Acquired hemophilia A (AHA) due to anti‐SARS‐CoV‐2 vaccination: A systematic review

Vaccination against SARS‐CoV2 has been the largest vaccination campaign over the past two decades. The aim of this study is to qualitatively assess the reported cases of acquired hemophilia A (AHA) that developed after COVID‐19 vaccination to further elaborate on incidence, presentation, treatment, and outcomes.We queried Medline (PubMed), Google Scholar, and Embase databases to find reported cases of AHA after COVID‐19 vaccines. We found 14 studies (19 cases) for this descriptive analysis. Most patients were elderly (mean age 73 years) and males (n = 12) with multiple comorbidities. All cases developed after mRNA vaccines ‐ BNT162b2 Pfizer‐BioNTech (n = 13) and mRNA‐1273 Moderna (n = 6). All except one patient were treated, with the most common therapy being a combination of steroids, immunosuppression, and rFVIII (n = 13). Two patients died due to acute respiratory distress, and gall bladder rupture with persistent bleeding, respectively. While evaluating a patient with bleeding diathesis after COVID‐19 vaccination, AHA should be kept in the differential diagnosis. Given the low incidence, we believe that the benefit of vaccination still outweighs the risk of disease acquisition.