Clive R. Seed

Background and Objectives: Until 25 July 2022, people who spent more than 6 months in the United Kingdom during the variant Creutzfeldt–Jakob disease (vCJD) risk period 1980–1996 (UK donors) were deferred from blood donation in Australia. Regulatory approval to remove the deferral was underpinned by published mathematical modelling predicting negligible vCJD transmission risk increase with a gain of 58,000 donations.Materials and Methods: The donor questionnaire retained the UK deferral screening question until a version update effective 12 February 2023, which enabled identification of the newly eligible cohort of UK donors. Their donations were tracked for a 6‐month period (25 July 2022–24 January 2023) and compared with baseline Lifeblood donation metrics and predicted gains.Results: A total of 38,462 UK donors attended to donate 78,762 times in the 6 months. Of these, 32,358 donors (females = 19,456, males = 12,902) successfully donated 67,914 times representing 8.4% of total collections.Conclusion: Cessation of the UK deferral resulted in donation gains exceeding modelled predictions because of a higher than predicted number of donors who donated at a higher rate. Had these newly eligible donors not donated, overall donation numbers would have been 88% of target rather than the 96% achieved.

Background: In Australia, men who have sex with men (MSM) are deferred from blood donation for 3 months from last sexual contact. Internationally, deferral policies for MSM are evolving in the direction of expanded inclusivity in response to community expectations. To inform future policy options, we assessed perceptions of the risk of HIV transmission from blood transfusion among Australian MSM.Study Design and Methods: Flux is an online prospective cohort of Australian gay and bisexual men (cis or trans, regardless of their sexual history) and other men who have had sex with men (gbMSM). We included questions on blood donation rules, window period (WP) duration, infectivity of blood from people with HIV on treatment and attitudes to more detailed questioning of sexual practices in the regular survey of Flux participants and conducted a descriptive analysis of responses.Results: Of 716 Flux participants in 2019, 703 responded to the blood donation questions. The mean age was 43.7 years (SD 13.6 years). Overall, 74% were willing to confidentially respond to specific sexual behavior questions, such as the last time they had sex and the type of sex they had, in order to be considered eligible to donate blood. The majority (92%) of participants correctly assessed the duration of the WP as less than 1 month. When asked whether transfusion of blood from a donor with HIV and an undetectable viral load could transmit HIV, just under half (48%) correctly said yes.Conclusion: Our study suggests Australian gbMSM are generally comfortable with answering more detailed questions regarding sexual activity during the assessment to donate, indicating they would do so honestly. gbMSM are knowledgeable about the WP duration, important for their ability to correctly self‐assess their HIV risk. However, half of participants incorrectly assessed the transmissibility by blood transfusion from an HIV positive person with an undetectable viral load, suggesting the need for a targeted education campaign.

Background and Objectives: Parallel testing of blood donations for hepatitis C virus (HCV) antibody and HCV RNA by nucleic acid testing (NAT) has been standard practice in Australia since 2000. Meanwhile, NAT technologies have improved, and HCV has become a curable disease. This has resulted in a significant reduction in the risk and clinical consequences of HCV transmission through transfusion. This study aimed to estimate the residual risk (RR) under various testing options to determine the optimal testing strategy.Materials and Methods: A developed deterministic model calculated the RR of HCV transmission for four testing strategies. A low, mid and high estimate of the RR was calculated for each. The testing strategies modelled were as follows: universal dual testing, targeted dual testing for higher risk groups (first‐time donors or transfusible component donations) and universal NAT only.Results: The mid estimate of the RR was 1 in 151 million for universal dual testing, 1 in 111 million for targeted dual testing of first‐time donors, 1 in 151 million for targeted dual testing for transfusible component donations and 1 in 66 million for universal NAT only. For all testing strategies, all estimates were considerably less than 1 in 1 million.Conclusion: Antibody testing in addition to NAT does not materially change the risk profile. Even conservative estimates for the cessation of anti‐HCV predict an HCV transmission risk substantially below 1 in 1 million. Therefore, given that it is not contributing to blood safety in Australia but consuming resources, anti‐HCV testing can safely be discontinued.

Background and Objectives: The risk of transfusion‐transmitted hepatitis C virus (HCV) infections is extremely low in Australia. This study aims to conduct a cost‐effectiveness analysis of different testing strategies for HCV infection in blood donations.Materials and Methods: The four testing strategies evaluated in this study were universal testing with both HCV antibody (anti‐HCV) and nucleic acid testing (NAT); anti‐HCV and NAT for first‐time donations and NAT only for repeat donations; anti‐HCV and NAT for transfusible component donations and NAT only for plasma for further manufacture; and universal testing with NAT only. A decision‐analytical model was developed to assess the cost‐effectiveness of alternative HCV testing strategies. Sensitivity analysis and threshold analysis were conducted to account for data uncertainty.Results: The number of potential transfusion‐transmitted cases of acute hepatitis C and chronic hepatitis C was approximately zero in all four strategies. Universal testing with NAT only was the most cost‐effective strategy due to the lowest testing cost. The threshold analysis showed that for the current practice to be cost‐effective, the residual risks of other testing strategies would have to be at least 1 HCV infection in 2424 donations, which is over 60,000 times the baseline residual risk (1 in 151 million donations).Conclusion: The screening strategy for HCV in blood donations currently implemented in Australia is not cost‐effective compared with targeted testing or universal testing with NAT only. Partial or total removal of anti‐HCV testing would bring significant cost savings without compromising blood recipient safety.

