Hello and thank you for your question. I'm assuming your daughter received her varicella (chickenpox) vaccine around one year of age and not recently. As long as she received the vaccine more than 2 weeks before her exposure she should be considered immune. Some children do still get a 'minor' case that includes fever and maybe even a few skin lesions, but the course is often very short (a couple of days) compared to full blown chicken pox. Most kids show now signs of exposure if they've been properly immunized, so hopefully your daughter will fall into that category.

Unfortunately there's no way to tell whether she will have such an outbreak, and there are not any recommended treatments for prevention in an otherwise healthy child. Antibiotics will not help you since chicken pox is caused by a virus. There are some antiviral medications such as acyclovir which can be taken during an outbreak, but these are generally reserved for people at increased risk of severe infection (the very old or very young) or those people with shingles.

I hope that this answer helps, and please let me know if I can answer any more questions. Have a wonderful time at Disney World!