It’s also a question of how much, or how widespread any dangerous, infectious disease might become in the US. Restricting travel now could definitely limit the number of US communities where this flu will be present until we understand how deadly it might be.
No, it can slow it very significantly if restrictions are started soon enough. It can be a case of, if this is determined to be a deadly virus a week or two from now, whether the virus is in a few dozen US communities, or a few hundred, or a few thousand.
And, if this is a deadly flu such as 1918, very severe travel restrictions within the US would be necessary for a period of time.
But our gov't is frittering away the time when the virus' presence in the US could be limited. It's probably not an extremely deadly virus, but there are enough indications that it could be that it's stupid to not restrict travel until more is known.
If this should be a real killer flu, man, will the actions not taken this week be discussed forever, far more than Katrina.