The hospital with more beds has a higher probability of experiencing an outbreak of the hospital infection.

The dependence of the incidence of the hospital infection on the number of the beds was studied by using SIR model with the computer simulation. We obtained the result that the hospital with more beds has a higher probability of experiencing an outbreak. The integration of smaller hospitals into a larger hospital was once considered economically advantageous and such a policy has been implemented in Japan since the early 1980s. This analysis, however, warns against the policy.