What is booster vaccine?
Updated By PetymFacts checked against official sources on
Quick answer
A booster is a repeat dose of a vaccine that tops up or confirms a pet's protection. Puppies and kittens get a booster at about 26 weeks after their first course. After that, modern core vaccines for distemper, parvovirus and panleukopenia protect for years, while leptospirosis, kennel cough and most killed vaccines need a booster every year.
Also called booster, booster shot, booster dose, revaccination, annual booster.
Key facts
- WSAVA advises revaccination at or after 26 weeks, rather than waiting until 12 to 16 months, to protect the few young animals earlier doses missed. WSAVAstudy
- Modern modified-live core vaccines give a duration of immunity of many years; core vaccines should not be given more often than necessary. WSAVAstudy
- Inactivated (killed) vaccines usually give shorter immunity and need more frequent boosters. WSAVAstudy
- Leptospirosis vaccine is given yearly; WSAVA advises restarting with two doses if 18 months or more have passed. WSAVAstudy
- WSAVA supports blood antibody (titre) tests to help decide revaccination for distemper, adenovirus and parvovirus in dogs and panleukopenia in cats. WSAVAstudy
Why do pets need booster vaccines?
Two reasons. In the young, antibodies from the mother can block a vaccine dose, and no one can tell when they fade in a given puppy or kitten without a blood test. The series of doses up to 16 weeks or older, and the booster at about 26 weeks, make sure every animal responds.
In adults, protection from some vaccines fades. The modified-live core vaccines last many years, so WSAVA says not to give them more often than needed. Killed vaccines and bacterial vaccines such as leptospirosis and kennel cough protect for a shorter time and are repeated yearly. Older pets mostly keep their memory of core vaccines, but a study cited by WSAVA found geriatric dogs vaccinated more than 3 years earlier were less likely to have protective antibodies, so WSAVA suggests boosting older pets every 3 years or perhaps more often.
How often does each vaccine need a booster?
Global and Indian guidance differ on the core vaccines. Your vet decides.
| WSAVA 2024 | ICAR-IVRI (India) | |
|---|---|---|
| Dog core: distemper, adenovirus, parvovirus WSAVAstudy | At 26 weeks, then no more often than every 3 years | Every year |
| Dog leptospirosis WSAVAstudy | Every year | Every year in high-risk areas |
| Dog kennel cough (Bordetella, parainfluenza) WSAVAstudy | Every year for most products | Not listed |
| Rabies, dogs and cats ICAR-IVRI | Local law first, then the product leaflet (1 or 3 years) | Every year |
| Cat core: panleukopenia, herpesvirus, calicivirus ICAR-IVRI | Every 3 years for low-risk cats; flu parts up to yearly for cats that board | Every year |
What if a booster is missed?
Do not panic, and do not skip the next one. Call your vet. For the core vaccines your vet decides whether a single late dose is enough; WSAVA notes most adult pets keep a memory of core vaccines and regain protection quickly after one dose. For leptospirosis, WSAVA advises restarting with two doses 2 to 4 weeks apart if 18 months or more have passed since the last one, as a precaution, which means the dog is not fully covered for several weeks. Plan for this before a monsoon or a boarding stay.
Some rules depend on the date. Delhi's dog registration ends when the anti-rabies vaccination expires, and boarding sitters and airlines check the due dates on the card, so a late rabies booster can stop a trip.
Can a titre test replace a booster?
For some core vaccines, it can inform the decision. WSAVA supports blood tests from 20 weeks of age onwards to check that a puppy or kitten has responded, and in adults to help set revaccination intervals for distemper, adenovirus and parvovirus in dogs and panleukopenia in cats. It does not apply to leptospirosis, kennel cough or, for licensing, rabies. Ask your vet whether a laboratory titre is available near you.
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Questions owners ask
How often do dogs need booster shots in India?
- It depends on the vaccine and on whose guidance your vet follows. Leptospirosis and kennel cough are yearly. Rabies is usually yearly in India, following NCDC and ICAR-IVRI. For the core viral vaccines, WSAVA says no more often than every 3 years after the 26-week booster, while ICAR-IVRI lists yearly.
What is the 26-week booster for puppies and kittens?
- A dose of the core vaccine at or shortly after 26 weeks of age, advised by WSAVA's 2024 guidelines. It protects the small number of young animals whose mother's antibodies blocked the earlier doses, instead of leaving them unprotected until the first yearly check.
Is it bad to give vaccines every year if not needed?
- WSAVA says vaccines should not be given needlessly and core vaccines should not be given more often than necessary in adults, because modern modified-live core vaccines protect for many years. Yearly vet checks are still advised, and some vaccines, such as leptospirosis, do need yearly boosters.
