Table of Contents
Last reviewed · 23 September 2026 · Sources linked throughout
Yes. A dog can get kennel cough twice — or more. “Kennel cough” isn’t one infection — it’s the everyday name for a group of viruses and bacteria that all cause a similar cough, and getting over one of them does nothing to protect against the others. Even against the same bug, the protection a dog builds is measured in months rather than years. And if the cough comes back within a few weeks of the first bout, it may not be a second infection at all — which changes what you should do about it.
A second bout that needs the vet today
The warning signs are the same the second time as the first. A dog who coughs but is bright, eating and playing between fits can usually be watched at home. A dog who is flat, off their food or running a fever, together with thick discoloured nasal discharge or a wet cough, needs to be seen — that combination is how the infection announces it has moved into the lungs.
- Temperature: 39.5 °C (103.1 °F) and above is a fever — contact your vet.
- Resting breathing rate: count breaths for a full minute while your dog sleeps. 15–30 is normal. Sustained above 30 means contact your vet; above 35–40, or visible effort at any rate, means same-hour.
The full reasoning behind those signs is in can kennel cough go away on its own?, and puppies, older dogs and flat-faced breeds should be seen sooner the second time as well as the first.
Why getting over it once doesn’t make a dog immune
There are two separate reasons, and it helps to keep them apart.
The first is that there are several different causes. Bordetella bronchiseptica, canine parainfluenza virus, canine respiratory coronavirus, two strains of canine influenza, canine adenovirus type 2 and a handful of others can all produce the same honking cough. A dog that has fought off one of them has no particular protection against the rest — so a dog that had Bordetella in the spring can catch a virus at the same daycare in the autumn and cough just as hard. Our guide to what causes kennel cough goes through the list.
The second is that even protection against the same bug wears off. The evidence is thin and mostly old, but here is what it actually shows, organism by organism:
| Cause | What recovering from it gives a dog | How good the evidence is |
|---|---|---|
| Bordetella bronchiseptica | Dogs become resistant to reinfection about three weeks after infection, and the protection in the lining of the airway lasts about a year. | Experimental infections in laboratory dogs in the 1970s, summarised in a later review (Appel, Adv Vet Med 1999;41:309–324, citing Bemis et al. 1977). Old, small, and never repeated in pet dogs. |
| Canine respiratory coronavirus | Dogs that already had antibodies to it when they arrived at a rehoming kennel were less likely to develop respiratory disease during their stay. | One study of a large UK rehoming kennel (Erles et al., Virology 2003;310:216–223). Shows reduced risk, not full protection, and does not say how long it lasts. |
| Canine influenza (H3N8 and H3N2) | These are two different viruses. There is no study in dogs showing that one protects against the other; the best available evidence, in mice, found an H3N8 vaccine gave partial protection at most against H3N2 — less virus in the lungs, but no prevention of infection. | Willis et al., Vaccine 2016;34:5483–5487 — a mouse study, which is why we don’t read it as a dog result. |
| Canine parainfluenza, adenovirus type 2 and the rest | Not enough published evidence in dogs for us to put a figure on it. | The only direct experiments on parainfluenza date from the early 1970s and we could not open them to check their numbers, so we are not repeating figures from them second-hand. |
Put together, the honest summary is: a recovered dog has some protection against the particular bug it had, for a matter of months, and none against the others.
How often do dogs get it again?
Nobody knows, and it’s worth saying so plainly. A search of the veterinary literature turns up no study that has followed individual pet dogs over time and counted how many have a second episode. Outbreak reports from shelters, racing kennels and rehoming centres describe outbreaks, not individual dogs — so they can’t tell you how likely your dog is to catch it again.
What we can say is who is exposed most often: dogs that go to daycare, boarding, grooming, training classes and shows are meeting new dogs, and new mixes of these organisms, again and again. For those dogs, kennel cough is best treated as a recurring risk rather than something they’ve “had”.
Back within weeks: a second infection, or the first one still going?
