Hi Shannon,
The DTaP is the acellular pertussis version (and all kids now receive that instead of DTP - whole cell pertussis). The DTP used a killed version of the pertussis bacteria, containing all parts of the dead bacteria thus whole-cell pertussis. Both use dead virus but supposedly the acellular only contains the parts of the bacteria which create immunity, not the "bad" parts that created reactions like irritability and fever. At least that is what the CDC says. As far as I am aware there has not been a full proving of the DTP or DTaP remedy so there aren't any proving pictures to compare. For those homeopaths who use only "proven" remedies and do not accept "accidental" proving symptoms, this would eliminate the use of vaccine pathodes altogether for them. I attempted an independent proving of the DTP remedy on myself for my own personal knowledge with surprising results but I also have had a severe reaction to a Tetanus shot. I have no experience with the DTaP remedy so I can't report any personal information.
FWIW, the reaction symptoms reported in the VAERS database are virtually identical and are well represented in the link I included earlier. If we had 5 people who responded with similar symptoms to a Lachesis bite, we would consider those symptoms as an accidental proving. We have literally thousands of children who have responded with similar symptoms to the DTP or DTaP vaccine.
The prescribing indication for my brother was NWS the Tetanus shot. Accordingly, on page 323 of Dr. Luc's text, "Hahnemann Revisited," he states, "...Pertussin can be used for complications from DPT... Whenever we see a child react to DPT (as is very common), we should immediately administer a dose of Pertussin or a DPT 200c..."
Although Dr. Luc now feels this should not be done, the DTP remedy was given based on that indication and our previous experience given my son's response to the remedy. Would he have responded to Aurum or Silicea (other remedies he has since done well on)? Possible. But the situation was dramatic and he responded immediately to the vaccine remedy. (By responded, I mean the resulting symptoms were ameliorated.)
followed up vaccination, or is that not correct either?
I believe a "vaccine remedy" is technically considered a pathode like those made from a pure infectious agent (such as Staphylococcinum and Streptococcinum) which are often times incorrectly referred to as nosodes. It is my understanding true nosodes (like Tuberculinum or Medorrhinum) contain the active energy imprint of the body's reaction to the challenge to which it has been exposed (Saxton). If I am incorrect, I hope someone will please correct me.
I was not the homeopath for my son's case and had no idea what a remedy even was when he started the DTP remedy! But in one of my own cases, for example, the presenting symptoms were as described in the MM I shared previously and resulted in a 5 year old girl immediately following the vaccine. Very normal child - within 3 weeks of the vaccine - "autistic." When I took the case, I saw some indication for Stramonium but this mother came to me with the sole intention of using the vaccine pathode and had already given the first dose in water (from another homeopath). This is an example of where I would rather use an indicated "chronic" remedy first (see why below) but under the circumstances I was not changing the remedy as she had an immediately positive response. We let the remedy play itself out and she was almost completely back to normal with the exception of the underlying "fear" symptoms pointing to Stramonium. She is doing quite well and rarely requires a dose.
In my own child's case, my UNVACCINATED daughter began showing similar symptoms to her brother albeit much milder. She developed toe walking, tantrums, and occasional headbanging which her chronic remedy of Calc Carb was not addressing. She had done fantastic on Calc-C for almost a year. It had quickly addressed her food allergies and sleep issues, she grew, and was a much happier child. So, yes ... I gave her DPT remedy (30c, 1/2 tsp. from 1 dilution glass). After a small aggravation (toe walking and headbanging increased for several hours), she stopped toe walking and headbanging completely and has never done it again (1.25 years later). And then she continued on Calc-C.
This is a child who never received DPT vaccine (or any other). So in this instance, the remedy was given on the "picture" presenting, my experience with it, and the instance for any nosode/pathode use (when the indicated remedy stops working to clear a block). Now, I have to say, this was my own child so I felt comfortable in this choice. (Wasn't it Hahnemann that advocated practicing on yourself and your family first?

This comes to your last question...
Sorry to be confusing! Under normal circumstances of chronic prescribing, I would *now* typically choose a "chronic" remedy first over a pathode, nosode, isode if a "chronic" remedy seemed clear. Obviously, this is a change in my process since my brother's treatment - based on two things - Dr. Luc's change in sentiment, as well as Fran Sheffield's experiences (hi Fran!). Fran has had better/quicker success treating kids with autism using polycrests over vaccine pathodes.
So I wouldn't completely discard the vaccine pathodes as useless as Dr. Luc has but they may not be the first remedy I select. Does this mean I won't ever use the DTP remedy again - not at all. As I said, in my limited experience, the DTP remedy has brought very good results. To say whether another remedy would have brought better results in those cases is purely speculative however doesn't negate the experience.
Does that help?
Truly,
Erica