Background West Nile virus (WNV) is a potentially transfusion-transmissible virus endemic in the US. The aim of this study was to estimate the monthly WNV transfusion transmission (TT) risk in Australia associated with donors returning from the US in 2018 and consider the implications for mitigation strategies. Study Design and Methods We used a probabilistic risk model to estimate the monthly WNV TT risks for each outbreak state/district in the US for the 2018 transmission season and the cumulative monthly risk for all US states/districts. Results The highest monthly cumulative transfusion risk in Australia occurred in August 2018 when 746 West Nile neuroinvasive disease cases were reported in the US and the estimated mean WNV TT risk in Australia was 1 in 1.0 x 10(8) donations (95% confidence interval [CI]: 1.6 x 10(8)-7.0 x 10(7)). The highest risk during August was associated with California, with a mean risk of 1 in 4.1 x 10(8) donations (95% CI: 2.9 x 10(8)-6.6 x 10(8)), representing 24% of the total risk in Australia. The cumulative TT risk in Australia for the other 11 months varied from 1 in 1.5 x 10(8) donations (95% CI: 2.3 x 10(8)-1.0 x 10(8)) in September to 1 in 3.9 x 10(10) donations (95% CI: 6.1 x 10(10)-2.7 x 10(10)) in February. Discussion Our modeling indicates that the WNV TT risk in Australia associated with seasonal outbreaks in the US is extremely small and may not warrant donation restrictions for donors returning from the US.

A widespread outbreak of Japanese encephalitis virus (JEV) was detected in mainland Australia in 2022 in a previous non-endemic area. Given JEV is known to be transfusion-transmissible, a rapid blood-safety risk assessment was performed using a simple deterministic model to estimate the risk to blood safety over a 3-month outbreak period during which 234,212 donors attended. The cumulative estimated incidence in donors was 82 infections with an estimated 4.26 viraemic components issued, 1.58 resulting in transfusion-transmission and an estimated risk of encephalitis of 1 in 4.3 million per component transfused over the risk period. Australia has initiated a robust public health response, including vector control, animal control and movement, and surveillance. Unlike West Nile virus, there is an effective vaccine that is being rolled-out to those at higher risk. Risk evaluation considered options such as restricting those potentially at risk to plasma for fractionation, which incorporates additional pathogen reduction, introducing a screening test, physicochemical pathogen reduction, quarantine, post donation illness policy changes and a new donor deferral. However, except for introducing a new deferral to potentially cover rare flavivirus risks, no option resulted in a clear risk reduction benefit but all posed threats to blood sufficiency or cost. Therefore, the blood safety risk was concluded to be tolerable without specific mitigations.

Background and Objectives Most of the 233 worldwide cases of variant Creutzfeldt-Jakob disease (vCJD) have been reported in the United Kingdom and 3 have been associated with transfusion-transmission. To mitigate the potential vCJD risk to blood safety, Australian Red Cross Lifeblood imposes restrictions on blood donation from people with prior residency in, or extended travel to, the United Kingdom during the risk period 1980-1996. We have modified a previously published methodology to estimate the transfusion-transmission risk of vCJD associated with fresh component transfusion in Australia if the UK residence deferral was removed. Materials and Methods The prevalence of current pre-symptomatic vCJD infection in the United Kingdom by age at infection and genotype was estimated based on risk of exposure to the bovine spongiform encephalopathy agent for the period 1980-1996. These results were used to estimate the age-specific prevalence of undiagnosed, pre-symptomatic vCJD in the Australian population in the current year due to prior UK residency or travel. The primary model outputs were the 2020 vCJD risks/unit of vCJD contamination, transfusion-transmission (infections) and clinical cases. Results The overall (prior UK residency in and travel to United Kingdom, 1980-1996) mean risk of contamination per unit was 1 in 29,900,000. The risks of resulting vCJD transmission (infection) and clinical case were 1 in 389,000,000 and 1 in 1,450,000,000, respectively. Conclusion Our modelling suggests that removing the Lifeblood donation deferral for travel to, or UK residence, would result in virtually no increased risk of vCJD transfusion-transmission and would be a safe and effective strategy for increasing the donor base.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel human coronavirus first identified in late 2019 and subsequently declared a worldwide pandemic in March 2020. In this review, we provide an overview of the implications of SARS-CoV-2 for blood safety and sufficiency. Summary: Approximately one-third of SARS-CoV-2 infections are asymptomatic. The reported mean incubation period typically varies from 2 to 11 days, but longer periods up to 22 days have been reported. The blood phase of SARS-CoV-2 appears to be brief and low level, with RNAaemia detectable in only a small proportion of patients, typically associated with more severe disease and not demonstrated to be infectious virus. A small number of presymptomatic and asymptomatic blood phase cases have been reported. Transfusion-transmission (TT) of SARS-CoV-2 has not been reported. Therefore, the TT risk associated with SARS-CoV-2 is currently theoretical. To mitigate any potential TT risk, but more importantly to prevent respiratory transmission in donor centers, blood services can implement donor deferral policies based on travel, disease status, or potential risk of exposure and encourage staff vaccination. Key Messages: The TT risk of SARS-CoV-2 appears to be low. The biggest risk to blood services in the current COVID-19 pandemic is to maintain the sufficiency of the blood supply while minimizing respiratory transmission of SARS-CoV-2 to donors and staff while donating blood.

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.