Knowledge and perception regarding effectiveness in influenza vaccines among General Practitioners in Germany: A national survey

•The terms vaccine efficacy and vaccine effectiveness are not interchangeable.•Vaccine effectiveness happens in the real world, and efficacy in clinal trials.•However, 41% of physicians said that the terms can be used interchangeably.•Knowledge of the difference in terms can help support well-informed decisions.•Getting the annual flu shot is more important than the type of flu vaccine.