Oral Bordetella Vaccine: Side Effects and How It Compares

Most dogs have no side effects from the oral Bordetella vaccine, and the ones that do usually have something mild: a quiet day, a low fever, a soft stool or a single bout of vomiting. Call your veterinarian if a mild sign lasts more than a day or your dog seems really uncomfortable. Swelling of the face, hives, trouble breathing, collapse or vomiting that won't stop is a different story: that can be an allergic reaction, so call your vet or an emergency clinic now.

Oral Bordetella Vaccine Side Effects

Two oral Bordetella vaccines used in the US, Vanguard B Oral and Recombitek Oral Bordetella, have published safety data from dogs in ordinary homes. Neither study had an unvaccinated comparison group, so these are signs owners reported after vaccination, not signs proven to be caused by it.

• Vanguard B Oral (Zoetis), 321 client-owned dogs: one dog had a brief vomiting episode within 15 minutes of the dose, which settled on its own. Over the following two weeks, owners reported diarrhea in 2.49% of dogs, vomiting in 1.56%, lethargy in 0.93%, and fever or poor appetite in 0.62% each (Zoetis summary sheet).
• Recombitek Oral Bordetella (Boehringer Ingelheim), 758 doses: owners watched for 14 days. The most often reported events were diarrhea (30), vomiting (24), lethargy (11), sneezing (8) and fever (6), with a handful of others such as cough (USDA licensing summary).

The USDA attaches a warning to these summaries: don't use them to compare one product with another, because small differences in how studies are run can make the comparison meaningless. So the useful takeaway is the pattern, not a winner. Stomach upset and tiredness lead the list, and they are uncommon.

When to call your vet, and when to call now

VCA Animal Hospitals' after-vaccine guidance draws the line clearly (VCA). Mild signs are usually short-lived.

Call your vet if any of these last more than 24 hours, or your dog seems very uncomfortable:

• Tiredness or lower activity
• Low-grade fever
• Poor appetite
• A bout of vomiting or loose stool
• Sneezing, runny nose or a soft cough (more typical after the nose-drop version)

Call your vet or an emergency clinic now for:

• Swollen or puffy face, muzzle or eyes
• Hives (small, raised, itchy bumps)
• Difficulty breathing
• Collapse or fainting
• Vomiting or diarrhea that keeps going
• Severe coughing that won't stop

These serious reactions are less common, and VCA notes they can show up within minutes to hours of a vaccine. If you're worried about a reaction, VCA suggests waiting at the clinic for 30 to 60 minutes after the vaccine.

The 2022 AAHA Canine Vaccination Guidelines note that vaccines given by mouth or nose, rather than by injection, can lower the risk of a reaction where that option fits the dog.

Tell your vet before the vaccine

• Any past vaccine reaction, even a small one. Your vet may space vaccines over separate visits or take other precautions.
• If your dog is unwell today. These vaccines are licensed for healthy dogs.
• If someone at home has a weakened immune system, for example from immune-suppressing medicines. The oral and nose-drop Bordetella vaccines contain live, weakened bacteria, and the Recombitek Oral Bordetella label says to contact a physician in case of human exposure. In 2023, doctors reported a woman on an immune-suppressing drug who caught the vaccine strain after her dog had a live nose-drop Bordetella vaccine (Open Forum Infectious Diseases). It is a single case and involved the intranasal version, but it's worth a two-minute conversation.

What Is the Oral Bordetella Vaccine?

Bordetella bronchiseptica is an aerobic, gram-negative bacterium and one of the main causes of kennel cough in dogs. It is a relative of Bordetella pertussis, the bacterium behind whooping cough in people.

The oral vaccine is a live, weakened (avirulent) culture of B. bronchiseptica. Your vet team gives it into the cheek pouch, the space between the cheek and the gums, where it triggers a mucosal immune response, the kind of defense that lines the mouth and airways. No needle, and no squirting liquid up the nose.

Recombitek Oral Bordetella is labeled for healthy dogs 8 weeks of age or older (Boehringer Ingelheim). The label is strict about the route: oral use only, never by injection. AAHA warns that a live intranasal Bordetella vaccine given by injection by mistake can cause serious inflammatory reactions. That is one reason these vaccines are a job for the vet team, not something done at home.

Oral vs Intranasal vs Injectable Bordetella Vaccine

There are three ways to vaccinate a dog against Bordetella. They differ mainly in how fast protection starts and how many doses it takes to get going.

Sources: AAHA Table 2 for doses and boosters; Scott-Garrard 2018 and Wappel 2026 for the 7-day oral result; Gore 2005 for the 72-hour intranasal result; VCA for mild effects.

How well does the oral version work?

In laboratory challenge studies, puppies given one oral dose and exposed to Bordetella 7 days later coughed far less than unvaccinated puppies. In one study, no oral-vaccinated puppy developed the cough versus 8 of 9 placebo puppies (Vet Record Open, 2018); in another, 4 of 20 vaccinated puppies coughed versus 17 of 20 controls (American Journal of Veterinary Research, 2026). Both studies were run by the vaccine makers, which is common for licensing work but worth knowing.

Independent comparisons are less tidy. AAHA reviewed two head-to-head studies of oral and intranasal vaccines: one found no difference, the other found the intranasal route gave better clinical protection. AAHA's summary is that all licensed Bordetella vaccines "work" at some level, but for a respiratory infection the nose route is generally preferable (AAHA).

