Despite adding the Barclays Premier League title to 2011's FA Cup triumph, Mancini has come under scrutiny in recent weeks over City's poor Champions League form and revelations that he held discussions with Monaco last season.
"That is a part of the game," said Vieira, who holds the position of football development executive at the Etihad Stadium.
"People are like that and you people, journalists, try to find the little things that will sell more papers and will get more people listening to the news. But this is a part of our game and we accept it, no problem at all."
At Monday night's North West Football Awards, Mancini was named manager of the year and Vieira pointed to the five-year contract his former Inter Milan boss penned at the end of last season as evidence of the security he enjoys in east Manchester.
Additionally, the 36-year-old insists City need not look far to see the benefits of long-term continuity.
He said: "I hope (he is here in five years) because I believe that stability will bring success to the football club, to any football club. When you look Man United is a perfect example to follow, so why not?
"I think Mancini, since he's been at this football club his record has been fantastic. So credit to him - you're not winning the cup and winning the league as an average manager. You have to be good.
"He's a winner. He's working hard all week in training, trying to make the team focused and is really aware of the tactical aspect of awareness of the game. He is looking for the perfect game and he's really demanding. I think this is why he's so successful."