When nanny is out sick?

We recently just started using a nanny. She is very nice and caring. However she has caught flu twice in a month (one time it was right before she started the job). I have a very young baby so I am very nervous to have her come back too early and pass it to the baby. So I told her to wait and come back at least 10 days later since she started showing symptoms. (I don’t get sick often cause I am always pretty cautious and I stay home a lot. I certainly don’t want to get sick either from her.) I am going back to work full time soon (working from home) so it makes me really nervous about if the situation happens again, I am not going to be able to just take time off and take care of my baby for over a week. (I understand some families will still ask the nanny to work while they are sick but I rather her not come when she is sick. ) What do you guys do when your nanny is sick and needs to take several days off to recover? I am thinking if I should start looking for a couple of “back up Nannies” but I don’t know how common it is for Nannie’s to want this type of position since it’s so unpredictable. (We don’t have families close by that can help)

Thank you so much for your advice!