It turns out, they've already got a vaccine, and have had it for years.
I am beginning to suspect the following:
The vaccine is already human trialed and fully viable.
They have already made a few hundred million doses, and it has been distributed to the selected survivors.
The Wealthy, the Liberal Elite, the Chosen Workers are already all immune and have been for over a year.
Obama and crew are not worried, because they are immune.
They have an Enemies of World Liberalism List, and if your name is on it, you've not been given the vaccine, and it is likely you will die in the next few months.
This is the Obama Answer to Stalin's Purges.