Active surveillance of immunization adverse effects: a multicentre, open-label, three-arm randomized uncontrolled trial in Ethiopia.

Background: Participant-centred active adverse event following immunization (AEFI) surveillance can offer real-time vaccine safety data and help in signal detection. This study aimed to evaluate the effectiveness of participant-centred active adverse events (AEs) surveillance following measles immunization in Gedeo Zone health facilities in Ethiopia.

Methods: An open-label, multicentred, three-arm randomized uncontrolled trial was conducted from 1 June to 21 October 2023.