When the cough returns soon after the first bout seemed to be over, there are three quite different explanations, and a vet will want to tell them apart.
1. The same infection, still there. Bordetella clings to the lining of the windpipe and is slow to clear. In the original experimental work it took 14 weeks to be cleared from the windpipes of infected dogs (Bemis et al., J Infect Dis 1977;135:753–762), and a more recent review puts shedding at at least a month, and in some cases several months (Reagan & Sykes, Vet Clin North Am Small Anim Pract 2020;50:405–418; one author reports industry funding). A dog that stops coughing can still be carrying it — which is also why how long kennel cough stays contagious is longer than most people expect.
2. A different bug from the same outbreak. Infections with more than one of these organisms at once are common, so a single daycare outbreak can be several infections running side by side. A dog can recover from one and pick up another from the same group of dogs a week or two later.
3. Not an infection at all. An airway that has been inflamed stays irritable for a while after the infection has gone, so a dog can be well and still cough at excitement or a tug on the lead — our recovery timeline covers what that looks like. And a cough that never properly went away may never have been kennel cough: tracheal collapse in small breeds and heart-related coughing in older dogs are both regularly mistaken for a kennel cough that “keeps coming back”.
What helps your vet tell these apart is a simple timeline: when the first cough started, when it stopped, whether your dog was ever fully back to normal in between, and whether they’ve been around other dogs since. A cough that faded and never quite went is a different story from a cough that stopped for a month and then returned after a new daycare visit.
The second wave through the same daycare
This is the situation most owners are actually in: the daycare had an outbreak, your dog coughed and recovered, and now there are coughing dogs again. A few things are worth knowing.
- Your dog’s first bout is not a shield. If the new wave is a different organism, your dog has no particular advantage. If it is the same one, the protection is partial.
- Keep your dog home while there is active coughing in the group, and tell the daycare if your dog starts coughing again — it helps them see whether the outbreak is still running.
- A past bout doesn’t replace vaccination. We found no vaccination guideline that treats having had kennel cough as a substitute for the vaccine, and the AAHA 2022 canine vaccination guidelines do not. Vaccines are given to healthy dogs, so if your dog is due one, ask your vet about timing once they have recovered. Vaccinated dogs can still catch kennel cough — here is why — but they tend to have a milder time of it.
- Influenza is the one to ask about. If the outbreak is confirmed as canine flu, the two strains are different viruses with different isolation periods — Cornell advises 7 days for H3N8 and 21 days for H3N2 (Cornell Animal Health Diagnostic Center). See our dog flu guide.
Frequently asked questions
Is kennel cough milder the second time?
It may be, if it is the same organism — the little evidence there is points that way, such as dogs with antibodies to canine respiratory coronavirus being less likely to fall ill. But nobody has measured it in pet dogs, and if the second bout is a different organism there is no reason to expect it to be milder. Judge each episode on its own signs.
How long is my dog protected after recovering?
Against Bordetella, the old experimental work suggests about a year. For the viruses there is not enough evidence to give a figure. Against a different organism, not at all.
Can my dog catch the same kennel cough again from the same daycare?
Possibly, but more often a second bout soon after the first is either the original infection still clearing, or a different organism from the same group of dogs. Your vet can help work out which from the timeline.
Should my dog still be vaccinated after having kennel cough?
We found no guideline that treats a past bout as a replacement for vaccination. Talk to your vet about whether your dog needs it and when, once they’ve recovered.
My dog has had kennel cough three times this year. Is that normal?
It’s worth a vet visit rather than a fourth wait-and-see. Frequent exposure can explain it, but a “kennel cough” that keeps coming back sometimes turns out to be something else — tracheal collapse, chronic bronchitis or a heart-related cough — and those need a diagnosis rather than more waiting.
Where to read next
- Kennel cough in vaccinated dogs — why the vaccine reduces it rather than preventing it
- How long kennel cough is contagious — when it’s safe to go back
- Can kennel cough go away on its own? — the signs that mean a vet today
