Crowded places, like detention centers and jails, are very likely to trigger epidemics. In the United States, Customs and Border Protection will not immunize detainees against influenza, and physicians trying to do so were arrested.
Influenza is a serious respiratory infection that is easily transmittable. While the vaccine against it is not the best it can be, it is still something. Detainees at immigration centers will not get the vaccine, and this could be dangerous to public health.
Infectious diseases have been with humans from the very beginning, and they travel with humans to this day. What’s worse, our intelligence allows us to spread these diseases farther and faster than ever before.