Toddler with flu and baby sister

My 2.5 year old was just diagnosed with flu A

He got his flu shot and still got it

I also have a 5 almost 6 month old so she hasn’t been able to get her shot yet. My son is all over me when sick and my daughter is breastfed so keeping them apart is not an option.

Tips on how to keep her from getting sick??

I also do not have my flu shot