Health officials say diphtheria case numbers are decreasing across remote parts of the NT and Central Australia but warn communities are 'not out of the woods' as a mass vaccination rollout continues.

By the time a national vaccine blitz was announced this week, unlinked cases had already been reported in four states. Why did it take so long for governments to act?

Health officials say diphtheria case numbers are decreasing across remote parts of the NT and Central Australia but warn communities are 'not out of the woods' as a mass…