It still comes down to personal choice tempered with common sense.
I've always had pets and have always had allergies to them. But here is my personal experience.
I didn't start having lung issues until the age of 35, so I didn't think much about how my allergies affected my lungs. 6 years later, my lungs are worse, as are my allergies. I see now how my infections have the potential of flaring up due to ALL the mucus dripping from my nose to my chest.
In a perfect world, I wouldn't have pets. (better yet, in a perfect world, I wouldn't have CF, nobody would). However, I love them and will probably always have them (hopefully less than we have now...). In the meantime, I'm going to start allergy shots to help control the symptoms. I can't say I'm not concerned for my health at this point - as my CF symptoms get worse, I think more about the effects of these things, which gives my hubby and I more self control over whether to rescue another animal.
No one (not even doctors) can argue the benefits of pet ownership...Pets are excellent company, a great distraction, and bring much joy... But, each person should weigh the pros against the cons - and that varies from person to person.
Best wishes