The high prevalence of occult hepatitis B infections among the partners of chronically infected HBV blood donors emphasizes the potential residual risk to blood safety.

A small percentage of couples who regularly donated blood in China tested positive for HBsAg. Although it is well known that blood donors can acquire hepatitis B virus (HBV) infection from a chronically infected sexual partner, the prevalence of occult hepatitis B infections (OBIs) among blood donations from partners of HBV-infected chronically infected spouses and the risk to blood safety remain poorly understood. Among 212 763 blood donors, 54 pairs of couples (108 donations) were enrolled because one partner tested positive for HBsAg. Several molecular and serological examinations were conducted. The origin of HBV transmission between sexual partners was investigated further. Also evaluated was the potential risk of HBV infection with OBIs. We identified 10 (10/54, 18.6%) sexual partners of chronically infected HBV donors who were positive for HBV DNA, including five samples (9.3%) with OBIs, of which 3 (3/54, 5.6%, 1 in 70 921 donations) passed the routine blood screening tests. Seven of the 10 HBV-DNA-positive couples contracted the virus possibly through sexual or close contact. Among infected couples, immune escape mutations were observed. A high prevalence of OBIs was found among the partners of chronically infected HBV blood donors, posing a potential threat to blood safety.

Investigation of Bacterial Infections Among Patients Treated With Umbilical Cord Blood-Derived Products Marketed as Stem Cell Therapies.

Importance: The number of clinics marketing stem cell products for joint diseases, chronic pain, and most recently, COVID-19, has increased despite warnings from the US Food and Drug Administration that stem cell products for these and other indications have not been proven safe or effective. Objective: To examine bacterial infections in 20 patients who received umbilical cord blood-derived products marketed as stem cell treatment. Design, Setting, and Participants: This case series is a national public health investigation including case-finding, medical record review and abstraction, and laboratory investigation, including sterility testing of products and whole-genome sequencing of patient and product isolates. Participants included patients who developed bacterial infections following administration of umbilical cord blood-derived products marketed as stem cell treatment during August 2017 to September 2018. Data analysis was performed from March 2019 to September 2021. Exposures: Umbilical cord blood-derived products marketed as stem cell treatment. Main Outcomes and Measures: Data were collected on patient infections and exposures. The Centers for Disease Control and Prevention performed sterility testing on undistributed and distributed vials of product marketed as stem cell treatment and performed whole-genome sequencing to compare patient and product bacterial isolates. Results: Culture-confirmed bacterial infections were identified in 20 patients (median [range] age, 63 [2-89] years; 13 male patients [65%]) from 8 US states who sought stem cell treatment for conditions including pain, osteoarthritis, rheumatoid arthritis, and injury; all but 1 required hospitalization. The most frequently isolated bacteria from patients with infections were common enteric species, including Escherichia coli (14 patients) and Enterobacter cloacae (7 patients). Of unopened, undistributed products sampled for testing, 65% (22 of 34 vials) were contaminated with at least 1 of 16 bacterial species, mostly enteric. A patient isolate from Arizona matched isolates obtained from products administered to patients in Florida, and patient isolates from Texas matched undistributed product sent from the company in California. Conclusions and Relevance: Unapproved stem cell products can expose patients to serious risks without proven benefit. Sequencing results suggest a common source of extensive contamination, likely occurring during the processing of cord blood into product. Patients and health care practitioners who are considering the use of unapproved products marketed as stem cell treatment should be aware of their unproven benefits and potential risks, including serious infections.

Safe blood supply in sub-Saharan Africa: challenges and opportunities.

The low recruitment and retention of blood donors in sub-Saharan Africa is a grave concern for blood transfusion services in the region. This problem is exacerbated by factors such as a high prevalence of transfusion-transmissible infections and anaemia, over-reliance on family replacement donors, resource constraints, and poor communication with the public. To improve blood safety and availability, innovative intervention strategies must be developed and implemented. The primary objective of this Series paper is to discuss the available evidence in the region and to provide recommendations on how to improve safe blood supply in sub-Saharan Africa. These recommendations include a call for renewed attention to donor recruitment in blood transfusion centres, a consistent and structured educational intervention, the development and adherence to national policies on blood donor selection with focus on voluntary donations, and comprehensive screening of donations for transfusion-transmissible infections. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

A forecasting model to estimate the drop in blood supplies during the SARS-CoV-2 pandemic in Italy.

