Serial interval is -
Ans. is 'a' i.e., Interval between primary and secondary case Serial intervalo The gap time between onset of primary case and secondary case.o By collecting information about a whole series of such onset, we get a distribution of secondary cases from which we can guess the incubation period.
Interval between primary and secondary case
Interval between first case and last case
Interval between infection to maximum infectivis
Interval between incubation period and gestational period
Infectious Disease Epidemiology