Relapses of Immune Thrombocytopenia after the second and booster doses of BNT162b2 Vaccine

We present here a 65-year-old male patient known for immune thrombocytopenic purpura (ITP) and fluctuating platelet count who experienced a severe exacerbation of thrombocytopenia following BNT162b2 COVID-19 vaccination. One month after the second dose he presented petechiae and asthenia with isolated thrombocytopenia (platelet count: 3 x 109/L). He recovered after a 4-day course of intravenous corticosteroid treatment and intravenous immunoglobulin therapy. Eight months later his platelet count was within the normal ranges and he received a booster dose of vaccine after pre-medication with prednisone. Eight days later his platelet count dropped to 29 x 109/L but he remained asymptomatic. He received a rescue treatment with prednisone followed by rituximab over 4 weeks allowing progressive improvement. Our case suggests a strong association between COVID-19 vaccination and the exacerbation of ITP.