| Re: Will she catch it again?
There are many different strains of kennel cough, variants of the same virus. Same as the flu. You can get a flu shot and still get the flu since the shot only covers the 3 most likely variants for that flu season.
So if Waddles has the same variant of the kennel cough virus that Fry had, then Fry should have produced antibodies while fighting off the illness. Technically therefore, Fry should be immune to that variant.
That being said, viruses have an insideous way of mutating. The virus can mutate just enough so as not to be recognized as the same by Fry's antibodies.
Bottom line, odds say that Fry should not contract the virus back from Waddles. | 
