Valbazen gets tapeworms, but there is a window of time to use it. Safeguard does also, at 1.5x normal dose (if I recall correctly).
I saw a picture of a tapeworm that was 18' long. No kidding. Yet we are told that tapeworms do no economic harm. We had them every time we ran a fecal so we finally treated them with Safeguard. It was pretty evident the better condition of the cows afterward; and didn't take long to see the difference.
There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.