There really is no need for that. All you need is for the growth in number of susceptible people (usually roughly birthrate) be slow enough that the threshold f

There really is no need for that. All you need is for the growth in number of susceptible people (usually roughly birthrate) be slow enough that the threshold for an outbreak isn't reached for a couple years. One reason for this could be a previous large outbreak so the growth is starting from a low baseline.