Vaccines for Puppies and Dogs: A Simple Guide

How vaccines protect a dog

A vaccine shows the immune system a harmless form or part of a germ, so the body reacts much faster if the real infection comes later. The main vaccines against distemper, parvovirus, and hepatitis usually contain a weakened live virus. Once a dog has responded well to them, protection usually lasts for years.

Puppies are a special case. In their first days of life, they take in antibodies from their mother's first milk, called colostrum. These antibodies protect them for a while, but they can also stop a vaccine from working. They fade at a different pace in each puppy, and without a blood test nobody can tell exactly when. This is why puppies get a series of vaccines a few weeks apart, to catch the moment the mother's antibodies drop.

Core and optional vaccines

Vets sort dog vaccines into two groups. Core vaccines are recommended for all dogs. Optional vaccines, which vets call non-core, are given when a dog's lifestyle or region puts it at risk. The World Small Animal Veterinary Association (WSAVA) lists these core vaccines for dogs.

• Canine distemper, a virus that can affect the lungs, gut, and nervous system
• Canine parvovirus, which causes severe vomiting and diarrhea, mostly in puppies
• Infectious canine hepatitis, caused by canine adenovirus, which can damage the liver
• Rabies, wherever the disease occurs or local law requires the vaccine

Rabies is almost always fatal once signs appear, and it can spread to people, mostly through bites. That is why many countries make the rabies vaccine a legal requirement for dogs.

Leptospirosis is a bacterial infection spread in the urine of infected animals, such as rats. Dogs usually pick it up from contaminated water or soil. It can damage the kidneys and liver, and people can catch it too. WSAVA now counts the leptospirosis vaccine as core in regions where the disease is common in dogs and a suitable vaccine is available. This covers many parts of the world, so ask your vet whether it belongs in your dog's standard plan.

The most common optional vaccines protect against kennel cough, often caused by Bordetella bacteria and canine parainfluenza virus. Some are given as drops in the nose or mouth, and many boarding kennels ask for them. They mainly reduce how sick a dog gets. In some countries, vets also offer a Lyme disease vaccine for dogs in tick areas, and in parts of southern Europe, a vaccine against leishmaniasis, a parasite spread by sand flies. Both work alongside tick and sand fly control and do not replace it.

The puppy schedule

WSAVA recommends starting core vaccines at 6 to 8 weeks of age. The puppy then gets another dose every 2 to 4 weeks until it is at least 16 weeks old. Giving doses less than two weeks apart is not advised. The dose at 16 weeks or later matters most, because by then the mother's antibodies have faded in most puppies.

A small number of puppies still do not respond, even at 16 weeks. For this reason, WSAVA advises one more dose at about 26 weeks, or six months of age. Another option is a blood test for antibodies at least four weeks after the last puppy dose. If it shows the puppy is protected, the six-month dose is not needed.

The first rabies vaccine is often given at about 12 weeks of age, depending on the vaccine and local rules. Where the leptospirosis vaccine is used, the first dose is usually given from about 8 weeks, with a second dose 2 to 4 weeks later.

Each puppy visit usually starts with a checkup, and many include deworming too. Vets generally postpone vaccines for a dog that is sick or pregnant, and they decide case by case when it is safe to go ahead.

Until the series is finished, vets usually advise keeping a puppy away from dog parks and other places many unknown dogs visit. Socialization still matters in these weeks. Meeting healthy, vaccinated dogs in clean private spaces carries a low risk. So does a well-run puppy class that asks for a first round of vaccines at least a week before the first session. For more on socialization and other early care, see our guide to a puppy's first year.

Boosters for adult dogs

Once a puppy has built good immunity, WSAVA advises boosting the distemper, parvovirus, and hepatitis vaccines no more often than every three years. Many dogs stay protected much longer than that.

Other vaccines need boosters more often. Leptospirosis and most kennel cough vaccines are usually given every year. Rabies boosters follow the vaccine label, which gives one or three years, and local law. Where the two differ, the law comes first. If 18 months or more have passed since a dog's last leptospirosis vaccine, WSAVA advises starting again with two doses 2 to 4 weeks apart.

Some owners ask about antibody tests, often called titer tests, before a booster. For distemper, parvovirus, and hepatitis, antibodies in an adult dog very likely mean it is protected. If no antibodies are found, vets usually recommend a booster. The test says much less about protection against leptospirosis. Your vet can tell you whether testing makes sense for your dog.

Rabies rules for travel in Europe

Rabies vaccination is the basis of traveling with a dog in the European Union. For travel between EU countries, a dog needs a microchip implanted before the rabies vaccine is given, a rabies vaccine given at 12 weeks of age or older, a wait of at least 21 days after the first rabies vaccine, and an EU pet passport. Rabies boosters must be given before the current vaccine expires, or the 21-day wait starts again.

Dogs entering the EU from some countries outside it also need a blood test showing the rabies vaccine worked, followed by a three-month wait. Serbia, North Macedonia, Bosnia and Herzegovina, and Montenegro are currently on the EU list of countries that do not need this test. Albania and Turkey are not. For the full travel rules, see our guide to rabies in dogs and cats.

Side effects and when to call the vet

Most dogs have no reaction to vaccines, or only a mild one. Common signs are soreness or a small swelling where the needle went in, tiredness, a lower appetite, or a mild fever. These usually pass within a day or two. A small, firm lump at the injection site can take a couple of weeks to go away. Call your vet if it lasts longer than three weeks or keeps growing. Vaccines given as nose drops can cause sneezing, coughing, or a runny nose for a few days.

Serious allergic reactions are rare. They usually start within minutes to a few hours of the injection. It is an emergency if your dog develops swelling of the face, muzzle, or around the eyes, hives, repeated vomiting or diarrhea, trouble breathing, severe coughing, or sudden weakness or collapse after a vaccine. Contact your vet or an emergency clinic right away.

Small dogs, and dogs that get several vaccines at one visit, have a somewhat higher risk of reactions. If your dog has reacted to a vaccine before, tell your vet. They may suggest giving fewer vaccines at a time and spreading the rest over separate visits.

Vaccines for rescued and newly adopted dogs

Dogs rescued from the street often have no known vaccine history. WSAVA says that for a dog older than about six months with an unknown history, one dose of a modified live core vaccine will very likely give long-lasting protection. In high-risk situations, such as an outbreak, vets may add a second dose 2 to 4 weeks later. For leptospirosis, WSAVA advises two doses 2 to 4 weeks apart for a dog with an unknown history.

At Paw Squadron, the first stops after every rescue are the vet and a bath. Each animal gets a checkup, deworming, and treatment against fleas and other parasites. Before adoption, every animal also receives vaccinations and a microchip.

If you adopt, take your dog's passport or vaccine record to your own vet in the first weeks. The vet can check what was given and when the next boosters are due. A young puppy may still need doses to finish its series. Keeping rabies boosters on time means your dog can travel without a new 21-day wait.

Vaccines are one part of routine care, along with parasite control, dental care, and regular checkups. You can read more about these topics in PawPedia. If you are thinking about giving a rescued dog a home, visit our Adoptions page.