I believe in extreme cases such as this the hospital considers it an academic/research/prestige/security cost and would essentially charge the patient nothing or standard daily rates. I know when the Ebola scare happened in the US the prestigious hospitals near me were throwing $1,000,000's into constructing state of the art rooms for preparedness and to impress the CDC and get federal approval and academic recognition.

Also the hospitals can write these costs off of their taxes in various ways. If outbreaks like this cost them millions in expenses they have tax loopholes and it ends up costing them nothing.