Puppy vaccination FAQ

In the US, non-rabies vaccines (DHPP, Bordetella, Lepto) can be legally purchased at farm supply stores (Tractor Supply, Rural King) and administered at home. Rabies vaccination must be performed by a licensed veterinarian in all 50 states -- this is required by law, not just recommendation. In the UK, all vaccines are prescription-only medicines and cannot be administered by owners. Even in US states where it is legal, DIY vaccination is not recommended because: vaccines require correct cold-chain storage (2-8°C); injection technique matters for subcutaneous versus intramuscular routes; there is no pre-vaccination health check to identify contraindications; and a DIY rabies administration has no legal standing for licensing or travel.

If the gap between DHPP doses was under 6 weeks, simply continue the series -- the missed dose does not need to be repeated. If the gap was longer (over 6-8 weeks), consult your vet; a restart of the two-dose primary series is sometimes recommended. The most important principle: the final dose must be at or after 16 weeks of age to overcome maternal antibody interference. If your puppy has already had the 16-week dose, a gap before a subsequent dose is less critical. For Lepto, a gap of more than 6 weeks between primary doses typically requires restarting the two-dose course.

Yes -- vaccinating before 6 weeks of age is rarely beneficial for core vaccines because maternal antibody levels are typically still high enough to neutralise the vaccine. The exception is in shelters or high-risk environments, where the risk of disease exposure at 4-5 weeks may outweigh the reduced vaccine efficacy. Most modern vaccine manufacturers have minimum age labelling of 6-8 weeks. Vaccinating before the labelled minimum age is off-label use and not routine practice.

The primary risk is parvovirus. Parvo is environmentally stable (survives in soil for months to over a year), extremely contagious (spreads via fecal-oral route), and lethal in unvaccinated puppies (50-80% without intensive veterinary care). High-risk areas include dog parks, pet store floors, vet clinic waiting rooms, and any surface where unvaccinated dogs may have defecated. The 'keep puppy indoors' advice is conservative -- partial protection exists after the first DHPP dose, and most vets now support careful socialisation before full vaccination. The key is risk stratification: private garden good, unknown dog park bad.

If the vaccination history is unknown, most vets treat the dog as unvaccinated and start a primary series. For DHPP: two doses 3-4 weeks apart are the minimum for a puppy with no known history. For a puppy over 16 weeks with no known history, two doses given 3-4 weeks apart is typically sufficient (the 4-dose schedule is designed for puppies 6-16 weeks to account for maternal antibody windows; by 16+ weeks, maternal antibodies have largely cleared). For Lepto: two doses 2-4 weeks apart. For rabies: one dose (if over 12-16 weeks per state law), boosted at 12 months from that dose.

Yes, for DHPP (distemper and parvovirus) in adult dogs. A positive titer result indicates protective antibody levels, and many vets will accept this in lieu of a DHPP booster. Titer testing is not a valid legal substitute for rabies vaccination in most US states. Lepto titers are not reliable predictors of protection and cannot replace Lepto boosters. Titer tests cost $50-$100 and must be interpreted by a vet.

There is no evidence that 3-year rabies vaccine formulations are less safe than 1-year formulations. The difference is in the label and adjuvant package -- the 3-year vaccines have been tested and licensed for 3-year immunity duration. The actual protection period of 1-year vaccines is often also 3 years or longer, but they are not licensed for that duration. Reducing injection frequency generally reduces cumulative adverse event risk (fewer injections = fewer chances for a reaction). WSAVA recommends using 3-year formulations where available and legally permitted.

Probably not as a requirement, but your risk level matters. AAHA 2022 classifies Bordetella as non-core and recommends it for dogs that frequent boarding facilities, grooming salons, dog parks, dog shows, or daycare. If your puppy never visits these environments, the risk-benefit is lower. However, Bordetella is also commonly required for puppy classes -- if you plan to attend classes, get the vaccine 3-5 days before (intranasal form) or 14 days before (injectable) class starts.

