The limited duration of DTaP protection raises the question of whether routine administration of Tdap in younger children (e.g., 8-year-old children) is warranted. However, several issues must be clarified, including the effectiveness and duration of protection of Tdap, the possibility of increased local reactions with more frequent administration of Tdap, the increased cost and burden associated with earlier Tdap boosting (particularly since no other vaccines are routinely given at this age), and the risk of transmission to infants posed by mild-to-moderate pertussis infections that could be prevented with earlier Tdap boosting