Suspected adverse reactions to COVID-19 vaccination and the safety of substances of human origin

Surveillance and monitoring

European Centre for Disease Prevention and Control. Suspected adverse reactions to COVID-19 vaccination
and the safety of substances of human origin – 3 June 2021. ECDC: Stockholm; 2021.

The purpose of this document is to address the safety of donors and products involving Substances of Human Origin (SoHO) and the potential risk of thrombosis with thrombocytopenia adverse events following COVID-19 vaccination of a donor. This document also supplements previous information provided on COVID-19 vaccination and supply of SoHO in the European Centre for Disease Prevention and Control (ECDC) technical report ‘Coronavirus disease 2019 (COVID-19) and supply of substances of human origin in the EU/EEA - second update’ [1]. ECDC will update the document and reassess the risk after consultation with relevant experts as soon as new information becomes available.

Executive summary

Key facts

  • Reports of thrombosis with thrombocytopenia syndrome (TTS) within two-to-three weeks of COVID-19 vaccination have raised questions regarding the safety of SoHO donors and recipients. The pathogenesis of TTS has not yet been determined, although laboratory analyses indicate the presence of anti-PF4-polyanion auto-antibodies.
  • Evidence and data currently available indicate a low likelihood of whole blood and plasma donation by asymptomatic individuals in the early phase of TTS, suggesting that the risk of venipuncture bleeding or post-transfusion thrombocytopenia with passive platelet antibody transfer is very low. Therefore, no additional blood and plasma safety measures are recommended in relation to the occurrence of suspected adverse reactions to COVID-19 vaccines.
  • A routine blood count check during the selection procedure for living donors of organs, cells and tissues donated by invasive procedure will detect thrombocytopenia. Individuals with a low platelet count would not be eligible for donation of organs, cells and tissues.
  • Until more information is available on the risk of TTS transfer via passenger lymphocytes, the decision to accept a deceased donor vaccinated with non-replicating viral vector COVID-19 vaccines two-to- three weeks before donation should be taken with caution.

Erratum: On 8 June 2021, Column 3 of Table 2 “Deferral period after suspected adverse reaction (p.5) was changed from “–" to “2 days”.