Blight spores (sporangia) have a typical life span of between 2 and 11 weeks in soil, where they remain "alive" and potentially infective. Therefore, provided you leave your compost aside for 2-3 months before using it again, it should be fine.

Tubers left behind in the ground (obviously not a problem in container grown spuds) is much more dangerous for initiating blight in the following year.

You should feel assured of using your used compost in your vegetable patch without any significant risk.

hope this helps,