The German found himself put on the spot following his fourth consecutive victory, and his second in India, that has lifted him 13 points clear of Ferrari's Fernando Alonso in the fight for the Formula One world title.
Rumours have persisted for months that Vettel will join Ferrari in 2014, even though his current deal with Red Bull expires at the end of that year.
"No, there's nothing, nothing to tell you, nothing I've signed, nothing has changed," said Vettel, who finished ahead of Alonso and Mark Webber in Noida.
"I don't know where it came from. I don't read much, so it's quite a surprise when you get to the circuit and get all these questions.
"I want to get this straight – there's nothing to report and I'm very happy at Red Bull Racing."
Regarding his victory, he said: "There's a lot more to come, so we will try to take things step by step."