Ok, so that's what is happening in you when you are exposed. When it comes to breastmilk and feeding, basically, the antibodies that have been created by your immune system over your lifetime are present in your breastmilk. These are transferred to your baby, and then if they are exposed to a disease that you have antibodies for, your baby will also have some of those antibodies and their immune system will recognise the disease and start fighting it straight away (the same way your own body would).

In your case with the chickenpox, if you have antibodies against it, then you have probably passed some of those antibodies on to your DD2. If you have not had chickenpox before (or the vaccine), you will have no antibodies against it and your immune system will have to respond to it from scratch if you have actually caught the disease. For chickenpox, the incubation period is anywhere from 10 to 21 days after exposure to the virus. That means that it can take up to 21 days for the spots and rash to appear. The infectious period is from 2 days before the rash appears (so you can be contagious and not know you even have chickenpox) until all the spots are dry.

The good news is that if you have been infected with the virus, then your body will start producing antibodies and these will get passed onto your DD2. This means that her immune system will be getting a head start to fight chickenpox if she catches it.
This is a really interesting discussion. There was recently an outbreak of chicken pox at DS's CC, not in his room, but siblings of the children is his room had it. Sure enough about three weeks after the centre notified us DS came down with a cough and runny nose and then started to break out in spots. I took him to the GP at the very beginning to determine if it was chicken pox. At this stage there were only about 3 or 4 that had blistered, but these were on his face, hands and feet. He also had spots appearing all over his body.

Because it was early on the GP considered both hand, foot and mouth and chicken pox, but ultimately diagnosed chicken pox because there had been an outbreak in the centre and HFM can cause spots on the trunk but rarely on the limbs. I was expecting the next week to be hell. But it really fizzled out. The only spots that actually blistered were on his hands, feet and face, leaving me thinking that it was probably HFM rather than chicken pox. However, I don't know of anyone he's been around having had it.

The other part of me wonders if it was in fact chicken pox, but just a very mild case, most likely because he is still BF and I am immune to it. At the time the GP said she would be happy to write a letter to get us out of having the chicken pox vaccine, but now I can't help but wonder if he should have it, given I'm not sure that it was actually chicken pox.

Sorry, I've rambled a bit. Just interested to get your take on it ladies. TIA