  Yet in spite of advances in hospital treatment, hospitals continue to be a
breeding ground for several airborne diseases and for diseases that are
transmitted through close contacts like SARS, methicillin-resistant
Staphylococcus aureus (MRSA), norovirus infections and tuberculosis (TB). Here
we extract contact networks for up to 295,108 inpatients for durations up to
two years from a database used for administrating a local public healthcare
system serving a population of 1.9 million individuals. Structural and
dynamical properties of the network of importance for the transmission of
contagious diseases are then analyzed by methods from network epidemiology. The
contact networks are found to be very much determined by an extreme (age
independent) variation in duration of hospital stays and the hospital
structure. We find that that the structure of contacts between in-patients
exhibit structural properties, such as a high level of transitivity,
assortativity and variation in number of contacts, that are likely to be of
importance for the transmission of less contagious diseases. If these
properties are considered when designing prevention programs the risk for and
the effect of epidemic outbreaks may be decreased.

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