COVID-19 Vaccination in Hemophilia: Indirect Evidence on NSAID-associated Bleeding Risk

Abstract

Patients with hemophilia are at risk of bleeding due to coagulation factor deficiencies. Intramuscular (IM) vaccination, including vaccines against COVID-19, raises concerns regarding injection-site bleeding. Moreover, the widespread use of NSAIDs for post-vaccination symptoms may further increase bleeding risk. This review aims to evaluate the incidence and mechanism of bleeding in patients confirmed with hemophilia following COVID-19 vaccination and assess the potential additive risk associated with the use of NSAIDs. Available evidence indicates that bleeding events following vaccination are infrequent and predominantly mild. However, NSAIDs impair antiplatelet aggregation and may exacerbate bleeding risk when combined with underlying coagulation defects. Direct evidence is strictly limited; nevertheless, pharmacological and indirect clinical data support a synergistic interaction. COVID-19 vaccination is systematically safe in hemophilia patients based on the available data from the selected studies; however, NSAID use represents a modifiable risk factor for bleeding, and safe alternatives such as paracetamol should be prioritized.