Sick stepdaughter and 9 day old newborn...

So we picked up my 8 year old stepdaughter today and we have her the month of July... She got home and immediately wanted to hold her baby sister who is 9 days old. She didn't say anything about not feeling well until after holding her for 10minutes... I asked her how long she hadn't been feeling good and she said all day but never told anyone. She had a fever of 103, headache and felt like she was going to throw up....