(A-359) Vaccine-related studies listed in the Heads of Medicines Agencies-European Medicines Agency (HMA-EMA) Catalogue of Real-World Data studies: What can we learn from study characteristics?

Background: The number of commercially launched vaccines has increased in recent years, as have the number of real-world data (RWD) studies - particularly since the onset of the COVID-19 pandemic - to assess safety and effectiveness of these vaccines.

Objectives: To provide an overview of key design characteristics of vaccine-related studies recorded in the HMA-EMA Catalogue of RWD studies.

Methods: We conducted a search of all vaccine-related studies contained within the HMA–EMA Catalogue of RWD studies published until 8 Jan 2025 and exported all study entries to identify their main design characteristics.

Results: The search identified a total of 164 studies registered in the HMA-EMA Catalogue of RWD studies. The number of studies notably increased in recent years: 51 (31.1%) had a start date prior to 2020 (range 2001-2019 [“pre-pandemic”]), whereas 49 (29.9%) and 64 (39.0%) had start dates of 2020 or 2021 (“pandemic era”) and 2022 or later (“post-pandemic”), respectively.
Median duration of the pre-pandemic studies was 19 months; the corresponding value for pandemic era and post-pandemic studies was 22 months. The median target sample size was notably larger in the pandemic era (N=57,000) and the post-pandemic period (N=42,755) versus studies started in the pre-pandemic period (N=11,530). Most (57.3% [94/164]) of the identified registered studies were required by a regulatory body.
Most studies began in the pandemic and post-pandemic eras were focused on vaccines that protect against COVID-19 (67, 59.3%). Among the 51 pre-pandemic studies, nearly one-half (47.1% [n=24]) were focused on vaccines that prevent influenza. Conversely, few (10.6% [n=12/113]) studies started in the pandemic or post-pandemic eras were focused on influenza vaccines. Other vaccines frequently studied were designed to protect against human papillomavirus (HPV) (8 studies), meningitis (8), and respiratory syncytial virus (RSV) (7).
The primary uses of these studies were to assess vaccine effectiveness (70.1% [N=115]) and safety (35.4% [N=58 studies]). The most used designs were cohort (69.5% [N=114]) followed by case-control (11.0% [N=18]). A nominal trend was observed concerning use of secondary data (44.7% of pre-pandemic studies were based exclusively on secondary data vs. 69.6% of studies started in the pandemic or post-pandemic eras).

Conclusions: The post-marketing vaccine-related studies included in the HMA-EMA catalogue employ various study designs and data collection approaches, with an increased focus on the value of RWD to address important questions related to vaccine effectiveness and safety. A deeper understanding of these studies may help increase comprehensiveness—and decrease burden—of future vaccine studies.