How safe is safe enough, who decides and how? From a zero-risk paradigm to risk-based decision making

Why Does the Precautionary Principle Suffice for Blood Regulation?

Traditional approaches to blood regulation emphasise the precautionary principle and pursue zero-risk for viral transmission; these traditional approaches have usually followed tragedy, such as the HIV and hepatitis C infections that followed the use of factor VIII concentrates. However, a much more haphazard haemovigilance system operates for general adverse events. Such imprecise assessment of hazards prevents sound benefit-risk assessment, and for blood products this is further confounded by the fact that their efficacy has attracted little systematic study. The ongoing COVID-19 pandemic has now prompted the proposal of a convalescent plasma (CP) blood product. Clearly, mere freedom from infectious agents will not suffice in assessing CP, and an objective measure of efficacy, so as to permit formal benefit-risk analysis, is essential. This is both a scientific and an ethical demand, as has been the case for other experimental COVID-19 treatments. With special reference to COVID-19 CP, the well-recognized adverse events of transfusion-associated lung injury (TRALI) and transfusion-associated circulatory overload (TACO) will be important. Furthermore, not only efficacy but also product quality attributes (e.g., antibody titre) will have to be defined. Both of these are outside the traditional regulatory philosophy for blood products and are needed to truly assess the benefit-risk of this putative therapeutic product.

Science in action? A critical view of UK blood donation deferral policy and men who have sex with men

The rules that govern blood donation vary globally. Some potential blood donors are ineligible for immediate blood donation, and as such are deferred until such time that they become eligible. This practice, the blood donation deferral period, is intended to reduce the risk of blood-borne infections being transfused into a blood product-recipient. As blood screening technologies improve, the risk of an infected blood product remaining undetected decreases-and so too have the deferral periods for certain donors. Much has been made of the importance of an evidence-based, scientific approach to protecting blood product-recipients. However, these deferrals are controversial. What exactly determines the blood donation deferral period? This article argues that blood donation deferral periods are not merely the result of enacting empirical data. Instead, the deferral periods represent a negotiation between scientific evidence, experts, politically expedient narratives, institutionalised risk aversion, as well as more mundane concerns such as operational feasibility. As a case study, I examine how the UK Advisory Committee on the Safety of Blood, Tissues and Organs changed the 12-month deferral period for blood donation from men who have sex with men to a 3-month deferral period.

Transfusion medicine: Overtime paradigm changes and emerging paradoxes

This essay aims to discuss some aspects of blood transfusion in the perspective of the changes that occurred over time as well as modifications of the paradigms that transformed the activities and the organization of blood transfusion services. Without specific knowledge, pioneers envisioned precision and personalized medicine, rendering transfusion medicine operational. Transfusion medicine is like The Picture of Dorian Grey: always young despite being old and sometimes appearing old-fashioned. Over the years, the transfusion medicine discipline has evolved, and major progress has been achieved, despite some troublesome periods (for example, the tainted blood scandal, and—at the time being—the offending plasma market and the selling of human parts). Transfusion medicine has at all times implemented the rapidly developing biomedical technologies to secure blood components. The safety of blood components has now reached an exceptional level in economically wealthy countries, especially compared to other health care disciplines. Strengthening of the safety has mandated that blood donors and recipients are unrelated, an issue which has eased preservation and fractionation practices; blood is no longer arm-to-arm transfused and neither is whole blood, the commonest component. However, it is interesting to note that a revival is occurring as whole blood is back on stage for certain specific indications, which is one among the many paradoxes encountered while studying this discipline.

Malaria blood safety policy in five non-endemic countries: a retrospective comparison through the lens of the ABO risk-based decision-making framework

BACKGROUND

In non-endemic countries, malaria risk is addressed by selectively testing or deferring at-risk donors. These policy decisions were made using a variety of decision-making frameworks prior to the development of the Alliance of Blood Operators Risk Based Decision-Making Framework. It is unclear whether the range of items assessed in the decision-making process would be increased if the Framework were used. We compared assessments considered in France, England and Australia for decisions to implement selective testing, plus donor selection criteria (Canada and the USA included) with those recommended by the Framework.

MATERIALS AND METHODS

Elements of the Framework were identified: the intervention, safety threat, availability threat, donor impact, financial implications, risk communication, stakeholder and regulatory aspects. Decisions about selective testing and donor selection criteria were analysed separately. Assessments were compared against elements of the Framework and the level of concern for considerations rated.

