Yes, some people find this.
I think it is more likely to be related to cessation of smoking rather than positive effects of PG etc, though. It would seem logical that you'd have to live in a mist of it, for it to have any real effect. Might apply to chain vapers of course!
It's perfectly true that PG aerosol misted air prevents infections, several hospital studies have confirmed this (only 4 or 5% of the infections occurring in an untreated ward used as a 'control', for example), but you would expect that a continual air mist would be needed.
Who knows, though, anything is possible with an unresearched product like the electronic cigarette.
But - thinking about this further - I seem to remember that about twenty years ago there was a report that sucking zinc tablets reduced the incidence of colds as it coated the
throat and killed the virus (simply swallowing the tablet didn't work). I have no idea if this was proven or not, but if so, then it follows that PG/VG may possibly act in a similar way. Apparently it's proven to work in air, so it's not too much of a stretch.