Caveats in reporting of national vaccine uptake

During the work of the Early Pandemic Evaluation and Enhanced Surveillance of COVID-19 (EAVE II) group, we reported on vaccine uptake, safety, effectiveness, and waning in specific age groups in Scotland (e.g., 12-17 years) to enable policymakers to make decisions based on evidence generated nearly in real-time [1]. At first, these imperatives appeared methodologically straightforward. However, we soon realised that the seemingly simplest task in theory – i.e., reporting the vaccine uptake – was in fact challenging in practice. We report several caveats that need to be considered when reporting vaccine uptake for a specific age-group at a national level. We also propose a simple stepwise approach for reporting the methods of calculating vaccine uptake in a specific age-group in the context of tracking a large population.