OBJECTIVES: To estimate the number of actually Severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) infected blood donors applying a statistical forecasting model. BACKGROUND: Following the outbreak of the SARS-CoV-2 epidemic, a drop in blood donation has been observed. It is crucial to determine the actual number of potential SARS-CoV-2-positive donors to define the measures and ensure adequate blood supply. METHODS: The cumulative incidence of SARS-CoV-2 positivity, calculated on the general population, was applied to the donor population by estimating the number of positive subjects. The calculation model was validated by the linear interpolation method. The number of blood units actually discarded based on post-donation information was also taken into account. RESULTS: Three months after the outbreak, 5322 donors were estimated to be positive for SARS-CoV-2 and were therefore potentially excluded from donation. A total of units of blood components were discarded following post donation information. The estimated number of donors deceased (180) and the number of clinically recovered individuals in the same period was also considered. CONCLUSION: This forecasting model can be used to obtain information on blood donors' involvement during future SARS-CoV-2 outbreaks, especially in case of changes concerning epidemiology, incidence by age bracket and geographical distribution and also for new outbreaks of emerging viruses.

New blood donors in times of crisis: Increased donation willingness, particularly among people at high risk for attracting SARS-CoV-2.

BACKGROUND: Traditionally, during crises the number of new blood donors increases. However, the current coronavirus disease 2019 (COVID-19) pandemic created additional barriers to donate due to governmental prevention measures and increased personal health risks. In this report, we examined how the pandemic affected new donor registrations in the Netherlands, especially among groups with higher risk profiles for severe COVID-19. Additionally, we explored the role of media for blood donation and new donor registrations. STUDY DESIGN AND METHODS: We analyzed new donor registrations and attention for blood donation in newspapers and on social media from January until May 2020, in comparison to the same period in 2017 to 2019. RESULTS: After the introduction of nationwide prevention measures, several peaks in new donor registrations occurred, which coincided with peaks in media attention. Interestingly, people with a higher risk profile for COVID-19 (e.g., due to age or region of residence) were overrepresented among new registrants. DISCUSSION: In sum, the first peak of the current pandemic has led to increased new blood donor registrations, despite the associated increased health risks. Time and future studies will have to tell whether these new donors are one-off 'pandemic' donors or if they will become regular, loyal donors.

Missed irradiation of cellular blood components for vulnerable patients: Insights from 10 years of SHOT data.

BACKGROUND: Irradiation of cellular blood components is recommended for patients at risk of transfusion-associated graft-vs-host disease (TA-GvHD). Prestorage leucodepletion (LD) of blood components is standard in the UK since 1999. STUDY DESIGN AND METHODS: Analysis of 10 years' reports from UK national hemovigilance scheme, Serious Hazards of Transfusion (2010-2019), where patients failed to receive irradiated components when indicated according to British Society for Haematology guidelines (2011). RESULTS: There were 956 incidents of failure to receive irradiated components all due to errors. One hundred and seventy two incidents were excluded from analysis, 125 of 172 (72.7%) because of missing essential information. No cases of TA-GvHD were reported in this cohort. The 784 patients received 2809 components (number unknown for 67 incidents). Most failures occurred in patients treated with purine analogues (365) or alemtuzumab (69), or with a history of Hodgkin lymphoma (HL) (192). Together these make up 626 of 784 (79.9%). Poor communication is an important cause of errors. CONCLUSION: Leucodepletion appears to reduce the risk for TA-GvHD. None of 12 cases of TA-GvHD reported to SHOT prior to introduction of LD occurred in patients with conditions recommended for irradiated components by current guidelines. Irradiation indefinitely for all stages of HL is not based on good evidence and is a difficult guideline to follow. Further research on long-term immune function in HL is required. Variation between different national guidelines reflects the very limited evidence.

Maintaining adequate donations and a sustainable blood supply: Lessons learned.

BACKGROUND: The availability of a safe blood supply is a key component of transfusion medicine. A decade of decreased blood use, decreased payment for products, and a dwindling donor base have placed the sustainability of the US blood supply at risk. STUDY DESIGN AND METHODS: A literature review was performed for blood center (BC) and hospital disaster management, chronically transfusion-dependent diseases, and appropriate use of group O-negative red blood cells (RBCs), and the Choosing Wisely campaign. The aim was to identify current practice and to make recommendations for BC and hospital actions. RESULTS: While BCs are better prepared to handle disasters than after the 9/11 attacks, messaging to the public remains difficult, as donors often do not realize that blood transfused during a disaster was likely collected before the event. BCs and transfusion services should participate in drafting disaster response plans. Hospitals should maintain inventories adequate for patients in the event supply is disrupted. Providing specialty products for transfusion-dependent patients can strain collections, lead to increased use of group O RBCs, and create logistical inventory challenges for hospitals. The AABB Choosing Wisely initiative addresses overuse of blood components to optimally use this precious resource. Group O-negative RBCs should be transfused only to patients who truly need them. CONCLUSIONS: Collecting and maintaining a blood supply robust enough to handle disasters and transfusion-dependent patients in need of specialty products is challenging. Collaboration of all parties should help to optimize resources, ensure appropriate collections, improve patient care, and ultimately result in a robust, sustainable blood supply.

