ABSTRACT
Background: Coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2), has resulted in an ongoing world-wide pandemic. Vaccination is the key countermeasure of the COVID-19 pandemic. Data on the efficacy, safety and immunogenicity of COVID-19 vaccination in patients with hemophilia -and in particular in those with HIV -are still scarce. Aim(s): The aim of our study was to characterize the immunogenicity and biomarkers of coagulation and endothelial perturbation after mRNA-COVID- 19 vaccination in HIV-positive hemophilic patients. Method(s): We collected blood from 24 adult HIV-positive hemophilic patients followed at our centre (19 with hemophilia A, 5 with hemophilia B) before and two weeks after the administration of the complete vaccination schedule with mRNA-1273 (Moderna Biotech). Most patients had severe hemophilia (n = 21). We measured antibodies to SARS-CoV- 2 spike protein by Elecsys (Roche) to assess immunogenicity and we evaluated protein C, VWF, D-dimer plasma levels as biomarkers of coagulation and endothelial perturbation. Anti-Platelet Factor 4 (PF4) antibodies were also measured. Result(s): Before vaccination, three patients out of 24 showed anti-Spike IgG levels >0.8 U/ml (cut-off value). Two weeks after completing the vaccination schedule, all patients had high values of anti-Spike IgG (min-max 2,387-12,500 U/ml). Mean (standard deviation) basal values of protein C, VWF and D-dimer (106 +/- 21%, 171 +/- 45%, 593 +/- 692 ng/ml respectively) were not significantly different from values measured two weeks after the second dose of vaccine (103 +/- 20%, 162 +/- 43%, 583 +/- 531 ng/ml). Anti-PF4 antibodies were detected in three patients with no associated clinical manifestations. None of the patients reported bleeding in the site of inoculation nor serious adverse events after the vaccination. Conclusion(s): Since immune abnormalities can occur in HIV-positive patients, it is important to collect data on COVID-19 vaccination immunogenicity. We demonstrated that hemophilic HIV-positive patients have a normal antibody response against SARS-CoV- 2 spike protein. In addition, mRNA-1273 had no effect on coagulation and endothelial perturbation.