I was one that always recommended the vitamin B1 too, but this year, even after taking them religiously for weeks before heading to Corfu, I did still got bitten.
Only four bites to be fair, which for me isn't too bad. Problem is that I reacted much worse to the bites this year than any other year.
David (hubby) also followed the same regime and had a considerable number of bites (aquired mainly during daytime he suspected), but fortunately didn't react badly to any of them, so they weren't too much of a nuisance.
I still have the bites now, and we've been back a week
I give up lol!