More than a "touch of the flu": a response to Mayrhuber et al's "with fever it's the real flu I would say": laypersons' perception of common cold and influenza and their differences - a qualitative study in Austria, Belgium and Croatia".

This short reply contests two assumptions made by the authors of Mayrhuber et al's. "With fever it's the real flu I would say." The first is that there is influenza can be reliably defined by a medical case definition. The second is that this small qualitative study can be generalisable. However, it does underline the important point that technical diagnostic terms may be used on different registers by a variety of actors in the medical setting.