Blood donations save lives. The Paul-Ehrlich-Institut highlights this fact on the occasion of World Blood Donor Day on 14 June 2025. As the Federal Institute for Vaccines and Biomedicines, the Paul-Ehrlich-Institut monitors the safety of blood and blood products, provides transparent information about any necessary measures, and is committed to maintaining reliable supply levels. A recent study by the Institute investigated blood donations classified as potentially containing West Nile virus from 2020 to 2023. The aim of the study was to review the Paul-Ehrlich-Institut's risk-minimising guidelines and their effectiveness with regard to the safety of blood products. The study found that a screening method ordered by the Paul-Ehrlich-Institut in 2019, which is based on a nucleic acid amplification test (NAT), currently appears to be a sufficiently effective method for risk minimisation.
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Since the first detection in 2019 of West Nile virus (WNV) transmissions, i.e. infections acquired locally in Germany, various risk minimisation measures have been introduced here on the recommendation of the Paul-Ehrlich-Institut. These measures include temporary donor deferrals and donor screening by means of a nucleic acid amplification test. However, like any test procedure, this test must be constantly evaluated and adapted to new virus variants and the number of infections.
The Paul-Ehrlich-Institut recently carried out a study in order to conduct such an evaluation. The study subject was an analysis of blood donations suspected of containing the WNV. The evaluation of the reported data and the examination of blood samples took place over a period of four years (2020 to 2023).
The Paul-Ehrlich-Institut has prescribed a WNV donor screening since 2019 that is based on nucleic acid amplification technology with a detection limit of at least 120 IU/ml. The examination of the blood samples submitted showed that this screening is well suited to reliably detect infected donors in an early infection phase or with a low viral load. Using such a test makes it possible to sufficiently reduce the risk of WNV transmission by blood components.
Two other test methods were found to only be suitable to a limited extent for routine donor screening.
A method was applied that can be used to determine the virus genome – Metagenomics Next-Generation Sequencing (mNGS) – and this method did recognise the WNV infections. However, cross-reactions with related viruses (other flaviviruses) could also be detected, which led to false positive results.
With the help of antibody testing, it was possible to detect donors in a late stage of infection or past the end of the infectious phase. Infections in the early phase were not detected.
The Paul-Ehrlich-Institut believes that there is still a need for continuous evaluation and adaptation of screening strategies to ensure the safety of blood donations in the long term, also with respect to new virus variants.
The Paul-Ehrlich-Institut is the German higher federal authority responsible for the safety, quality, and efficacy of blood and blood products. The Institute monitors the collection, production, and use of blood components and ensures that risks from blood-borne infectious agents are detected at an early stage and appropriate protective measures are taken. Its monitoring activities include the use of modern testing procedures, risk assessments, and the introduction of appropriate measures to minimise risk.
The Paul-Ehrlich-Institut also checks and assesses the authorisation of medicinal products produced from plasma, such as immunoglobulins, coagulation factors, or fibrin glues. The regular haemovigilance and transfusion reports published by the Institute create transparency and make an important contribution to the safety and availability of vital blood products in medical care. Since 2021, the Paul-Ehrlich-Institut has also worked with cooperating blood donation institutions to keep records on the supply of blood components throughout Germany and publishes the information weekly on its website in the "Blood Donation Barometer". The barometer allows for the detection of imminent, blood group-specific supply shortages in good time and the initiation of any necessary corrective measures.
Updated: 13.06.2025
