Are these vitamins okay for my daughter?

If you go to the doctor during the first 24 hours of your flu symptoms they can give you Tamiflu, but that is not an antibiotic. Antibiotics won't do anything for the flu. I wouldn't worry about giving your daughter the vitamins. Your best bet is just to wash your and her hands frequently. She has already been exposed to your flu. She will either get it or not get it. Just make sure you keep yourself and her hydrated.