"It's step by step and not trying to be too smart and try to think too far ahead," he said.
The German said that even Lotus driver Kimi Raikkonen, who is now 63 points adrift after brake problems forced him to retire at Spa, was still in contention.
"It's a shame for him," said Vettel. "I had a technical failure in Silverstone. It can happen to all of us. The cars are on the limit and we try to get everything out of them and things that are a bit on the limit can also break."
Red Bull team principal Christian Horner added: "I don't think you can write anybody off. Obviously Kimi has had a bad day, but he is still in there - Lewis and Fernando as well.
"At this point, there are still a lot of points available, but you'd probably have to say the [drivers on the] podium [in Spa] would probably be the main contenders between now and the end of the year."
Belgian Grand Prix, day three
Sunday 25 August: Highlights, 19:00 BBC Three & BBC Red Button
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