(181) Safety Surveillance for COVID-19 Vaccines at The National Pharmacovigilance Centre Lareb

Publication Number: 512

Background: With the COVID-19 vaccination campaign, Pharmacovigilance (PV) centres had to deal with high volumes of ICSRs, to be processed and assessed in a short time span. This necessitated the development of a dedicated system to enable near real-time vaccine safety monitoring at the Dutch PV Centre Lareb.

Objectives: To describe infrastructure, processes and methods for vaccine safety monitoring during the COVID-19 pandemic and to provide a summary of the results of safety monitoring of the COVID-19 vaccines involved in the Netherlands.

Methods: A specific COVID-19 vaccine web-based reporting form enabled collecting information on the vaccine administered, Adverse Events Following Immunisation (AEFI) and other conditional information needed to collect high quality information on specific AEFI. These answers were mapped to corresponding ICH E2B(R3) fields in the ICSR management system. Where possible batch numbers were retrieved from the national vaccination registry.

A fully automated process for reports enabled handling of the majority of common and known reported AEFI. All other ICSRs were triaged daily and were assigned to a “non-priority” team that handled reports on most common AEFI; or to a ‘high-priority team’, for assessing more complex (serious) ICRs. Signal detection was performed based on case-by-case assessment, a dedicated electronic reaction monitoring report on all incoming ICSRs, Observed over Expected Analysis and batch analysis.

Results: In 2021, Lareb received 183,836 ICSRs, a reporting rate of 0.6% of the total amount of vaccines given in the Netherlands. Considering the brand of vaccine; 54.3% were about the Pfizer vaccine, 20.5% about the AstraZeneca vaccine, 17.1% Moderna vaccine, 7.9% Janssen vaccine and 0.2% other. ICSRs were reported after the first (62.5%); second (33.2%) and third (4.3%) vaccination.
33.2% of all ICSRs were processed fully automatic. 4.2% was flagged as a ‘high priority’ report and 62.6% as ‘non-priority’. Batch-numbers were known in 73.1%.
887,954 AEFI were reported; the majority concerned well-known, non-serious AEFI. The percentage of serious ICSR was 2.4%. 0.3% of the ISCRs had a fatal outcome. 3.3% of cases were reported by healthcare professionals and 96.7% by patients. Signals were issued on thrombosis and thrombocytopenia, myocarditis, among others.
With respect to the various batches used, no signals of possible batch-related problems have been detected for the various brands of COVID-19 vaccines.

Conclusions: A new approach which is highly technical supportive enabled to process high volumes of ICSRs. The majority of AEFI concerned well-known, non-serious AEFI. The experiences for assessing ICSRs and performing signal detection gained may serve as a blueprint for future mass vaccination programs.