Adult dog with overdue vaccinations: start again from scratch?

Question

5-year-old Podenco adopted from a rescue. It is known to have been vaccinated as a puppy but has received no vaccines in the last 4 years. It is healthy and will live in a country house.

How do you plan its vaccination?

chevron_right Show answer and explanation

A. One dose of the modified-live distemper, adenovirus and parvovirus vaccine, and two doses of Leptospira 2–4 weeks apart because of the time elapsed

Correct. In an adult dog without maternal antibodies, a single dose of modified-live vaccine induces immunity or boosts memory. Leptospira bacterins give short-lived immunity and, after a long gap, the primary course is restarted with two doses.

B. Repeat the full puppy schedule: three doses of every vaccine every 3–4 weeks

The puppy series exists because of maternal antibody interference, which is no longer present in an adult; repeating it adds doses without benefit.

C. One dose of each vaccine, including Leptospira, and revaccinate everything in 3 years

A single Leptospira dose after years without vaccination does not ensure protection, and its booster must be annual, not triennial.

D. Do not vaccinate against distemper or parvovirus: a 5-year-old dog is no longer susceptible

Susceptibility decreases with age, but unprotected adults can still become ill, especially with distemper. If the owner wants to avoid the dose, serology can demonstrate protection.

lightbulb Key takeaway

A delay in modified-live core vaccines does not mean starting again: a single dose is enough in an adult. Inactivated vaccines that require two initial doses (such as Leptospira) are restarted if a long time has passed, generally more than about 18 months since the last dose.

References: WSAVA Vaccination Guidelines 2024

How do you plan its vaccination?

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