RESULTS

Sufficiency of the blood supply (plus safety in France) were the drivers for selective testing; main trade-offs were high operational impact and cost. In three donor criteria examples, transfusion-transmitted malaria cases prompted the change. Social concerns were high in France and Australia, political/regulatory concerns influenced decisions in France, Australia and Canada, while sufficiency was a consideration in Canada and the USA. Decision trade-offs involved moderate operational impact.

DISCUSSION

The assessments considered in each country were generally consistent with the assessments recommended by the Framework. When data supported quantified risk assessment, safety and operational feasibility had the greatest weight. When risk was not well defined, contextual factors such as social and political concern had greater weight.

Donor blood screening and moral responsibility: how safe should blood be?

Some screening tests for donor blood that are used by blood services to prevent transfusion-transmission of infectious diseases offer relatively few health benefits for the resources spent on them. Can good ethical arguments be provided for employing these tests nonetheless? This paper discusses-and ultimately rejects-three such arguments. According to the 'rule of rescue' argument, general standards for cost-effectiveness in healthcare may be ignored when rescuing identifiable individuals. The argument fails in this context, however, because we cannot identify beforehand who will benefit from additional blood screening tests. On the 'imposed risk' argument, general cost-effectiveness standards do not apply when healthcare interventions impose risks on patients. This argument ignores the fact that imposing risks on patients is inevitable in healthcare and that these risks can be countered only within reasonable limits. Finally, the 'manufacturing standard' argument premises that general cost-effectiveness standards do not apply to procedures preventing the contamination of manufactured medical products. We contend that while this argument seems reasonable insofar as commercially manufactured medical products are concerned, publicly funded blood screening tests should respect the standards for general healthcare. We conclude that these particular arguments are unpersuasive, and we offer directions to advance the debate.

Direct costs of transfusion reactions - an expert judgement approach

BACKGROUND AND OBJECTIVES

Despite increasingly meticulous haemovigilance reporting throughout the world, a systematic assessment of the cost of transfusion reactions is still lacking. This is partly caused by the fact that such an assessment requires a subjective expert assessment of the additional costs linked to the adverse reaction. Data on the cost of transfusion reactions could support decision-making regarding blood transfusion safety measures.

MATERIALS AND METHODS

Thirteen experts from nine hospitals were asked to estimate the additional care required following various types of transfusion reactions. Additional care was quantified as the proportion of reactions requiring care, and the amount of care required (e.g. hospitalization days, additional physician's time). Experts were also asked to provide, per type of transfusion reaction, an estimate of the proportion of transfusion reactions preventable. Structured quantitative expert elicitation methods were applied to obtain and combine expert estimates.

RESULTS

The estimated annual in-hospital cost of transfusion reactions in the Netherlands is €933 356 per year (€1.52 per transfusion). Two-thirds (64%) of these are incurred by non-serious transfusion reactions. Circulatory overload, TRALI and anaphylaxis clearly dominate the costs of serious adverse transfusion reactions (66% in total); non-haemolytic transfusion reactions incur 46% of the cost of non-serious transfusion reactions. Additional safety measures targeting circulatory overload and new antibody formation potentially offer the highest cost reduction.

CONCLUSION

In-hospital costs of transfusion reactions are substantial but contribute to less than 1% of the total cost of transfusion in the Netherlands. A considerable part of these costs (24%) might be preventable.

Problems with precaution: the transfusion medicine experience

The precautionary principle is a dominant paradigm governing risk-based decision-making. Today, there are increasing pressures to re-examine aggressive precautionary approaches, and to assess how the principle should be applied in the modern system. In this paper, we examined three key applications of precautionary approaches in the field of transfusion medicine to provide insight into the risks and benefits of these approaches. The three case studies examined were the donor deferral policies to safeguard against transfusion transmission of human immunodeficiency virus, variant Creutzfeldt-Jacob disease, and, lastly, xenotropic murine leukemia virus-related virus. Characterization of precautionary applications was conducted using an embedded case study design. Our findings indicate that transfusion transmission mitigation strategies have become increasingly aggressive in the face of theoretical risks. In contrast, the review processes for implementation and reversal of precautionary policies have been slow, and historical donor deferral policies are still in place today. Application of precautionary approaches has proved challenging with both benefits and pitfalls. In light of emerging threats to the blood system, policy-makers should consider the implementation of frameworks to guide the appropriate application of precaution in transfusion medicine in the future.

