 Refractory period in recurrent-event analysis

A refractory period makes a patient ineligible for another event for a fixed time $r$ after a recurrence. Exclude this time from exposure and risk sets by delaying the next interval's entry to $t_k+r$. In a gap-time recurrent-event model measured from the previous event, the next interval enters at gap age $r$, not zero; the clock is not reset at the end of recovery.