My dog's leptospirosis booster is overdue. What now?
- Call your vet. If 18 months or more have passed since the last dose, WSAVA advises restarting with two doses 2 to 4 weeks apart, as a precaution. That leaves a gap of several weeks before full protection, so plan before the monsoon or a stay away.
Keep reading
Related terms
More in vaccines and parasites
- BabesiosisBabesiosis is a disease of dogs caused by Babesia, tiny parasites that live in and destroy red blood cells. It is spread mainly by ticks, and in India one species, Babesia gibsoni, also spreads through dog fights and blood transfusions. Signs are anaemia with pale gums, weakness, jaundice and red or brown urine. Dogs that recover can relapse.
- Brown dog tickThe brown dog tick, Rhipicephalus sanguineus, is the most common tick on dogs in the tropics, including India. Unlike most ticks it lives and breeds indoors, in homes and kennels, as well as outdoors. It spreads ehrlichiosis and one form of babesiosis, the infections Indian owners call tick fever, so tick control is needed all year.
- Core vaccinesCore vaccines are the vaccines every dog or cat should have, wherever it lives, because they protect against widespread, serious diseases. For dogs they cover distemper, adenovirus and parvovirus; for cats, panleukopenia, herpesvirus and calicivirus. In India rabies is core for both, and WSAVA also treats leptospirosis vaccine as core for dogs where the disease is endemic.
- DewormingDeworming is giving a pet medicine, chosen by your vet, to kill intestinal worms such as roundworms, hookworms and tapeworms. Puppies can be born with roundworms and catch more from their mother's milk, so deworming starts in the first weeks of life. Some dog and cat worms can infect people, especially children, so regular deworming protects the family too.
- DHPPi vaccineDHPPi is the combined core vaccine for dogs printed on many Indian vaccine cards. The letters stand for distemper (D), hepatitis from canine adenovirus (H), parvovirus (P) and parainfluenza (Pi). DHPPiL adds leptospirosis (L). It is the same vaccine group that US cards call DHPP or DA2PP, and puppies start it at 6 to 8 weeks.
- EhrlichiosisEhrlichiosis is a disease of dogs caused by Ehrlichia canis, a bacterium carried by the brown dog tick. Signs appear 1 to 3 weeks after infection: fever, dullness, bleeding such as nosebleeds or bruising, and enlarged lymph nodes. Some dogs seem to recover but carry the infection silently and later develop a severe chronic form.
- Flea and tick preventionFlea and tick prevention means regularly protecting a pet from these parasites with a product your vet recommends, plus checking the coat and treating the home. Tropical guidelines say dogs and cats in places like India should be protected all year, including indoor pets. Use products licensed for the species, and never put a dog product on a cat.
- FleasFleas are small, wingless, blood-feeding insects. The cat flea, Ctenocephalides felis, is the most common flea on dogs and cats worldwide, and the main flea on dogs studied in India. Fleas cause itching, flea allergy, tapeworm and, in heavy infestations, anaemia in puppies and kittens. Most of the flea life cycle happens in the home.
- FVRCP vaccineFVRCP is the core combined vaccine for cats. It protects against feline viral rhinotracheitis (herpesvirus), calicivirus and panleukopenia. Indian cards often show a brand name from the vial sticker instead, such as Tricat. Kittens start at 6 to 8 weeks, with doses every 2 to 4 weeks until 16 weeks or older, then a booster at about 26 weeks.
- HeartwormHeartworm, Dirofilaria immitis, is a long worm that lives in the heart and lung blood vessels of dogs and, less often, cats. It is spread by mosquito bites and is widespread in tropical regions, including parts of India. Signs include coughing, tiring on exercise and weight loss. It can be prevented, and dogs should be tested yearly.
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Sources
Each source was opened and read on the date shown. How Petym checks its sources
- ICAR-IVRI: Rabies (leaflet, 2023) (opens in a new tab)
- ICAR-IVRI: Vaccination of dogs and cats (Hindi leaflet, 2020) (opens in a new tab)
- WSAVA: 2024 guidelines for the vaccination of dogs and cats: executive summary (opens in a new tab)
- WSAVA: Core and non-core vaccines for pet dogs (opens in a new tab)
- WSAVA: Core and non-core vaccines for pet cats (opens in a new tab)
- Merck Veterinary Manual: Administration of vaccines in animals (opens in a new tab)
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- Municipal Corporation of Delhi: Standard operating procedure for pet dog registration (opens in a new tab)
- WSAVA: 2024 guidelines for the vaccination of dogs and cats (WSAVA Vaccination Guidelines Group, Journal of Small Animal Practice) (opens in a new tab)
- AAHA (JAAHA): 2022 AAHA canine vaccination guidelines (opens in a new tab)