Residual risk of HIV, HCV and HBV in Canada

BACKGROUND

Residual risk is estimated as the product of the incidence and the infectious window period, the time during which a blood donation could be infectious but the assay may not detect it. In 2011 nucleic acid multiplex testing (MPX) was implemented in 6 unit minipools (previously 24 unit minipools). MPX also included hepatitis B (HBV) NAT for the first time (complementing HBsAg screening) in addition to HIV-1 and hepatitis C (HCV) as before. We aimed to estimate window period risk-day equivalents for MPX, and the residual risk of viral infections in blood donations updated to reflect current incidence and testing.

METHODS

Transmissible disease conversions of repeat donations to Canadian Blood Services within the three-year period 2012-2014 divided by person-years estimated incidence for HIV, HCV and HBV (adjusted for transient viremia). Window period risk-day equivalents for MPX were estimated using a published method. Residual risk was the product of incidence and window period risk-day equivalents. 95% confidence intervals were estimated using Monte Carlo simulation of the window period risk-day equivalents and the incidence density 95% confidence intervals.

RESULTS

The incidence rate per 100,000 person years for HIV was 0.28, HCV 1.0 and HBV 0.26. The residual risk of HIV was 1 per 21.4 million donations, HCV 1 per 12.6 million donations and HBV 1 per 7.5 million donations.

CONCLUSION

The residual risk of infection is very low, similar to 2006-2009. The safety benefit of further shortening of the infectious window period is below the threshold to quantify.

The Precautionary Principle and the Tolerability of Blood Transfusion Risks

Tolerance for blood transfusion risks is very low, as evidenced by the implementation of expensive blood tests and the rejection of gay men as blood donors. Is this low risk tolerance supported by the precautionary principle, as defenders of such policies claim? We discuss three constraints on applying (any version of) the precautionary principle and show that respecting these implies tolerating certain risks. Consistency means that the precautionary principle cannot prescribe precautions that it must simultaneously forbid taking, considering the harms they might cause. Avoiding counterproductivity requires rejecting precautions that cause more harm than they prevent. Proportionality forbids taking precautions that are more harmful than adequate alternatives. When applying these constraints, we argue, attention should not be restricted to harms that are human caused or that affect human health or the environment. Tolerating transfusion risks can be justified if available precautions have serious side effects, such as high social or economic costs.

Zika and the Blood Supply: A Work in Progress

Zika virus can be transmitted by transfusion, but the harm caused to recipients is not clear in most cases. It is very likely that the virus could also be transmitted by transplanted organs. Sensitivity to the risk from transfusion is elevated by consideration of possible severe neurologic damage in fetuses. Strategies for dealing with transfusion risk vary with the presence of Zika in the region. In nonendemic areas, risks can be reduced by excluding donors who have exposure through travel or sexual contact with someone at risk. In both endemic and nonendemic areas, the risk can be further reduced by nucleic acid testing of donors, or pathogen reduction of platelet and plasma products. The real risk to the population depends on the frequency of infection as well as the efficacy of these interventions. The interventions chosen will depend on the risk assessment for any situation; in the United States at this time, a combination of travel deferrals, testing, and, to a lesser extent, pathogen reduction is being used, but universal testing of US blood donors under investigational use has been mandated by the US Food and Drug Administration, beginning with states most at risk of local transmission. Canada is largely using travel deferrals. A precautionary approach may be taken; however, a formal decision-making framework has been suggested. The situation globally is clearly very fluid, as the epidemic continues to spread and we continue to learn how to best protect recipients of blood and transplants.

Refining the risk estimate for transfusion-transmission of occult hepatitis B virus

BACKGROUND AND OBJECTIVES

We previously published a model to estimate the residual risk (RR) for occult hepatitis B infection (OBI) in the absence of universal anti-HBc testing. To incorporate new information on the epidemiology of OBI, we describe model refinements and estimate a more accurate HBV RR due to OBI in Australia.

MATERIALS AND METHODS

In our original model, the OBI risk, p(OBI), was defined by the rate of 'non-detection' by the HBV DNA screening test in use, p(NAT non-detection), and the average infectivity of blood components from OBI donors, p(transmission). We revised the model by integrating three refinements: that donations with anti-HBs levels of >10 IU/l, or donations solely for manufactured plasma products, be excluded from the risk calculation, and an updated estimate of p(transmission).

