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.

a. 本次研究纳入了所有由家庭内流感输入事件引发的全部30例续发流感病例。
b. 平均续发间隔：指数病例发病至与其存在传播关联的续发病例发病的平均天数。
c. 95%置信区间（95% confidence intervals, 95% CI）采用1000次重抽样的自助法（bootstrap）技术计算得到。