I guess it’s possible he was exposed before he got the vaccine? Kennel cough is very contagious one of my dogs actually picked it up at the Vets office. I’m not sure how the seasons are progressing in Canada but pollen is in full swing here in the US where I live so it’s been csusing my dogs some problems. I would guess for your puppy have him checked out if he has a fever it’s likely kennel cough but there are other things like pneumonia to be concerned with as well.