Abstract Background Reflection on COVID-19 vaccine policies is critical to understand their effectiveness. Joint level vaccine mandates encouraged by the EU were not adopted by member states, leading to a multitude of vaccine policies that varied in their mandatory nature. We hypothesised that highly mandatory vaccine policies would result in high vaccine uptake & low mandatory polices would result in the opposite, & that differences between countries would impact policy implementation & effectiveness. Methods The mandatory vaccine framework was used to evaluate the mandatory nature of case study countries’ COVID-19 vaccine policies from 2020-23. France, Italy, Sweden, Poland, & Romania were chosen to represent a cross-section of economies, health systems, political histories, & COVID-19 experiences. Data was sourced from the ECDC's COVID-19 Data Tracker, government documents, media reports, & peer reviewed studies. Results Highly mandatory vaccine policies lead to higher overall vaccine uptake, as found in France 92.3% & Italy 89.8%. However, highly mandatory policies may cause social disruption & increase mistrust in vaccinations & governments, as seen in France. Moderate to low mandatory policies had mixed results. Romania & Poland had low vaccine uptake below the EU average. Additionally, low mandatory policies risk higher death & case rates & did not increase social acceptance of vaccination or avoid vaccine related social disruption, as seen in Poland. Sweden presents contrasting findings, reporting vaccine uptake of 86.2%, 13.1% above EU average despite their low mandatory policies, contradicting the hypothesis. Conclusions The research provides insights into vaccine policy decision making under the pressure of pandemic conditions, & the potential consequences of implementing various severity & enforcement levels within vaccine policies. The study demonstrates the need to develop pandemic vaccine framework to aid policymakers during disease crises. Key messages • The research highlights that it is essential that policy makers adopt cultural and health system appropriate vaccination policies for the populations they are targeting to vaccinate. • The variation of vaccine uptake between member states also stresses the importance for the EU to take a more central role in health policy.