ABSTRACT
Background: Concerns emerged for the management of intramuscular (IM) injections for COVID-19 vaccines in patients with therapeutic anticoagulation. Aim(s): The aim of the study was to evaluate the risk of bleeding events following IM vaccination in patients under therapeutic anticoagulation Methods: We first performed a French multicentre prospective study including patient treated by anticoagulant therapy for venous thromboembolism between May 2021 and September 2021. Consecutive patients were asked to report bleeding events at the site of COVID-19 vaccine injection during follow-up. We next performed a request in the French national pharmacovigilance database to identify cases of bleeding events at the site of injections following COVID-19 vaccine in patients under therapeutic anticoagulation between December, 27th, 2020 and June, 30th, 2021. Result(s): Between May and September 2021, a total of 348 patients with anticoagulant therapy received 561 IM injections of COVD-19 vaccines. Median age of patients was 68.4 years and 65.2% were males. Almost all patients were treated with direct oral anticoagulant (DOAC 96.6%), 11 (3.2%) patients with vitamin K antagonist and one (0.2%) with tinzaparin. Among them, 17.9% had pressure at the injection site after the injection and 4.2% had anticoagulant dose skipping before vaccination. After IM injections, a total of 3 (0.6%) bleeding events were observed, 2 (0.4%) minor and one (0.2%) clinically relevant non-major bleeding. We next observed in the French national pharmacovigilance database a total of 13 bleeding events (all minor bleeding) at the site of injection in patients on therapeutic anticoagulation between December, 27th, 2020 and June, 30th, 2021. In France, 69,089,410 doses of COVID-19 vaccine were administered during this period. These bleeding events correspond to a spontaneous notification rate of 0.19 cases (95% CI 0.09-0.29) reported per million of doses administered. Conclusion(s): IM vaccination appears safe in patients under therapeutic anticoagulation in particular with DOAC, and may not require skipping doses.