"No travel ban or quarantine will seal a country completely. Even if travel could be reduced by eighty per cent-itself a feat-models predict that new transmissions would be delayed only a few weeks. Worse, it would only drive an increase in the number of cases at the source. Health-care workers who have fallen ill would not be able to get out for treatment, and the international health personnel needed to quell the outbreak would no longer be able to go in."