It will all come down to how you see the risks and benefits. I can share our thoughts:
The vaccine is not perfect. These are some of the things we considered (concerning pertussis):
-the vaccine prevents or lessens symptoms in many cases--when it fails to prevent pertussis, it has been shown to lessen symptoms and severity
-there are three brands available in the USA, each has a different amount of aluminum and other ingredients people consider problematic
-it is questionable whether or not it can prevent transmission- there is conflicting evidence on both sides though I tend to see it as not preventing very much transmission these days
-pertussis can have serious side effects post 6 mnths such as cracked ribs and pneumonia as well as being a prolonged illness, which has its own possible effects on a child's well being
-immunity fades-- natural pertussis infection and the vaccine both do not last, although natural infection immunity lasts a bit longer than the vaccine
- The T portion has been shown to be effective.
-T is rare in children but it is more common in unvaccinated kids:http://pediatrics.aappublications.or.../full/109/1/e2
We wanted D for travel to endemic areas but it may not be a concern for those not doing travel like that.