Parents hosting play dates with a sick child

I was invited to a playdate with my daughter (2) by a mom of twins (also 2). I know the mom and we spend time together outside of our children too. I wouldn’t call her a super close friend, but someone that I enjoy spending time with. She invited my daughter and I over last Sunday morning and when we showed up, one of her children was visibly sick. Super runny/wet nose and as time passed, he was coughing and sneezing. I am understanding of kids being sick and having colds and that you’d never leave the house and socialize if you canceled for every single cold. However, I am especially sensitive to my daughter being sick since she has hospitalized for two seizures last winter due to a virus. I am extra mindful with her because random viruses can cause her to seize. My friend didn’t mention anything to me prior to coming but now in hindsight I realize that not everyone is mindful about these things and I was in the wrong for staying. I didn’t say anything. Instead, I washed her up when we got home and crossed my fingers. Sure enough, she caught it and now my older child has it too. How do you all handle this? Do you stay? Leave? Say something? Seeking advice for future situations!