Many convenience stores nationwide are run by or employ foreigners. This IS being paranoid, but if a loose network of sympathizers exists in the USA, it would not be difficult at all to get individually wrapped candy bars back on shelfs somewhere in the USA. My guess is the stuff has not been found because it has already been moved.
They could tamper with some of it, and then return it to the stores for restocking, or leave "sealed cartons" at various charity drops, and so forth.
1. Day Care Centers.
2. Day Care Centers.
3. Day Care Centers.
:-(
If you infect enough children, they'll be back at school and highly contagious for two weeks before the disease manifests. Smallpox would roar through the unvaccinated kids in our schools like a forest fire.
And those of us with older vaccinations would not necessarily be immune.