@Health, I was waiting for an answer as to why you attacked what I said but maybe you never saw what I posted because it’s no longer here. So I’m reposting now:
@ Health: Another Anti-vaxxer Lie!
That’s Not why they switched DTP to TDaP.
From NVIC:
“DPT vaccine is a combination of three inactivated bacterial vaccines: diphtheria, pertussis and tetanus. There are many different forms and combinations of these vaccines licensed for use in the United States.”
Not sure why you are attacking what I wrote, the DPT was live virus and changed to acellular. The NVIC is explaining that these vaccines can come in different combinations and forms (Dtap, Tdap, a combo with polio and Hib, etc depending on the manufacturer.) I did not elaborate on why they did it, but here is the reason:
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Due to the possible reactogenicity of the whole-cell pertussis component of the DTP vaccine, acellular pertussis (aP) vaccine was developed as a replacement in 1991 (DTP became DTaP). This new vaccine was administered to children in 1992 [7,8] and then phased into the infant immunization schedule beginning in 1997 [9,10], following approval by the U.S. Food and Drug Administration (FDA) and recommendations by the U.S. Advisory Committee on Immunization Practices (ACIP).
There was a lot of noise about whether the DTP was causing reactions -there were some documentaries, news reports and a number of lawsuits which led to vaccine manufacturers threatening to stop supplying vaccines. So the government removed liability and created the vaccine court, etc. So the companies worked on developing an acellular vaccine, (I think Japan succeeded in producing one first, but I would have to look it up again) and once they had it, they phased it into the schedule. If you want to look up the whole megilla about it, here is a nice paper from the IOM:
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Without going into this whole history lesson, my point was the acellular polio, and the acellular Dtap, have the chisaron of not preventing transmission, which can complicate things because we think we are doing our bit for society getting a vaccine before coming in contact with newborns, but if we are exposed to pertussis, instead of coughing, feeling lousy and knowing we should stay away, we think we’re fine and can potentially bring the virus to the most vulnerable. ( link removed Acellular pertussis vaccines protect against disease but fail to prevent infection and transmission in a nonhuman primate model.)