The Mercedes drivers are on 165 and 161 points respectively, while Daniel Ricciardo's Red Bull, on 98, is the next closest rival, and Vettel admitted that it might be better now to focus on next season.
"Right now the gap is very big and we haven't really closed the gap since race one," Vettel told Sky Sports News. "Obviously we have tried lots of stuff to improve, but they are doing the same thing.
"We are waiting for bigger steps to happen to close the gap even more which I think at the end of the season we can judge a lot better, then we know what we can do over the winter."
Vettel has won the championship for the last four years running.