Sick puppy

I got my puppy when she was seven weeks old and I got her shots at 8 weeks she weighed 1lb 5oz I was supposed to bring her back in two weeks well I didn't have the money last week to take her so I figured I could push it off a week well last Friday she was acting normal but I did notice when she was sleeping she sounded like a goose honking I didn't think of anything of it I thought it was cute well I work all weekend so I wasn't home but my kids said she was fine I was like ok well I have to call and get her in to get her shots well Monday she still seem herself 🔙 t she was just sleeping more so I ended up calling the vet anyway because I was worried at that time I was able to hear something going on with her nose with her breathing well they couldn't get me in that day but told me to bring her in tomorrow so Tuesday morning she was very lethargic and wanted to sleep and not move I was able to still hear a rattle around her nose and now I'm hearing and feeling a rattling coming from her chest well they diagnose her with pneumonia said that she possibly caught kennal cough and I have to wait two more weeks I'm wondering how a puppy can catch kennel cough with in three weeks of getting shot and not have one symptom i do have other dogs that are fully vaccinated and I have delt with kennel cough in the past and what she did wasn't what I've delt with so I'm wondering if there could be something that could of caused pneumonia she weighed 3lb 8oz now and I'm just trying to make sure she is treated right

Hello   Kennel-cough is not one particular strain of a particular virus like Covid 19;  rather, kennel-cough is the name of the particular symptom , the goose-honk throaty cough that you describe.  This cough has multiple different causes and the vaccines protect against the most common one(s) of them.  When fully vaccinated, pups are much less likely to get the worst of the Kennel-cough bugs, so this horrid cough is perhaps less common than it used to be.   Whatever caused the cough in this case, may have weakened your pup's immune system and enabled bacteria to multiply in the lungs, leading to the secondary disease that we call 'pneumonia.'   Your vet, who knows your pup's case, will have a record of whether sufficient injections were given in order to fully protect your pup against the vaccinatable kennel-cough strains over the weeks that followed.  They will also have what is known as a data-sheet, which they may be able to show to you.  This is a sheet provided by the manufacturer after strict testing and monitoring, which will detail any likely side effects and complications that have been reported after giving that particular kennel-cough vaccine.  They are thereby in an excellent position to address your concerns over this.

I may be hearing an underlying concern from you that the single Kennel-cough vaccine might actually have caused kennel-cough; looking at the data-sheets with your vet may prove very useful in getting to the bottom of this.  It depends on specifics that I do not have, such as the name of the vaccine, what it says on the data-sheet and the timescales involved.    However, I also hear that the dog wasn't fully protected against kennel-cough and may simply have picked it up externally.  Given that kennel-cough vaccines are designed to prevent the kennel-cough disease, this may prove to be the most likely but again, discussing the timescales and data-sheet with your vet or the manufacturer may help to put your mind at rest.