DTaP efficacy?

[tm0sweet]

I seem to find very conflicting numbers on this. I know the DTaP does not prevent the transmission of pertussis but I want to know how effective it is at actually preventing catching pertussis, and/or lessening the severity of the disease. FWIW my ped uses the pediarix (i wont let my baby recieve this vax) and according to the vaccine insert its efficacy was determined by testing the efficacy of another vaccine… not sure how much stock I should put in that. Seems like shady science to me. Would love links to info/studies. This is the only vaccine I'm on the fence about.

[Rrrrrachel]

The perussis vaccine does lower the risk of transmission. One, if you don't get sick you're less likely to transmit the disease, two, if you do get sick you generally get a less severe case, and less coughing means less germ spreading.

According to the CDC, Dtap is 59-85% effective at preventing pertussis altogether. It's more effective than that at preventing severe infection.

http://www.immunizationinfo.org/vaccines/pertussis-whooping-cough

[myfairbabies]

Do they have any studies done on reducing transmission? I thought I read somewhere that the manufacturer said they didn't have any evidence of that. 

[Rrrrrachel]

I guess I'm not sure what you mean by reducing transmission. They have studies showing you're less likely to get the disease, and if you're less likely to get sick you're less likely to transmit.

[Rrrrrachel]

Here's one study specifically about transmission.

http://www.ncbi.nlm.nih.gov/pubmed/12706669

[Rrrrrachel]

This appears to be a press release summarizing the above study.

http://whsc.emory.edu/_releases/2003april/pertussis.html

[tm0sweet]

Thanks for the links! There is one point I'm still confused on -- why is it that every DTaP vax had that same efficacy listed as 59-85%? Is that because they just determined the efficacy of one vax and applied it to all? If so, how accurate can that be since all the vaxs are made by different companies and I'm assuming are somehow different in composition?

And yes, it does make sense that if you don't get sick you won't transmit a disease you're not sick with

[Rrrrrachel]

I don't know. I don't think the vaccines are all that different, biologically, though. If you look on pubmed there are a lot of studies about pertussis effectiveness using various vaccines, though.