The ongoing panzootic of highly pathogenic avian influenza (HPAI) H5 clade 2.3.4.4b has caused widespread poultry mortality and raised concerns about zoonotic pandemics and wildlife conservation. France recently adopted a preventive vaccination strategy, vaccinating domestic ducks with inactivated and mRNA vaccines. This study evaluates the impact of this campaign on reducing HPAI H5 outbreaks. Using predictive modelling based on previous outbreak data, the expected number of outbreaks in 2023-24 without vaccination was significantly higher than the observed cases, indicating a 95.9% reduction attributable to vaccination. These findings suggest that vaccination effectively mitigated the HPAI H5 outbreak in France.