Emergency response to COVID-19 epidemic: One Chinese blood centre's experience.

OBJECTIVE: The COVID-19 epidemic has caused a significant global social and economic impact since December 2019. The objective of this study was to demonstrate the emergency response of a Chinese blood centre on maintaining both the safety and the sufficiency of blood supply during large, emerging, infectious epidemics. MATERIALS AND METHODS: Early on in the outbreak of COVID-19, the Chengdu Blood Center developed strategies and implemented a series of measures, including enhanced recruitment efforts, addition of new donation deferral criteria and notification after donation, optimisation of donor experience, development and implementation of a new coronavirus nucleic acid detection technology platform for blood screening and screening all donations for SARS-CoV-2 RNA to maximumly protect the safety of blood supply during a time of unclear risk. RESULTS: Starting on February 20, the immediate satisfaction rate of blood product orders in Chengdu city's clinical settings reached 100%, and there was no case of blood transfusion infection. CONCLUSION: The recent experience during the outbreak of SARS-CoV-2 reminded us that improvement in the areas of national and international collaborative programmes for dealing with blood availability and safety concerns during early stages of a disaster and regional and national mechanisms for timely communication with the general public on behalf of blood services should help to better prepare us for future disasters.

Compliance and attitudes of blood donors following transitioning from permanent to 12-month deferral of men who have sex with men in Hong Kong.

BACKGROUND AND OBJECTIVES: Blood safety hinges not just on the scientific rationale for deferral period but potential donors' compliance with the prevailing policy. This study aimed to investigate donors' awareness, attitudes and compliance with the two-phased policy implementation of time-limited deferral for men who have sex with men (MSM) in Hong Kong. MATERIALS AND METHODS: Three rounds of questionnaire survey were conducted between July 2017 and June 2019 covering the periods of pre-implementation (Round A), post-implementation without and with pre-donation questionnaire revision (Round B and C). Chi-square test and multivariable regression analysis were performed. RESULTS: Of 3085 donors recruited, 968, 1036 and 1081 completed the surveys in Round A, B and C, respectively. The non-compliance rate of MSM remained stable at 0·6% (3/497), 0·4% (2/551) and 0·5% (3/587) among male donors in Round A, B and C, respectively. Two MSM donors from Round C complying with the prevailing policy were identified. About two-thirds (60·7%) of respondents from Round B and C were unaware of the policy change. Overall, over 80% were either neutral or positive about the change. CONCLUSION: Our study showed a consistently low non-compliance rate of MSM over the three periods. The generally high level of acceptance of time-limited deferral among donors lends support to science-based policy development to protect blood safety. The identification of compliant MSM donors suggests that the 12-month deferral is effective and acceptable to MSM. With a deferral period far exceeding the window period, it is a step towards a more equitable policy.

The current state of the platelet supply in the US and proposed options to decrease the risk of critical shortages.

Due to circumstances such as increased demand and an aging donor pool, the likelihood of critical platelet shortages is increasing. The platelet supply could be improved through the expansion of the donor pool, the identification and sustained utilization of high-quality donors, and changes in component processing and storage that result in a longer platelet shelf-life. Refrigerated platelets, stored at 1° to 6°C, have the potential to improve patient safety by decreasing the risk of bacterial contamination while concurrently allowing for a longer storage period (eg, 14 days) and improved hemostatic effectiveness in actively bleeding patients. An approach utilizing remuneration of apheresis platelet donors combined with pathogen reduction of the platelet components could be used as a means to increase the donor pool and identify and sustain safe, reliable, high-quality donors. Remuneration might provide an incentive for underutilized populations (eg, individuals <30 years old) to enter the apheresis platelet donor population resulting in a significant expansion of the platelet donor pool. Over time, approaches such as the use of refrigerated platelets, platelet donor remuneration, and the application of pathogen reduction technology, might serve to attract a large, reliable, and safe donor base that provides platelet collections with high yields, longer shelf-lives and, excellent hemostatic function.

