I know CDC says they recommend the Tdap as a "catch-up" vaccine for children over 7, but I have some questions/concerns about that. The manufacturer of the boosters say that it hasn't been tested as a primary vaccine, so is there any evidence that it would provide any real protection? Isn't the booster intended to "boost" an immunological response that has already been "primed" by the first round of vaccines?
It is also only licensed for children over age 11, so are there any concerns that it would be unsafe for a child 7-11?
Also, it seems like immunity will start to wane in 3-5 years, which would leave children vulnerable in middle and high school, where it seems the outbreaks tend to occur. Since it can only be given once, there would be no way to protect children at an age when an outbreak is more likely to occur, and would leave the child unable, as an adult, to protect themselves from pertussis when they had infants of their own they are trying not to infect. (Speaking of which, would being immunized against pertussis prevent someone from transmitting it to others, or could they pass it on as their bodies are fighting it off?)
Finally, from reading your other responses, it doesn't sound like pertussis is even something to worry about in an older child, so it would seem unnecessary to give them a booster (or begin vaccination if they had made it through infancy without getting pertussis). What is the general prognosis for older children who do contract it, as far as length of time they would be out of school and other complications (assuming they are healthy and the disease runs a "normal" course?
Sorry, I knew there were about a thousand questions in there, feel free to only answer some of them :) As you can probably tell, I have been immersed in this information for a while and I am trying to understand the questions I still have left.
I think the one dose would still work somewhat, just not very effective - can't give you exact numbers though. As for safety between 7 and 11, I don't see any reason why there would be risks at that age compared to the approaved age. It just wasn't tested for efficacy between 7 and 11. It was just tested at it's intended age group. You are right about your comments on how long it may last. I agree, it's not a risky disease for older kids.
We were actually able to set up a consultation with a doctor to ask these questions, so most of my questions above were answered. However, that doctor suggested we could just use the primary series recommended for your children for our 9 year old. So now I am wondering if there are any concerns with doing that approach. If that is a reasonable option, why wouldn't the CDC just recommend that instead for a catch-up vaccine? Are there risks associated with the DTaP when administered to older children?