Prevalence surveys of healthcare-associated infections: what do they tell us, if anything?

Prevalence surveys of healthcare-associated infections offer advantages over incidence surveys, including the relative ease of performance, a reduced requirement for resources, the ability to include increased numbers of hospitals within a shorter period of time, and the possibility of more rapid data analysis and feedback. Prevalence surveys have also been shown to be useful in monitoring the effectiveness of infection control programmes. Prevalence surveys appear to be desirable when financial support, and/or the will to carry out incidence surveys, is lacking. However, it is imperative that prevalence surveys use standardised methodology and internationally recognised definitions of infection.