Here's a link to an article about World Champion Anand losing to not one, but 2 kids in a simul against Uzbek juniors. Anand in fact lost two games.
A day after this match, on March 28, 2011 Anand gave a simul against the strongest juniors of Uzbekistan and the national women’s team (7 girls and 13 boys aged 7-20). The simul was held over twenty boards and finished with a score of 15-5. I wonder if that's 5 loses though?!?