Hello Anne,
I do know that these are very common, epecially on Ebay, and are newer reproductions... Now, as far as telling what was the first design they were copied after? I really do not know that, and unless there is a vintage catalogue out there with the same vases, that would really be hard to tell.
There have been Chinese pieces sold in Murano stores too, as I think I read in one of the "threads" on the Main board, specially newer paperweights. Dont quote me on that, but I think thts what I read

, so if I'm wrong please correct me!
Classic Murano Artists and Glass Houses have a very distinct style, and you can tell most of the time if something is trying to emulate them, or if its the real thing. I find that coloration is sometimes a good way to tell if something is a repro, as well as the details of the piece, how it is built up, how it was finished, stuff like that. All dealing with the skill of the glass artist.
As far as your Vase in specific, I would say Chinese too, just because I have seen so many of them in the market, and the way they are constructed. But again, if you say they were bought in Italy, I dont doubt it, but it could have been that they were there as turist gifts, which were imported, not actually Italian.
Hope I havent confused you. I think I started to confuse myself there for a secod, lol.
Javier