The impact of COVID-19 vaccination on patients with a history of heparin-induced thrombocytopenia

The newly classified entity of vaccine induced thrombocytopenia and thrombosis (VITT) following AstraZeneca Vaccination is an area of ongoing investigation. The underlying pathophysiology is considered to have pathological similarities to heparin induced thrombocytopenia (HIT). It is unclear which cohorts may be particularly susceptible to developing VITT. In view of the underlying mechanism of action we undertook a retrospective analysis of patients with a history of HIT to assess whether they had been vaccinated and to assess whether any patients had experienced adverse reactions to the AstraZeneca vaccination. 20 out of 60 patients with a confirmed history of HIT received the AstraZeneca vaccination and none of these reported any features suggestive of VITT.