They are the same vaccine. DHPP stands for Distemper, Hepatitis, Parvovirus, Parainfluenza. DA2PP explicitly names the Adenovirus type 2 (DA2) component, which provides cross-protection against Adenovirus type 1 (hepatitis) while being safer than the original Adenovirus type 1 vaccine. The modern standard is to use DA2 in all combination vaccines. Some brands use additional naming conventions (DA2PP+Pv to denote the CPV-2 parvovirus strain, or DAPP). They are clinically equivalent for puppy vaccination purposes.

Not more dangerous than it is for larger dogs in absolute terms, but small dogs have an elevated adverse event rate per the Moore et al (JAVMA 2005) study. The risk is real but rare -- the vast majority of small dogs tolerate Lepto without incident. The risk of not vaccinating (leptospirosis infection, which can cause fatal kidney and liver failure, and is transmissible to humans) is considered greater than the vaccine adverse event risk for most dogs. Precautions for small breeds: give Lepto separately from DHPP; monitor at the clinic for 30-60 minutes; schedule morning appointments.

You can -- this is sometimes called a 'holistic' or 'delayed' vaccine schedule. The practical implications: spacing vaccines means more vet visits, extended periods of incomplete protection, and potentially a delayed fully-protected date. The AAHA 2022 schedule is already a minimum protocol -- it gives one antigen combination per visit, not individual vaccines on separate days. Further spacing provides no documented safety benefit and comes with real protective disadvantages. The main legitimate reason to space vaccines is in known-reactive small breeds where splitting Lepto from DHPP is recommended.

First, get your puppy to a vet immediately if exposure was recent and they are showing symptoms (vomiting, bloody diarrhoea, lethargy). If your puppy has received at least one DHPP dose, there is partial protection, though not full immunity. A vet may administer a DHPP booster immediately post-exposure; some protocols also use hyperimmune serum (anti-parvovirus antibodies) in high-risk situations. The incubation period for parvo is 3-7 days. If your puppy develops no symptoms within 7-10 days of exposure, they likely did not contract the virus or had sufficient immune response to overcome it.

Under AAHA 2022 for US puppies: 4 rounds of DHPP (at 6, 9-10, 12-13, and 16 weeks), plus 1 rabies vaccine. That is typically 4 separate vet visits. If lifestyle vaccines (Bordetella, Lepto, Lyme) are included, they may be combined at the same visits or added as separate appointments. In the UK: 2 required jabs (at 8-10 and 10-12 weeks) plus an optional but recommended third at 14-16 weeks per WSAVA. The 4-visit US schedule is designed to catch the maternal antibody window.

Maternal antibodies, acquired from the mother through colostrum, protect the puppy in early life but also block vaccine response. These antibodies decline gradually over 8-16 weeks, but the exact timeline varies by individual puppy. Giving doses every 3-4 weeks from 6-16 weeks ensures that at least one dose is given after the maternal antibodies have cleared sufficiently to allow the puppy's immune system to respond. The 16-week final dose is the most important -- by this age, virtually all puppies have maternal antibody levels low enough for a vaccine to take.

No -- vaccination of unwell animals is generally contraindicated. A healthy immune system is required for an effective vaccine response. If your puppy has a fever, is vomiting, has diarrhoea, or is noticeably lethargic on the day of a scheduled vaccine, postpone until they are well. A mild runny nose or slight eye discharge may or may not be a reason to delay -- discuss with your vet. Delay does not restart the series; simply pick up at the next scheduled dose when your puppy is healthy.

Rescue and shelter puppies often arrive with incomplete or uncertain vaccination records. The approach depends on what documentation is available. If the shelter provided vaccine records: continue the series from where it left off, ensuring the 16-week milestone is met. If vaccination history is unknown: treat as unvaccinated, start a primary series, and allow extra time for the full 4-dose DHPP course if the puppy is under 16 weeks. For Lepto: start the two-dose primary series. For rabies: give as soon as the puppy is at least 12-16 weeks (per state law).