Debunking three common misconceptions about blood transfusion-transmitted infection

In the population, the perceived risk of acquiring a transfusion-transmitted infection is greater than it needs to be.

When asking patients and caregivers or the general public about how they perceive the risks of blood transfusions, in many countries one answer is predominant: “I am afraid of getting an infection.”

So, if you have ever found yourself thinking about needing a blood transfusion at some point in your life or gone even further to worrying about receiving a microbially contaminated blood unit, you are not alone.

As an aspiring researcher in the field of blood donation safety, I recognize three widely distributed concerns regarding blood transfusions. Here is why they are less substantial than they might seem at first.

Myth 1: Transfusion-transmitted infection is common

The fear of receiving a contaminated donation is big but, in reality, the risk of it is vanishingly small: for example, of all transfusion complications in the EU in 2018, only 0.4 percent stemmed from the transfusion of a bacterially contaminated product and 0.8 percent were attributed to a virus-containing unit. In the US, the chance of receiving a transfusion contaminated with hepatitis B or C or HI virus is between 1:500 000 and one to a million. This means 24, 15 and 12 cases per year, respectively.

Of course, this is still too much, but to put things into perspective: in 2018 in the EU, 1 687 serious adverse events during or after a transfusion were reported, with reactions due to unknown causes, febrile non-hemolytic transfusion reactions (an uncomfortable to lethal reaction with flu like symptoms and generalized pain) and allergic or anaphylactic reactions being in the lead. Of all events, 20 ended with the recipient’s death, and only 10 percent of the deaths occurred due to a microbially contaminated platelet product.

Furthermore, methods for inactivating potentially contained pathogens in blood products, and therefore rendering them harmless, are continuously advancing. They will very likely extinguish the risk of transfusing a microbially contaminated unit in the near future, as well as simultaneously decrease the need for testing the donations in general.

Myth 2: Infection always happens as soon as a contaminated unit is transfused

Although an infection transmission is quite likely if a pathogen-containing blood unit is transfused, it is not inevitable. There are many pathogen-, donor-, transfusion- and recipient-related factors which influence the establishment of an infection in the recipient.

Such factors are, for example, the pathogen load and its genotype, meaning mutations that result in high or low pathogenicity. Donor factors could be the state of the infection or the development of antibodies, whereas recipient-related factors include the immune status or the received blood volume. It also matters which blood components get transfused. This holds true also for very concerning pathogens like HIV.

Myth 3: Former residents of the UK, Ireland and France are banned from donating

For a long time, people who spent time in the UK between 1980 and 1996 or France or Ireland between 1980 and 2001 were deferred from donating blood. The same applied to people who had received a blood transfusion in said countries between 1980 and 2022.

This was due to the outbreak of the deadly variant Creutzfeldt-Jakob disease, also known as the mad cow’s disease, in these regions during those years. The transfusion transmission had been deemed to be very likely.

In May 2022, the U.S. Food and Drug Administration (FDA) reassessed the situation and, based on the fact that transfusion-transmitted infection has never been proven and nowadays seems very unlikely, decided that the deferral could be lifted.

This means that previously deferred donors are eligible to donate blood again. However, the recommendations are not binding, and decisions are up to national consideration. So far, the Finnish Red Cross has not lifted the permanent deferral strategies.

The risks are close to non-existent

Blood transfusions are an important part of our modern medicinal care and according to estimations almost everybody needs one at some point in their lives. However, many people are afraid of getting infected by being transfused a microbially contaminated blood unit, but the actual risk is close to non-existent. If you are a willing donor on the other hand but have been affected by the deferral related to your stay in the UK, Ireland or France and the associated mad cow’s disease, you might want to keep an eye on updates, e.g., by the Red Cross in your country, as the deferral guidelines have been lifted by the FDA and could be changed on national level any time.


Theresa Kaudela, MSc in Engineering, has a background in biomedical science and molecular analytics from studying in Austria. She has recently started her doctoral studies with the topic “Evaluating the Prevalence and Characteristics of Chlamydia pneumoniae, Its Structural Components and Infection-Induced Leukocyte-Derived Extracellular Vesicles in the Blood of Finnish Blood Donors” at the University of Helsinki. Research portal: Theresa Kaudela – University of Helsinki


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