WWYD- sick child related

Ok, short background. My nephews pretty much have a cold or something else all the time. So my SIL stops over the other day and after they're playing she's like, oh yeah we just went to the Dr and i have to go pick up their medicine from the pharmacy, can i leave the kids here with you.
Me: So they're sick?
Her: oh yeah a little cold, that's why we just went to the dr.
Me: oh (thinking then why are you here spreading the germs around?)

As i'm sitting home with my sick children now I still see her pics on FB of her children saying how miserable and sick they are, and she's texting me about a play date later. ***!!

So how do you say nicely to keep your germy kids at home and to stop brining them over and getting my girls sick?
In a NICE way, if thats possible?

Re: WWYD- sick child related

I would say my girls are sick and I am not exposing them to any other kids right now, while their immune system is down.

Then I would start making up excuses to avoid them until May.

Re: WWYD- sick child related

yeah we've been trying the excuses. It's hard when they just show up at your door unannounced. And unfortunatly, they're sick no matter what the season is.

Re: WWYD- sick child related

I'd be frank and say, "Sorry, can't, your kids infected my kids when you brought them over the other day."

Re: WWYD- sick child related

It's your SIL: just be HONEST.

Say that your kids got sick last time & you had a tough time with them. Please don't bring your kids over if they are... (put your level of comfort here).

My level of comfort:
Sick enough to go to Dr: NO WAY!
New cold: NO WAY!
Have a runny nose: OK
Getting over a cold: OK