Tips to keep tour child from falling sick after joining daycare?

Hello ladies

My kid just started daycare this week and it’s been barely 4 days and she is now sick with cold and fever.

I was told that this is common and usually expected when they first join daycare since they are not used to being exposed so much.

Is this going to happen often?

What do you mamas do to avoid getting your child sick in the daycare?

Any particular diets or supplements?