Bacterial contamination and septic transfusion reaction rates associated with platelet components before and after introduction of primary culture: experience at a US Academic Medical Center 1991 through 2017.

BACKGROUND: The high incidence of septic transfusion reactions (STRs) led to testing being mandated by AABB from 2004. This was implemented by primary culture of single-donor apheresis platelets (APs) from 2004 and prestorage pooled platelets (PSPPs) from 2007. STUDY DESIGN/METHODS: Platelet (PLT) aliquots were cultured at issue and transfusion reactions evaluated at our hospital. Bacterial contamination and STR rates (shown as rates per million transfusions in Results) were evaluated before and after introduction of primary culture by blood centers that used a microbial detection system (BacT/ALERT, bioMerieux) or enhanced bacterial detection system (eBDS, Haemonetics). RESULTS: A total of 28,457 PLTs were cultured during pre-primary culture periods (44.7% APs; 55.3% at-issue pooled PLTs [AIPPs]) and 97,595 during post-primary culture periods (79.3% APs; 20.7% PSPPs). Forty-three contaminated units were identified in preculture and 34 in postculture periods (rates, 1511 vs. 348; p < 0.0001). Contamination rates of APs were significantly lower than AIPPs in the preculture (393 vs. 2415; p < 0.0001) but not postculture period compared to PSPPs (387 vs. 198; p = 0.9). STR rates (79 vs. 90; p = 0.98) were unchanged with APs but decreased considerably with pooled PLTs (826 vs. 50; p = 0.0006). Contamination (299 vs. 324; p = 0.84) and STR rates (25 vs. 116; p = 0.22) were similar for PLTs tested by BacT/ALERT and eBDS primary culture methods. A change in donor skin preparation method in 2012 was associated with decreased contamination and STR rates. CONCLUSION: Primary culture significantly reduced bacterial contamination and STR associated with pooled but not AP PLTs. Measures such as secondary testing near time of use or pathogen reduction are needed to further reduce STRs.

Transfusion-associated adverse events and implementation of blood safety measures - findings from the 2017 National Blood Collection and Utilization Survey.

BACKGROUND: Serious transfusion-associated adverse events are rare in the United States. To enhance blood safety, various measures have been developed. With use of data from the 2017 National Blood Collection and Utilization Survey (NBCUS), we describe the rate of transfusion-associated adverse events and the implementation of specific blood safety measures. STUDY DESIGN AND METHODS: Data from the 2017 NBCUS were used with comparison to already published estimates from 2015. Survey weighting and imputation were used to obtain national estimates of transfusion-associated adverse events, and the number of units treated with pathogen reduction technology (PRT), screened for Babesia, and leukoreduced. RESULTS: The rate of transfusion-associated adverse events requiring any diagnostic or therapeutic interventions was stable (275 reactions per 100,000 transfusions in 2015 and 282 reactions per 100,000 transfusions in 2017). In 2017 among US blood collection centers, 16 of 141 (11.3%) reported screening units for Babesia and 28 of 144 (19.4%) reported PRT implementation; 138 of 2279 (6.1%) hospitals reported transfusing PRT-treated platelets. In 2017, 134 of 2336 (5.7%) hospitals reported performing secondary bacterial testing of platelets (50,922 culture-based and 63,220 rapid immunoassay tests); in 2015, 71 of 1877 (3.8%) hospitals performed secondary testing (87,155 culture-based and 21,779 rapid immunoassay tests). Nearly all whole blood/red blood cell units and platelet units were leukoreduced. CONCLUSIONS: Besides leukoreduction, implementation of most blood safety measures reported in this study remains low. Nationally, hospitals might be shifting from culture-based secondary bacterial testing to rapid immunoassays.

A review of blood usage and wastage in a tertiary heart center.

