Pertussis questions

[LisaG]

So, I'm in the process of educating myself about the DTaP vaccine. I understand that its effectiveness is not permanent, thus the booster recommendation. I understand that it's most serious in those under the age of 6 months. I also understand that even with children/adults who have been vaccinated that they can still transmit it to unvaccinated infants. I also understand that those who have been vaccinated can have sub-clinical pertussis.

1. what's the problem with it being sub-clinical? is it that the infected person doesn't realize they have it and will go on his/her merry way spreading it without knowing?

2. I've read parts of the New Zealand study that show it's efficacy in New Zealand being less than 50% and maybe as low as 33%. Are there any US stats that say during this time period we had x number of confirmed pertussis cases and of those y number were a) vaccinated b) partially vax'd or c) unvaccinated?

3. If it's most serious in those 6 months and younger (who at most will be partially vaccinated) and vaccinated individuals can still spread the disease to the unvaccinated, then is there any sense to the argument for vaccinating in order to decrease the incidence of pertussis among one of the most vulnerable populations (infants)? Or am I missing something?

4. Is there a pertussis "season"? I haven't paid attention to this in the past.

I think that's all for now.

[Marnica]

Originally Posted by LisaG

So, I'm in the process of educating myself about the DTaP vaccine. I understand that its effectiveness is not permanent, thus the booster recommendation. I understand that it's most serious in those under the age of 6 months. I also understand that even with children/adults who have been vaccinated that they can still transmit it to unvaccinated infants. I also understand that those who have been vaccinated can have sub-clinical pertussis.

1. what's the problem with it being sub-clinical? is it that the infected person doesn't realize they have it and will go on his/her merry way spreading it without knowing?

2. I've read parts of the New Zealand study that show it's efficacy in New Zealand being less than 50% and maybe as low as 33%. Are there any US stats that say during this time period we had x number of confirmed pertussis cases and of those y number were a) vaccinated b) partially vax'd or c) unvaccinated?

3. If it's most serious in those 6 months and younger (who at most will be partially vaccinated) and vaccinated individuals can still spread the disease to the unvaccinated, then is there any sense to the argument for vaccinating in order to decrease the incidence of pertussis among one of the most vulnerable populations (infants)? Or am I missing something?

4. Is there a pertussis "season"? I haven't paid attention to this in the past.

I think that's all for now.

1) yes

2) Not that I am aware of. You can check the MMWR for reported cases of Pertussis, but it does not differentiate vaccine status. Personally I think these numbers are irrelevant as WC often is not diagnosed as WC if a person is vaccinated. Many people never have laboratory confirmation and are diagnosed by symptoms only so may not actually ahve WC. Many people do not even go to the doctor is they have mild symptoms. The numbers are misleading IMO.

3) No you are not missing a thing. It is thought a vaccinated person may have a milder case if they catch it, but this doesn't help with transmission.

4) Yes Pertussis is usually more prevelant in spring/summer (like now)

[peainthepod]

I can't answer your questions one by one, but here are the reasons I'm neither worried about pertussis as a disease or inclined to give the DTaP to my son:

-Pertussis is most dangerous in infants under the age of six months. However, a child on the regular CDC schedule doesn't receive the full number of DTaP injections until long after the age of six months. So by the time he's fully vaccinated against it, he's already out of the danger zone. What's the point, then?

-The pertussis vaccine doesn't prevent pertussis infection; it only lessens symptoms (supposedly). Children who are fully vaccinated against pertussis can and do still get pertussis, and may transmit it to others. A pertussis diagnosis sometimes warrants an antibiotics prescription (to prevent further transmission, which might not work anyway), but that's assuming your vaccinated child is accurately diagnosed. Many doctors have a sort of pertussis blind spot and refuse to even consider it a possible culprit in an infected vaccinated child. Instead, the child is diagnosed with "bronchitis" or even just a common cold. More info here: Can We Discuss DTaP and Transmission?

-The DTaP is, in my opinion, one of the most highly reactive (i.e. dangerous) vaccines. See also: What causes the DTaP scream?

-Finally, here's an excellent thread by an MDC poster with collected info that suggests the DTaP doesn't prevent pertussis at all: Pertussis.

For us, the risks from vaccinating seem to outweigh the purported benefits. I hope you can come to peace with a decision that's right for your family.