Donors and patients continued to enjoy a high level of safety. The epidemiological situation in Europe and Switzerland was monitored continuously to support the early identification of potential risks to the blood supply. The numbers of infectious diseases transmitted through blood transfusions remained at a similarly low level as in previous years.
One year after the introduction of uniform blood donation eligibility criteria that omit any reference to sexual orientation, there has been no increase in the risk of infection associated with donated blood or receipt of a transfusion by a patient.

Side effects from blood donation

• Cases reported: 3’183 (previous year: 3,183)

• Rate: 11,2–12,2 per 1,000 collections (previous year: 11.2–12.2 per 1,000 collections)

• Mild reactions: 92 % (previous year: 92 per cent)

→ Overall incidence of side effects remained stable, and the side effects were predominantly mild.

As of 1 February 2026, a revised version of the eligibility criteria for blood donation will apply throughout Switzerland. Persons previously ineligible to donate due to a blood transfusion, certain medical procedures or a longer period spent in the United Kingdom are now once again eligible to donate.

The purpose of the ineligibility criteria under the previous rules was preventative: to protect against the possibility of transmission of variant Creutzfeldt-Jakob disease (vCJD). An expert group assessed the present-day risk of transmission as extremely low based on recent scientific findings, international data and a comprehensive risk assessment.

The revision of the criteria was requested in October 2024 and approved by Swissmedic on 14 July 2025.

The evaluation of haemovigilance data for all of Switzerland indicated that blood donation and apheresis donation are safe, even for persons over the age of 65. Adverse events associated with whole blood donation were even rarer among this age group, a finding attributed to the selection of healthy, experienced donors. For apheresis donation, the frequency of events was somewhat higher and varied from one regional blood transfusion service to the next; this may be due in part to differences in documentation practices and preventive measures. Overall, the data confirm the international evidence attesting to the safety of donation for older adults.

Infectious diseases transmitted by mosquitoes, such as dengue, chikungunya and West Nile virus, are closely monitored across Europe as they can potentially be transmitted via blood products. Monitoring takes place seasonally between June and November and focuses on affected regions.

The monitoring results for Europe presented a mixed picture in 2025: while dengue infections were reported in individual regions of France and Italy, their occurrence remained limited and fell towards the end of summer. By contrast, localised outbreaks of chikungunya were reported in France and Italy for the first time; these are thought to have been triggered by cases imported from areas where the virus is endemic.

The number of cases of West Nile disease reported in 2025 came in below the average for the past ten years. Individual regions in Italy, France and Germany came under temporary bars during the 2025 season once again. Switzerland’s first reported case of autochthonous transmission was identified in Ticino after the mosquito season had ended. While this had no impact on the safety of blood donations, it does underscore the importance of pro-active preparations.

Overall, it was clear that the monitoring of tropical pathogens remains an important pillar for patient safety. The existing monitoring and precautionary measures have proven their worth and make it possible to identify risks early on and take targeted action against them.