Experience in Pharmacovigilance Activities on COVID-19 Vaccine under the Pandemic

Abstract

The worldwide pandemic of COVID-19 brought a significant impact in Japan. Pfizer Japan Inc. received exceptional approval of COMIRNATY in February 2021. Temporary vaccination was initiated 3 days later. Pharmacovigilance at the start of sales is particularly important because the use experience is limited under the circumstances of exceptional approval. Therefore, we considered it essential to collect and analyze the safety information certainly and rapidly, and to provide the information in securing the safety of users and promoting the temporary vaccination project. Prior to the use of COMIRNATY, we estimated the number of adverse event (AE) reports based on anticipated amount of the product supply as well as the prediction from a scientific article on the AE reporting rate in the latest H1N1 influenza pandemic, and then we started to build a system including resources in the Safety Unit. However, partly owing to promotion of the vaccination, the actual number of AE reports received was the one we had never experienced. Pfizer prioritized processing of serious cases and secured resources in the Safety Unit based on vaccination status and number of AE reports. For Early post-marketing phase vigilance (EPPV), Pfizer Japan Inc. used information on vaccine delivery available on the Vaccination System (V-SYS) and conducted the provision and collection of information by leveraging digital technology. In this article, we report our experience of pharmacovigilance conducted as a marketing authorization holder of COMIRNATY under the COVID-19 pandemic, and touch upon matters that require improvement, should a pandemic occur in the future.