The serial interval for cases of household influenza transmission overall and by influenza type and subtype: the Household Influenza Vaccine Effectiveness (HIVE) study, Ann Arbor Michigan, 2010-2011 influenza season.

aAll 30 secondary influenza cases from resulting from all household introductions of influenza were included here.bMean serial interval: mean days between onset of illness symptoms in index cases to onset of symptoms in transmission linked secondary cases.c95% confidence intervals (95% CI) were calculated using bootstrap techniques with 1000 resamples.