AAHA's caveat on Bordetella-only vaccines

Dogs at risk of Bordetella are also at risk of canine parainfluenza virus and canine adenovirus-2, two other kennel cough germs, and AAHA says they should be vaccinated against all three. Only the combination nose-drop vaccines and the injectable core vaccines (the DHPP shot) contain those two viruses. For that reason, the 2022 AAHA guidelines do not recommend Bordetella-only oral or injectable vaccines.

AAHA names two exceptions: dogs that can't be vaccinated through the nose, and an injectable Bordetella vaccine given with the injectable core vaccines as a booster in a puppy series that started with nose drops. So the oral vaccine's place is the dog that won't take nose drops. Which product fits your dog is a decision for you and your vet, based on age, temperament, health and how soon protection is needed.

Which Dogs Need the Bordetella Vaccine?

Bordetella is a non-core, or lifestyle, vaccine. AAHA recommends it for dogs at risk of exposure, not for every dog. Exposure means time around other dogs, especially:

• Boarding kennels
• Doggy daycare
• Groomers
• Training classes
• Dog parks
• Dog shows, agility and other competitions

If your dog is booked into a kennel or daycare, check whether they ask for proof of a current Bordetella vaccine and how recent it has to be. A dog who rarely meets other dogs may not need it; ask your vet.

How Long Does the Oral Bordetella Vaccine Last?

On the labels, at least a year. Boehringer Ingelheim's study challenged vaccinated dogs about 13 months later: none of 17 vaccinated dogs developed the cough, compared with 13 of 17 controls (USDA summary). Zoetis reports a full-year duration of immunity for Vanguard B Oral. AAHA recommends yearly boosters after the first dose.

Real-world protection may be shorter. Duration studies like these use laboratory puppies, and AAHA points out that one study of natural infection suggested protection against disease may last as little as about 6 months in real life. So for high-risk dogs, AAHA says it may help to give the intranasal combination vaccine more often than once a year, for example before a boarding stay. Your vet sets the schedule. If your kennel asks for a 6-month booster, ask your vet whether that makes sense for your dog.

What Is Kennel Cough?

Kennel cough (canine infectious tracheobronchitis, also called canine infectious respiratory disease complex) is an infection of the windpipe and airways. B. bronchiseptica is one cause, but not the only one. The Merck Veterinary Manual lists canine parainfluenza virus, canine adenovirus 2, canine influenza and, less often, distemper virus, and dogs often carry more than one at once (Merck Veterinary Manual).

It spreads through droplets when dogs cough or sneeze, through nose-to-nose contact and through shared items such as bowls. Stress and extremes of ventilation, temperature or humidity make dogs more susceptible.

The hallmark is a harsh cough that sounds like a goose honk, often followed by retching or gagging. It usually starts 5 to 10 days after contact with a sick dog. Most cases are mild and clear up within about two weeks, and antibiotics are usually not needed unless pneumonia develops; your vet decides whether any treatment is needed.

Puppies are more prone to severe disease and can develop pneumonia. In older or frail dogs, kennel cough can turn into chronic bronchitis. Call your vet if a coughing dog has labored breathing, a moist cough, a high fever or nasal discharge.

Vaccination doesn't make a dog immune. Like a flu shot, it lowers the chance of serious illness, such as pneumonia, rather than blocking infection completely (Cornell University). If a cough isn't behaving like kennel cough, see our guide to the common reasons dogs cough.

Common Questions

My dog vomited right after the oral vaccine. Did it still work?

Tell your vet how soon after the dose it happened. They decide whether to repeat it.

Can the Bordetella vaccine cause kennel cough symptoms?

Mild cold-like signs (sneezing, runny nose, a soft cough) are best known after the nose-drop vaccine and can last 2 to 4 days, according to VCA. In the Recombitek oral field study, sneezing and cough were reported only occasionally (8 and 4 times in 758 doses). A cough that is getting worse, or any breathing trouble, needs a call to your vet.

How long before boarding should my dog get it?

Plan ahead. Protection after one oral dose was shown at 7 days, the nose-drop vaccine at 72 hours, and a first-time injectable series needs two doses 2-4 weeks apart. If boarding is close, ask your vet which option fits the timeline.

Can cats get Bordetella?

Yes. B. bronchiseptica infects cats as well as dogs, and rarely people with weakened immune systems. The dog vaccines above are for dogs only; ask your vet about your cat's risk.

Sources

• AAHA: 2022 Canine Vaccination Guidelines, Bordetella, Canine Parainfluenza, and Canine Influenza
• AAHA: 2022 Canine Vaccination Guidelines, Core and Noncore Vaccines (Table 2)
• AAHA: 2022 Canine Vaccination Guidelines, Postvaccination Adverse Events and Reactions
• Boehringer Ingelheim: RECOMBITEK Oral Bordetella product information
• USDA APHIS: Summary of Studies Supporting Licensure, Recombitek Oral Bordetella
• Zoetis: Vanguard B Oral summary sheet
• Scott-Garrard et al., Vet Record Open (2018): Comparative onset of immunity of oral and intranasal Bordetella vaccines
• Wappel et al., American Journal of Veterinary Research (2026): Vanguard B Oral onset of immunity at 7 days
• Ellis et al., The Veterinary Journal (2016): Comparative efficacy of intranasal and oral Bordetella vaccines
• Gore et al., Veterinary Record (2005): Intranasal kennel cough vaccine protecting dogs within 72 hours
• Merck Veterinary Manual: Kennel Cough
• Cornell University College of Veterinary Medicine: The risks of kennel cough
• VCA Animal Hospitals: Care for Your Pet After Vaccination
• Kraai et al., Open Forum Infectious Diseases (2023): Zoonotic transmission of vaccine-derived Bordetella bronchiseptica

This article is for general information and is not a substitute for advice from your veterinarian.