It's going around by us too right now. (Illinois). August-October seem to be high months for it in certain areas.
I have to say first that I'm a little biased against the DTP or DTaP shot because I've seen reactions to it, so that's one that really sets me off with a firm NO WAY.
Whopping cough is not fun. It's a long, and hard and scary illness. If your child comes down with it, you don't get any sleep, it's hard to hear them cough and hack and gasp for breath. It's hard to see them sick. And it can last up to three months, and even after, when they cough, it can still sound bad because as Hilary has mentioned in some of her posts in the links she put up, the cillia in your throat needs to recover.
My sister reacted to a DTP shot. It caused irreversable brain damage. She's had a very hard and confusing life. She's damaged enough to not be completely normal, but not damaged enough to truly fit in with most special needs people with nuerological damage.
My son got whopping cough when he was around 17 months. The three months he had it were hard. Some of that time was horrible. But he got through it, without any kind of permanent damage and now has immunity to it.
I got whopping cough when I was 22 in spite of the five doses of DTP given to me from ages 2mo-17 years. The links Hilary put up show I wasn't the only one who was vaccinated but still got it in my 20's or 30's. The vaccine isn't a sure guarentee that you're in the clear.
Having seen both sides, the disease, and a reaction to the vaccine, I'll take the disease any day. To me, two or three months of exhaustion and worry is preferable over a life time of violent seizures, convulsions, trouble when learning in school, muscle and joint pain, hardship, and bitterness, and whatever else that can come from a reaction to a shot.
I'm not going to assume, but your naturopath may not be thinking clearly right now. Her kids are sick. She's tired, and scared, and worn out, and sure, it's easier to go through with life never having to deal with your kids having whooping cough. Especially more than one kid at a time. So yeah, the shot sounds good right now. Anything that will let her get some sleep or a break may sound good.
I think when it comes down to it, you take a chance. If you don't vaccinate your kids, they may never catch whooping cough. Or they might. You just don't know. Just like you can't know if they will react to a vaccine, or if they won't. So it is up to you to decide which bigger risk to take. It's not an easy one, and it requires a lot of thought, and research.
There are ways to treat whopping cough when caught naturally (vit C, A, Cod liver oil, etc). It's much harder to treat brain damage and muscle damage that can happen when there is a reaction.
I don't know if any of this is going to help you, but I just wanted to give you my thoughts.