2. Summary

In 2021, Norway implemented a new digital portal for reporting several different types of adverse events, with the internet address www.melde.no. The implementation so far is successful and the Hemovigilance system now receives reports from all over the country. There is some misclassification, but the quality of the reports has improved during the year.

The Hemovigilance system has registered adverse reactions after blood transfusion in Norway since 2004.  One hundred fifty-five adverse reactions after blood transfusion were reported in 2021, 73 per 100 000 transfused units. Blood banks in South-Eastern Norway Regional Health Authority report less than what we could expect based on the population in that area, while blood banks in Western Norway Regional Health Authority report more. Fifty-five per cent of adverse reactions after blood transfusion take place in women.

In 2021 the distribution of adverse reactions after blood transfusion was;
 42 (27.1%) mild allergic reactions, 36 (23.2%) severe febrile non-hemolytic transfusion reactions (FNHTR), 25 (16.1%) transfusion associated circulatory overload reactions (TACO), 12 (7.7%) unclassifiable complication,  10 (6.5%) hypotensive transfusion reactions, 9 (5.8%) anaphylactic reactions, 7 (4.5%) «cannot conclude» reactions, 3 (1.9%) transfusion-associated dyspnea (TAD) reactions, 3 (1.9%) delayed hemolytic transfusion reactions and 4 (2.4%) other reactions. One acute hemolytic transfusion reaction (AHTR) due to ABO incompatibility, one transfusion associated autoimmune hemolytic reaction and one transfusion related acute lung injury (TRALI) were reported, but there were no reports of post-transfusion purpura (PTP), transfusion transmitted infections (TTI) or graft-versus-host disease (TA-GVHD).

Most adverse reactions after blood transfusion are reported from medical wards (52.3%), but some did also occur in surgical wards (12.3%) or the “Other” category (13.5%,) including emergency wards and oncological wards). 16.1% of the adverse reactions after blood transfusion had a moderate actual consequence, 12.3% had a severe actual consequence and one patient probably died due to TACO (imputability level two).

There were more reports of TACO in 2021 than in 2020. TACO is a grave transfusion reaction type and one of the reports had death as consequence while 11 of the TACO reports had a severe actual consequence. Some TACO reactions can be prevented when they are acknowledged and early diagnosis and is thus very important to give optimal treatment.

There were three reports of transfusion reactions after the use of convalescent plasma therapy against COVID-19, one TACO, one mild allergic reaction and one FNHTR. There were two reports of transfusion reactions after transfusion of whole blood: one acute hemolytic reaction and one febrile non-hemolytic transfusion reaction. The hemolytic reaction happened in a patient with a rare disease, probably contributing to the reaction.