point for discussing potential risks of viral transmission through tissue transplant with patients.

A typology of blood donor motivations.

BACKGROUND: Although the need for whole blood is declining, so too are the number of first-time and repeat blood donors. To develop new recruitment and retention strategies, therefore, we need to draw on as wide a variation in blood donor motivations as possible. The primary aim of this study is to draw on a large survey of donors to develop a broad, theoretically instantiated typology of donor motivations to identify new and less common, yet practically important, motivations that have not been previously reported. STUDY DESIGN AND METHODS: Using data from the UK Blood Donor Survey run by NHS Blood and Transplant/Public Health England Epidemiology Unit (N = 61 123 donors), we analyze fixed (N = 52 225) and free (N = 8867) responses to develop a more comprehensive typology of blood donor motivations based on theories from the biology, psychology, philosophy, economics, and sociology of altruism. RESULTS: We identified 54 motivations, including a number of newly identified motivations, for blood donations which we organized into 12 superordinate categories (eg, "inspiration via moral elevation," "perceived social closeness," and "fungibility of donations"). These are linked to intervention suggestions such as donating blood in memoriam or donating blood as an alternative to other charitable acts. CONCLUSION: We present the most comprehensive account of blood donor motivations to-date. This work also offers a structure for coding free-text responses, developing motivational measures, and identifying tangible interventions. Thus, we feel that this is a valuable resource for blood donor researchers, marketers, and policy makers.

What are blood donors telling us about injecting drug use?

BACKGROUND AND OBJECTIVES: Injecting drug use (IDU), a permanent deferral for blood donors, was included in a review of donor selection criteria completed in 2017. Here, we describe what is known about IDU in blood donors in the United Kingdom (UK). MATERIALS AND METHODS: Data were obtained from routine surveillance of donation testing and confirmed positive donors and a 2013/2014 UK survey of behaviour and compliance in screen-negative donors. RESULTS: Between 2009 and 2018, of 22 UK million donations screened, IDU was self-reported at the post-test discussion in 5% (86/1777) of donors with confirmed positive donations. Recent injecting within 12 months was reported in 8 HCV-positive donors, but only in 1/14 donors where it was clear HCV infection had been acquired in the previous 12 months. Of 65 439 survey responders, 25 reported IDU, which when weighted to the donor population gave 99·95% compliance. Most of the 111 donors reporting IDU felt it was not important to their donation, mainly because their injecting was in the past, while three HCV-positive recent injectors reported not sharing needles so presumably felt safe to donate. CONCLUSION: Compliance with the permanent deferral appeared extremely high with low levels of injecting reported by donors, mainly in the past. This agreed with the low-incident HCV infection observed in UK donors. These data contributed to a recommendation to reduce the deferral to 1 year. Ways of improving compliance in those few donors at current increased risk of infection need to be investigated.

HIV residual risk in Canada under a three-month deferral for men who have sex with men.

BACKGROUND AND OBJECTIVES: In Canada, the deferral for men who have sex with men (MSM) was decreased from a permanent deferral to a 5-year then a 12-month deferral. Current HIV testing can detect an HIV infection in donated blood within 2 weeks of exposure; thus, a 12-month deferral may be unnecessarily restrictive. We aimed to estimate the residual risk of HIV if the deferral were further decreased to 3 months. MATERIALS AND METHODS: Using a deterministic model with stochastic Monte Carlo simulation, residual risk of HIV was the sum of testing error, assay sensitivity and window-period risks. Data inputs were estimated from donor surveillance, donor surveys and published data. Residual risk was modelled at baseline and using three scenarios: (1) most likely - non-compliance, HIV prevalence and incidence rates of MSM are unchanged; (2) optimistic - non-compliance improves by 50%; and (3) pessimistic - non-compliance, HIV prevalence and incidence rates of MSM all double. RESULTS: HIV residual risk at baseline was 1 in 36·0 million donations (95% CI 1 in 1 504 907 million, 10·5 million); in the most likely scenario 1 in 34·2 million (1 in 225 534 million, 8·7 million); in the optimistic scenario 1 in 36·0 million (1 in 282 618 million, 9·5 million); in the pessimistic scenario 1 in 16·7 million (1 in 39 469 million, 6·0 million). All confidence intervals overlapped. CONCLUSION: With very low modelled risk under a 12-month deferral, the additional risk with a 3-month deferral is very low. This is true even with a pessimistic scenario.

Changing the deferral for men who have sex with men - an improved model to estimate HIV residual risk.

BACKGROUND AND OBJECTIVES: Eight published studies modelled the impact of changing from a lifetime to time-limited deferral for men who have sex with men (MSM); each predicted greater risk impact than has been observed. This study uses these previous efforts to develop an 'optimized' model to inform future changes to MSM deferrals. MATERIALS AND METHODS: HIV residual risk was calculated using observed HIV incidence/prevalence prior to the change in MSM deferral, then with the additional MSM expected under a 12-month deferral for five compliance scenarios, and finally using data observed after implementation of the deferral. Monte Carlo simulation calculated 95% confidence intervals (CI). RESULTS: The architecture of reviewed models was sound, and two were selected for combination into the optimized model. HIV risk estimated by this in the UK under MSM lifetime deferral was 0·102 (95% CI: 0·050-0·172) per million. The model predicted from a 27·8% decrease to a 47·6% increase depending upon compliance pre-implementation of the 12-month deferral. A decrease of 0·9% was observed post-implementation. For Canada, HIV risk under a 5-year deferral was 0·050 (95% CI: 0·00003-0·122) per million. Pre-implementation of the 12-month deferral, the model predicted from 30·2% decrease to 10-fold increase. A decrease of 47·0% was observed after implementation. CONCLUSION: The optimized model predicted HIV risk under 12-month MSM deferral in UK and Canada would remain low, and this was confirmed post-implementation. While the model is adaptable to other deferral scenarios, improved data quality would improve precision, particularly estimates of incidence in individuals likely to donate.

Infections and associated behaviors among deceased organ donors: Informing the assessment of risk.

BACKGROUND: For infectious disease risk assessment among deceased organ donors, pre-donation clinical, microbiological, and behavioral information are reviewed; however, uncertainty may arise due to false negative screening results of recently acquired infections. METHOD: The burden of hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV), and residual risks (RR) of undetected virus was estimated, with the impact of more sensitive screening. RESULTS: For United Kingdom potential deceased organ donors between 2010 and 2014, prevalence of HBsAg was 0.1%, HIV 0.06% and HCV 0.9%, increasing to 25.7% in people who injected drugs (PWID). Incidence, derived from new blood donors, was multiplied by duration of screening assay window periods to give RR per 100 000 donors as 0.43 (95% confidence interval [CI] 0.03-3.99) for HBV, 0.08 (95% CI 0.02-0.21) for HIV, and 5.96 (95% CI 0.82-37.89) for HCV. For PWID, HCV RR was 163.3 (95% CI 22.8-1107.8) compared to 2.76 (95% CI 0.35-17.36) for non-PWID. RR decreased significantly with nucleic acid testing (NAT), and, for HCV, antigen testing had a similar impact. CONCLUSION: While the burden of HCV risk lies within PWID, these are in small numbers therefore few HCV antigen or NAT tests would be needed to more accurately assess risk.