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.
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.
BACKGROUND
Some countries impose an upper age limit on whole blood and double RBC donation while others do not. We evaluated the safety of blood donation in older individuals (≥71 years), and their contribution to the blood supply of five countries.
STUDY DESIGN AND METHODS
Twelve blood center members of the Biomedical Excellence for Safer Transfusion (BEST) Collaborative from four countries with no upper age limit for whole blood and double RBC donation (Canada, New Zealand, England, and the United States) or an upper age limit of 80 (Australia) provided 2016 data on donors and donations, deferral rates, and vasovagal reactions by donor age and sex. Donors under age 24 were included in the number of total donors and donations, but not in deferral and reaction rate comparisons.
RESULTS
Older donors accounted for 1.0% (New Zealand) to 4.3% (United States) of donors, and 1.5% (New Zealand) to 5.6% (United States) of donations; most were between ages 71 and 76. The deferral rate was higher in older compared to 24‐ to 70‐year‐old males, but very similar between older and younger females. In contrast, vasovagal reaction rates were either lower (male donors) or similar (female donor for reactions with loss of consciousness) in older compared to 24‐ to 70‐year‐old donors.
CONCLUSIONS
Exclusion solely based on older age appears to be unwarranted based on safety concerns such as donor reactions. Healthy older individuals can continue to safely donate and make a significant contribution to the blood supply past arbitrary age limits.
Informing donors of the possibility of re-entry appears to contribute to maintaining a positive predisposition towards future blood donation. It does not, however, appear to alleviate the distress felt after being notified of a false-positive infectious disease marker result, nor does it increase willingness to give blood again in the future.
Women who donate blood on a regular but moderate basis do not appear to be at higher risk of adverse pregnancy outcomes. These findings, while reassuring, will need to be replicated in different settings.
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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.
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