Maybe they thought they were on to something, but that facility fell as did the CDC, and there's nobody left with that kind of technology. It's also entirely possible that they would've eventually run into a brick wall with their possible solution.
Jenner didn't even know if it was a virus/ microbe/ bacteria etc with all of his resources, he had been in contact with the French and if they knew this basic bit of information one would have expected them share it with him.
Speaking of which is seems inconceivable to me that with the vast resources the US government has - especially the multiple safe houses the President and his staff in the case of nuclear war that someone out there hasn't made more progress on the infection.
In the novel series World War Z the US government has transformed a aircraft carrier to the new seat of power and Hawaii is zombie free.
Yet, in the Walking Dead the whole world has gone to shit and there doesn't seem to be any organized military effort to eradicate the problem. Why?