COVID-19 vaccination has proven to be effective in preventing severe cases, reducing viral load, and transmissibility. The aim of this study was to evaluate the impact of vaccination 11 months after implementation on epidemiological indicators and the effective reproduction number in one French region. We plotted four indicators with vaccination coverage as the explaining variable and estimated the impact of vaccination using the reduction rates in infections and hospital admissions. A reduction of 98% in COVID-19-related hospitalisation 11 months after the vaccine campaign began in January 2021 has been reported while vaccine coverage increased over time. Those results do not make it possible to postulate a causal relationship but do support the effect of vaccination against multiple variants of concern. Non-pharmaceutical measures remain necessary to attain complete epidemic control. Open epidemiological data should be considered to monitor vaccine effectiveness wherever possible.