What age can puppies get distemper?

Puppies are most vulnerable to distemper between 6 and 16 weeks old, when their maternal antibodies start to fade and their own immune systems aren’t fully developed yet. This window is critical—even a quick trip to an unvaccinated dog’s yard or a shared park bench could expose them to the virus, which spreads through saliva, nasal discharge, and even contaminated surfaces. Many local councils require puppies to start their distemper vaccine series by 8 weeks, so check your area’s rules to stay compliant.

Vaccination timing matters a lot here. Most vets recommend the first distemper shot at 6-8 weeks, followed by boosters every 3-4 weeks until the puppy is 16 weeks old. Skipping a booster or delaying the first shot can leave gaps in protection—for example, a 10-week-old puppy who missed their 8-week vaccine is at high risk if they encounter an infected stray at a community dog run. Some regions even mandate proof of distemper vaccination for puppies to be licensed, so keep those vet records handy.

Distemper doesn’t just target young puppies, but younger ones face more severe symptoms: fever, coughing, diarrhea, and even neurological issues like seizures. If you notice your 12-week-old puppy acting lethargic or refusing food after a trip to a pet store, call your vet right away—early treatment can improve their chances, but the virus is often fatal in unvaccinated puppies. Remember, pet stores and dog parks in some areas have rules about only allowing fully vaccinated dogs, so ask before bringing a young puppy.

Maternal antibodies can complicate things too. Puppies born to vaccinated mothers get temporary protection from their mom’s milk, but this fades by 6-8 weeks. If you adopt a 7-week-old puppy, their vet might wait a week or two to vaccinate them—testing their antibody levels first to avoid wasting a shot that won’t work. This is common practice in many areas, and following your vet’s timeline helps ensure the vaccine actually builds their immunity.

Even after the final 16-week booster, it’s smart to limit a young puppy’s exposure to unknown dogs until their immune system is strong. Avoid dog parks, pet fairs, or busy vet waiting rooms with unvaccinated animals until they’re around 18 weeks old. Some cities have laws about keeping unvaccinated puppies leashed and away from public spaces where other dogs gather, so knowing those rules keeps your puppy safe.

By staying on top of vaccination schedules and local pet laws, you can drastically reduce your puppy’s risk of catching distemper. If you’re unsure about when to start vaccines or what regulations apply in your area, your vet is the best resource—they know the local guidelines and can tailor a plan to your puppy’s age and health. Protecting your puppy from distemper isn’t just about their health; it’s also about following the rules that keep all pets and people in your community safe.