Background/Objectives: Blood is a vital resource that its utilization is ever increasing throughout the world and blood wastage is a global challenge that needs to be controlled. Most blood resources are used during complications of pregnancy, trauma, severe childhood anemia, gynecology, cancers, surgery, hematology disorders, and chronic diseases. Units that are expired, broken bags, returning the blood unit after 30 min, blood clotted units, etc., which are due to lack of awareness may result in the wastage of blood products. The objective of this study is to analyze the usage and wastage of blood and its products in Mazandaran heart center.Methods: In this retrospective study, the survey was carried out on the data that were obtained from Mazandaran heart center of Sari, Iran during 2012-2017. Data included details of usage and wastage on blood and its product units. MS Excel 2016 and SPSS 16.0 were used in analysis and diagrams.Results: A total of 35,686 blood units were consumed, which included 55.7% packed red blood cells (PRBCs), 33.9% platelets (Plts), 8.9% fresh-frozen-plasma (FFP), and 8.9% cryoprecipitates. Moreover, 823 blood units including 41.4% FFP, 37.2% PRBCs, and 21.4% Plts were wasted mostly because of inappropriate order (70.6%). Cross-match to transfusion ratio was 1.13. The intensive care unit reported the highest level of blood intake by 45.0%. The blood group O+ was the most frequent by 34.8%. In addition, blood wastage has decreased over study period by approximately 10.0%.Conclusion: Our study showed not only the increasing pattern of blood usage but also the dropping pattern of blood wastage due to hemovigilance performance and additional training in our healthcare center. We found that the main reason for the blood wastage in this center is an excessive order of blood units.

The Potential Impact of Chikungunya Virus Outbreaks on Blood Transfusion.

Chikungunya virus (CHIKV) is responsible for large periodic epidemics in both endemic and nonendemic areas where competent mosquitoes are present. Transmission of CHIKV by transfusion during explosive outbreaks has never been documented, and the true impact of CHIKV infection on blood transfusion during an outbreak is unknown. Considerations include not only transfusions in the active outbreak areas but also returning travelers to nonendemic areas. Because there are no documented cases of transfusion-transmitted CHIKV, there are no standard guidelines regarding transfusion policies during a chikungunya fever outbreak. We review current information from studies during outbreaks with the goal of estimating the potential effect of different blood safety interventions (eg, querying donors for possible CHIKV exposure, chikungunya fever-related symptoms, screening for CHIKV RNA).

The global need and availability of blood products: a modelling study.

BACKGROUND: Blood transfusions are an important resource of every health-care system, with often limited supply in low-income and middle-income countries; however, the degree of unmet need for blood transfusions is often unknown. We therefore aimed to estimate the blood transfusion need and supply at national level to determine gaps in transfusion services globally. METHODS: We did a modelling study involving 195 countries and territories. We used blood component preparation data from 2011-13 to estimate blood availability for 180 (92%) of 195 countries from the WHO Global Status Report on Blood Safety and Availability. We calculated disease-specific transfusion needs per prevalent case for 20 causes in the USA using the National (Nationwide) Inpatient Sample dataset between the years 2000 and 2014, and the State Inpatient Databases between 2003 and 2007 from the Healthcare Cost and Utilization Project. Using prevalence estimates for the USA from the Global Burden of Disease (GBD) 2017 study, we estimated the ideal disease specific-transfusion rate as the lowest rate from the years 2000 to 2014. We applied this rate to GBD prevalence results for 195 countries to estimate transfusion needs. Unmet need was the difference between the estimated supply and need. FINDINGS: In 2017, the global blood need was 304 711 244 (95% uncertainty interval [UI] 293 064 637-314 049 479) and the global blood supply was 272 270 243 (268 002 639-276 698 494) blood product units, with a need-to-supply ratio of 1·12 (95% UI 1·07-1·16). Of the 195 countries, 119 (61%) did not have sufficient blood supply to meet their need. Across these 119 countries, the unmet need totalled 102 359 632 (95% UI 93 381 710-111 360 725) blood product units, equal to 1849 (1687-2011) units per 100 000 population globally. Every country in central, eastern, and western sub-Saharan Africa, Oceania, and south Asia had insufficient blood to meet their needs. INTERPRETATION: Our data suggest that the gap between need and supply is large in many low-income and middle-income countries, and reinforce that the WHO target of 10-20 donations per 1000 population is an underestimate for many countries. A continuous expansion and optimisation of national transfusion services and implementation of evidence-based strategies for blood availability is needed globally, as is more government support, financially, structurally, and through establishment of a regulatory oversight to ensure supply, quality, and safety in low-income and middle-income countries. FUNDING: National Institutes of Health.

Blood safety assessment of hepatitis A outbreak linked to frozen pomegranate arils: are foodborne outbreaks an emerging blood safety risk?

