It would be kinda funny if it turns out the Think Tank's 'cure' was to turn them into time-traveling energy vampires, but not funny enough to offset the facepalm factor, I think.
Or Jason Alexander's character could have just been lying :p
But on the Voyager episode, "Think Tank" that guy says he got a cure for the phage to the Vidiians :p
But the Think Tank turned out to be a group of con artists that just set things up to get what they wanted. There is no evidence they actually cured anything.
The Devidians, Vidiians, Kellidians, Norcadians, V'radians, and Vensiddians are all collaborating to overthrow the Federation and the Empire and replace them with a Galactic Empire where suffixes determine positions in society!
Act now to prevent the end of civilization as we know it! Remove all -dians from your ships immediately and plot a course for their homeworlds! We have to take the fight to them before they can get us!