Struggler, the number of cases is an unknown number. The number of reported cases need bear no relation to actual cases, especially in the early half of the twentieth century. The number of deaths, however, is a much more concrete figure - every death has to be reported, and a cause ascribed to it. It is also the worst possible outcome, and thus probably more important a gauge of the health of the pertussis susceptible population. Lots of people get the 'flu - some die from it. If it was no worse than a cold, and nobody died, nobody would really be worried.
Your final quote sums up my point. Deaths fell by over 95% from 1900 until when the vaccine was introduced. Similar percentages apply to the other vaccinable diseases:
Like mogga, we were all ready to have my kids vaccinated as doing "the right thing" until we met a severely vaccine damaged adult, with a mental age of three (similar, possibly, to frasier and Free Will judging by their toddler cut and paste antics). Some time on the internet plus a couple of days at Herston Medical Library checking out the so-called facts in the Qld Health leaflet persuaded us otherwise. The health departments simply lie to us and hope that we won't follow up their references which tell an opposite story to what they are claiming - one instance was the claim that measles is a very dangerous disease, ref to a 1974 article which stated that measles was not a serious problem and the patient should have plenty of rest and be kept warm and comfortable! Which is what my mother did for me.
Another claim was that only one child in 5,000 suffered a serious reaction to the DPT shot. The actual article specified that there was one chance in 5,000 injections. As each child receives three injections that could bring the rate up to one child in 1,700 - a blatant lie, pure and simple. Of course, some children will suffer three adverse reactions, like the vaccine damaged adult mentioned earlier, each one stepping her further backwards.
So you can't trust the health professionals. You certainly can't trust the manic pro-vaxxers. And equally, some of the anti-vax sites produce some dodgy info too. The general lack of research and confirmation of what is being claimed is woeful. Interestingly no-one has managed to refute anything that I've posted, probably because all the links apart from the one above have been to articles published in esteemed medical journals, such as specifying that autism may be caused by vaccines (something admitted in court by Merck themselves).
Anyone who accuses me of not researching the issue properly is off with the fairies. I have trusted no-ones' opinions on this matter - it is far too important a decision for that - but have gone to as many original source documents as I can. IMO there is no clear evidence as to the safety or effectiveness of the vaccines that makes using them beneficial compared to the risks of permanent, life destroying or impairing damage from the vaccines themselves.
n.b. the authorities never admitted that the damage to the adult mentioned was caused by the DPT shot. After the first shot they were told it was just a coincidence and it was vitally important that she receive the full course. The convulsions caused by the second shot were just a coincidence too. By coincidence, the reaction to the third shot was a coincidence. Definitely not the vaccine. She's only six months old, don't worry too much about her vegetative state, she'll grow out of it.