RESULTS

Refining our OBI RR model resulted in a more than 10-fold reduction in the reported RR risk to recipients from OBI in our donor population. Based on the use of a common data set, the mean OBI RR risk decreased from 1 in 374 354 donations (95% CI: 1 in 191 940-1 072 681) to 1 in 3 984 033 (95% CI: 1 in 1 146 188-65 268 257) for the refined model.

CONCLUSION

Our model refinements provide a more realistic measure of the HBV RR in the donor population. Unlike the previous model, the new model demonstrates that the risk of HBV due to OBI in the Australian blood donor population is negligible, and further potentially cost-ineffective risk management strategies are not currently warranted.

Blood-Borne Pathogens: A Canadian Blood Services Centre for Innovation Symposium

Testing donations for pathogens and deferring selected blood donors have reduced the risk of transmission of known pathogens by transfusion to extremely low levels in most developed countries. Protecting the blood supply from emerging infectious threats remains a serious concern in the transfusion medicine community. Transfusion services can employ indirect measures such as surveillance, hemovigilance, and donor questioning (defense), protein-, or nucleic acid based direct testing (detection), or pathogen inactivation of blood products (destruction) as strategies to mitigate the risk of transmission-transmitted infection. In the North American context, emerging threats currently include dengue, chikungunya, and hepatitis E viruses, and Babesia protozoan parasites. The 2003 SARS and 2014 Ebola outbreaks illustrate the potential of epidemics unlikely to be transmitted by blood transfusion but disruptive to blood systems. Donor-free blood products such as ex vivo generated red blood cells offer a theoretical way to avoid transmission-transmitted infection risk, although biological, engineering, and manufacturing challenges must be overcome before this approach becomes practical. Similarly, next generation sequencing of all nucleic acid in a blood sample is currently possible but impractical for generalized screening. Pathogen inactivation systems are in use in different jurisdictions around the world, and are starting to gain regulatory approval in North America. Cost concerns make it likely that pathogen inactivation will be contemplated by blood operators through the lens of health economics and risk-based decision making, rather than in zero-risk paradigms previously embraced for transfusable products. Defense of the blood supply from infectious disease risk will continue to require innovative combinations of surveillance, detection, and pathogen avoidance or inactivation.

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A symposium on blood-borne pathogens was held September 26, 2015, in Toronto, Canada.

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Transmission-transmitted infections remain a threat to the blood supply.

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The residual risk from established pathogens is small; emerging agents are a concern.

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Next generation sequencing and donor-free blood are not yet practical approaches.

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Pathogen inactivation technology is being increasingly used around the world.

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Health economic concerns will likely guide future advances in this area.

Blood donor selection in European Union directives: room for improvement

BACKGROUND

Transfusion-transmissible infections have made both blood bankers and health authorities overly cautious. The general public expects and hence reinforces this policy. To obtain a high level of blood product safety, blood and plasma donors have to meet increasingly stringent eligibility criteria; however, it is not known whether this policy translates into improved outcomes for patients. There is a risk that the management of donors does not match the ambition of greater safety for patients. European directives related to the collection process and donor selection will probably be reconsidered in the next few years.

MATERIAL AND METHODS

The development of European directives on donor selection and their basis in the literature were reviewed with an emphasis on the background and considerations for eligibility criteria to be included in the directives.

RESULTS

The precautionary principle appears to be the predominant reason behind the set of eligibility criteria. However, the formal eligibility criteria, put into force in 2004, do not balance with the developments of the past decade in laboratory tests and measures that have substantially reduced actual infection risks. In no cases were the effects of eligibility criteria on the donor pool and donor well-being quantified. Regional differences in the epidemiology of transfusion-transmissible infections were not taken into consideration either.

DISCUSSION

First, the Authors promote the collection of epidemiological data on the incidence and prevalence of conditions in the general population and in blood and plasma donors which could pose a risk for transfused patients, in order to use these data as a basis for decision-making in donor-selection policies. Second, the Authors suggest including allowance for differential deferral criteria throughout Europe, based on factual risk levels. There should be an accepted balance between donor and patient welfare, and also between risk to transfusion safety and risk of compromising the blood supply.

Emerging microbial threats to the United States blood supply

PURPOSE OF REVIEW

In this short review, several emerging agents are described to demonstrate potential responses of the blood community to emerging and potentially emerging infections.

RECENT FINDINGS

Critical questions are raised as we consider appropriate approaches to these agents. Can we identify risk thresholds below which interventions are not required, that is, are there tolerable infectious risks of transfusion? Who are the stakeholders responsible for that determination? What is the role of health economic analysis for informing those decisions? If we decide that cost-utility thresholds for transfusion medicine are appropriately several fold higher than for the rest of clinical medicine, who has responsibility for being certain whether those priorities are funded?

