Could you clarify the timeline for giving Tdap vaccine after someone has received the Td vaccine?
The recommended interval between Td and Tdap for adolescents is 5 years and for adults it is 10 years. However, if there is a risk of pertussis or if the person will have contact with an infant younger than 12 months of age, then there is NO minimum interval. It is a risk (increased local reaction) vs. benefit (prevention of pertussis infection) situation that must be assessed by the provider. There are data suggesting that it is safe to give these two vaccines as close as 2 years apart, but they can be given even closer if the benefit outweighs the risk. The bottom line is that there is no minimum interval written in stone.
