ABSTRACT
Background/Introduction: Immunization errors (IEs) are one of the types of adverse events following immunization (AEFI) considered as preventable. They result from errors in vaccine preparation, handling, storage or administration [1]. Objective/Aim: To describe the profile of IEs related to COVID-19 vaccines reported to the Centre Anti Poison et de Pharmacovigilance du Maroc (CAPM) and risk minimization actions (RMAs) taken proactively and reactively to prevent IEs occurrence. Methods: We conducted a prospective analysis of IEs reported to the CAPM as part of the surveillance of AEFI related to COVID-19 vaccines. Data were collected using the AEFI reporting form, the electronic line listing and the hotlines established as part of the national COVID-19 immunization campaign launched on 28 January 2021. Immunization errors were classified according to their occurrence in the vaccine use process and their type using MedRRA. Investigations were performed to identify causes and contributing factors that lead to IEs, in the view of implementing RMAs. Results: As of 11 June 2021, the total number of IEs was 56, with an incidence of 4 cases per million doses of vaccine administered. All IEs were reported by healthcare professionals (HCPs). They occurred at the administration stage (n = 51) and the preparation stage (n = 5). The administration of the wrong vaccine was the main type of IEs (n = 26), followed by the inappropriate schedule of vaccine administration (n = 20). Two patients presented harm and two vaccinators developed ophthalmic adverse reaction. Prior to the launching of the campaign, proactive RMAs were designed: (i) training of HCPs involved in the campaign on the process of maintaining the cold chain, preparation and administration of vaccines and the workflow of an immunization session, (ii) the exclusively use of one type of vaccine in the same vaccination site, (iii) the development of an information technology system for managing patient appointments to be vaccinated. The investigations performed revealed that organizational issues were the main cause behind IEs happening, particularly at vaccination sites that were strained to use both available vaccines. Reactive measures, implemented in collaboration with the National Immunization Committee, highlighted the importance of seeking for contraindications or reasons that would affect patient suitability for vaccination, and applying best practices for immunization session management. Conclusion: The proper planning of proactive RMAs is key to reduce the likelihood of IEs. Moreover, immunization process vulnerabilities identified following IEs happening, should be tackled to prevent harm and maintain population confidence in the national COVID-19 campaign.