SUMMARY

Four agents will be discussed to highlight the evolving considerations in response to these considerations.

Is having sex with other men a risk factor for transfusion-transmissible infections in male blood donors in Western countries? A systematic review

BACKGROUND

Although increased prevalence of transfusion transmissible infections (TTI) among "men who have sex with men" (MSM) has been well documented, the exclusion of MSM as blood donors is contested. The aim of this systematic review is to find studies that describe the risk of TTI in MSM blood donors.

METHODS

We searched MEDLINE, Embase, The Cochrane Central Register of Controlled Trials, Cinahl, and Web of Science, and used GRADE for determining evidence quality. We included studies comparing MSM and non-MSM blood donors (or people eligible to give blood), living in areas most relevant for our Blood Service.

RESULTS

Out of 18 987 articles, 14 observational studies were included. Two studies directly compared MSM with non-MSM donors showing that MSM donors have a statistically significant higher risk of HIV-1 infections. In one of these studies it was shown that this was related to recent (< 12 months) MSM contact. In two additional studies no evidence was shown in favour of a certain deferral period for MSM. Ten studies, applying permanent deferral for MSM, compared infected versus non-infected donors. One study found that MSM is a statistically significant risk factor for HIV-1 infection in blood donors. For other TTI such as HBV or HCV, an increased risk of infection could not be demonstrated, because the precision of the results was affected by the low numbers of donors with MSM as risk factor, or because of risk of bias in the included studies. All studies included low level evidence, because of risk of bias and imprecision of the results.

CONCLUSIONS

High-quality studies investigating the risk of TTI in MSM who donate blood are scarce. The available evidence suggests a link between MSM blood donors and HIV-1 infection, but is too limited to be able to unambiguously/clearly recommend a certain deferral policy.

A clinical governance framework for blood services

BACKGROUND AND OBJECTIVES

The elements of clinical governance, which ensure excellence in clinical care, can be applied to blood services. In this survey, their application in a range of blood providers was gauged, with the aim of identifying best practice and producing a generalizable framework.

MATERIALS AND METHODS

The Medical Directors of members of the Alliance of Blood Operators surveyed how different elements of clinical governance operated within their organizations and developed recommendations applicable in the blood service environment.

RESULTS

The recommendations that emerged highlighted the importance of an organization's culture, with the delivery of optimal clinical governance being a corporate responsibility. Senior management must agree and promote a set of values to ensure that the system operates with the patient and donor at its heart. All staff should understand how their role fits into the 'journey to the patient', and a culture of openness promoted. Thus, reporting of errors and risks should be actively sought and praised, with penalties applied for concealment. Systems should exist to collect, analyse and escalate clinical outcomes, safety data, clinical risk assessments, incident reports and complaints to inform organizational learning.

CONCLUSION

Clinical governance principles from general health care can be applied within blood services to complement good manufacturing practice. This requires leadership, accountability, an open culture and a drive for continuous improvement and excellence in clinical care.

Blood Transfusion in the 21st Century

Blood transfusion is a common procedure in the hospital setting, and the safety of the blood supply has been vastly improved over the past few decades largely due to improvements in screening for viral transmissible diseases, especially human immunodeficiency virus (HIV) and viral hepatitis. However, more recent efforts to improve blood safety have focused on non-transmissible disease risks such as transfusion-related acute lung injury (TRALI), non-viral transmissible diseases such as bacterial contamination of blood products (especially platelet components which are stored at room temperature) and Chagas disease (a parasitic disease caused by Trypanosoma cruzi), and prion transmissible agents (e.g., variant Creutzfeldt-Jakob disease, also known as the agent of mad cow disease) as well as more recently-recognized transmissible viral disease risks such as West Nile virus. Appropriate blood utilization has also come under more intense scrutiny in recent times due to healthcare costs and the recognition that many blood transfusions are given under circumstances in which the benefit to the patients is unclear and may be potentially harmful due to the above risks as well as the emerging concept that blood transfusions may cause long-term damage to the immune system resulting in worse patient morbidity and mortality outcomes. Toward that end, accreditation agencies such as the Joint Commission and the American Association of Blood Banks (AABB) are advocating for healthcare organizations to implement appropriate patient blood management strategies. This review will examine these issues along with newer blood safety technological innovations and further highlight contributing studies from our institutions.