BACKGROUND: Foodborne hepatitis A virus (HAV) outbreaks are becoming more common in high-income countries with low HAV incidence, and the associated blood safety risk may not be adequately mitigated by routine HAV risk mitigation strategies. This study describes the rapid risk modeling undertaken in response to a 2018 HAV outbreak in Australia associated with imported frozen pomegranate arils. STUDY DESIGN AND METHODS: The input parameters used in the modeling were the outbreak-associated HAV incidence, duration of viremia, population seroprevalence, and rate of symptomatic infection in adults. The number and risk of viremic components issued, cases of transfusion transmission, and symptomatic infections among recipients were estimated. RESULTS: The incidence of pomegranate-associated HAV infection among donors was very low, with fewer than 0.1 viremic fresh components estimated to have been released during the risk period. The risk of this event was less than one in 500,000, and the risks of transfusion transmission and symptomatic illness in recipients were less than one in one million. When considering only donors who had consumed the pomegranate product, the risk was much higher, with approximately one in 1000 components estimated to be viremic. CONCLUSION: Rapid risk assessment indicated that the overall risk to blood safety associated with a small foodborne outbreak of HAV was negligible. Because fresh components collected from donors known to have consumed the affected product were at high risk, these donors were identified via signage in donor centers and deferred. The contribution of factors other than outbreak size to risk management decisions is discussed.

Tattoos, blood-borne viruses and blood donors: a blood donor cohort and risk assessment.

BACKGROUND AND OBJECTIVES: There is conflicting evidence in the literature as to whether there is a blood-borne virus (BBV) risk associated with tattoos in licensed premises. However, blood donors are currently deferred from blood donation in Australia for 4 months after any tattoo. We aimed to assess the incidence of BBVs in blood donors who declared tattoos and evaluate the risk to blood safety through risk modelling. MATERIALS AND METHODS: Donors from 2013 to 2016 with a tattoo deferral on their blood donor file with pre- and post-BBV testing were analysed to determine an incidence of BBVs using standard methods. This was compared to a 2014 cohort of whole blood donors with a deferral of 4 months due to travel to a malaria-endemic area. Using the incidence of tattoos and BBV risk, the total residual risk estimate of allowing tattooed donors to return without restriction was calculated. RESULTS: The incidence rate of BBVs in blood donors following tattoo deferral was 13·26 (95% CI 2·67-38·75) per 100 000 person-years (all were hepatitis C infections in males compared to 9·26 (95% CI 2·49-23·71) per 100 000 in blood donors following malaria deferral. If other risk factors were accounted for the risk in tattoo donors decreased to 4·4 per 100 000 person-years. The total residual risk calculation if donors with a tattoo were allowed to donate without restriction was estimated at 1 in 34 million. CONCLUSIONS: This residual risk indicates BBV deferral for donors post-tattoo in Australia is not required for blood safety.

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.

Serologic assessments in acute transfusion reactions: practices and yields.

BACKGROUND & OBJECTIVES: Serologic testing after transfusion reactions (TRs) aims to find accountable immune haemolytic incompatibility. Our hospital policies recommend serologic testing in all TR, except for low-risk fevers (subclinical temperature <39°C) or uncomplicated allergic reactions. Assessing compliance with these guidelines and serologic testing yields may provide insights on quality of practice and value. MATERIALS & METHODS: Interrogation of two haemovigilance databases identified all possible-to-definite TR over a 4-year period (2013-2016) at four academic hospitals. We reviewed the performance and outcome of serologic testing by site, year, reaction type, implicated product and service. RESULTS: Serologic testing occurred in 769 (55%) of 1408 referrals, with 1153 (82%) compliant with guidelines. Similar proportions deviated to overtesting (85/550 [15%]) and undertesting (174/858 [20%]), with undertesting seen most often in atypical TR. Overall, 30 (4.4%) of 769 cases had a new finding, but only 2 (0.3%) reflected host-derived antibodies. Overall, the number needed to test to discover an unexpected allospecificity was 385, or 253 if limited to high-risk fevers. Reaction- and product-specific yields ranged from 0% to 48%. The yield in complicated allergic reactions was low at 2%, constituting only predictable passive isohaemagglutinin(s) in retrospect. Investigated IVIG TR accounted for most of this cohort's signal by passive isohaemagglutinins in 48%. CONCLUSION: The performance of post-TR serologic testing revealed practice gaps and expected context-specific yields. Tailored serologic testing (i.e. indirect antiglobulin tests for alloantibodies in post-RBC/high-risk febrile reactions, ± isoagglutinin-focused tests after IVIG or ABO-minor-mismatched platelets) may improve value and liberate resources for other unmet needs in TR investigation.