Based on the member states’ responses to the rare but severe side effects of the AstraZeneca COVID-19 vaccine, one might be tempted to believe that there is no common approach to enforcing European Union (EU) medicines policy. In this post, the fourth in a special RENFORCE Blog series on the enforcement of EU law, Laurens van Kreij takes a more nuanced look at medicines policy’s complexities, and explains why the national responses were able to diverge so strongly. He thinks the chances of rapid and major change are slim.