Should your 10-year-old dog still get vaccines every year?

A reader wrote in last week about her 12-year-old Sheltie, Maple. The clinic sent a reminder postcard. Distemper, parvo, adenovirus, lepto, Bordetella, the works. Maple has a heart murmur, mild kidney values creeping up, and hasn't been near a boarding kennel in four years. Does she really need all of it?

The honest answer is no, probably not. The longer answer is where it gets interesting.

The core canine vaccines — distemper, parvovirus, and adenovirus-2 — last a lot longer than the annual booster schedule implies. Ronald Schultz spent three decades at the University of Wisconsin running challenge and serology studies on exactly this question, and his 2006 review in Biologicals put the minimum duration of immunity at 7 years for distemper and 7 years for parvo by challenge, and 9+ years by serology. Adenovirus-2 was similar. The studies were academic, not manufacturer-funded.

The WSAVA Vaccination Guidelines, updated in 2024, took that data and ran with it. Their recommendation for adult dogs on core vaccines: revaccinate no more often than every three years, and in many cases less. The 2022 AAHA canine guidelines say the same thing. Neither group is anti-vaccine. They are pro-evidence, and the evidence says your 10-year-old dog who got a full booster at age 7 is almost certainly still protected against the big three.

Rabies is different. It's legally mandated in most states, and the interval (one or three years) is set by law, not biology. The biology says the three-year vaccine probably protects for at least five, but the DMV does not care what the biology says.

Then there are the non-core vaccines — lepto, Bordetella, Lyme, canine influenza. These are lifestyle vaccines. Duration of immunity is shorter, usually about a year, and the question isn't how long they last. The question is whether your specific dog is meaningfully exposed. A 12-year-old who goes from couch to backyard to vet does not need Bordetella. A dog who still hikes near standing water in a lepto-endemic region might.

One more wrinkle worth knowing. A 2005 JAVMA study by Moore et al., looking at 1.2 million dogs, found that adverse vaccine reactions went up as dogs got smaller and as more vaccines were given at the same visit. The absolute risk is still low — about 38 events per 10,000 dogs. But for a small senior with comorbidities, stacking five antigens into one appointment is a choice, not a necessity.

Ask for a titer before you revaccinate for distemper, parvo, or adenovirus. A titer is a blood test that measures existing antibodies. If the numbers are adequate — and for a dog who's been boosted into adulthood, they usually are — you skip the shot. Vaccicheck and Antech both offer titers for under $100 in most markets. Some vets will roll their eyes. A good one won't.

For lepto, Bordetella, Lyme, and flu, the question isn't titers. Titers for these don't correlate well with protection. The question is exposure. If your dog's lifestyle has narrowed — and most senior dogs' lifestyles have — the honest answer is often that the lifestyle vaccine can come off the list.

Rabies, you do on the legal schedule. Don't fight city hall.

And if your dog does get vaccinated, space things out. A senior with kidney disease, a heart murmur, or a history of reactions does not need rabies, lepto, and Bordetella in the same fifteen minutes.

The bottom line: most 10-year-old dogs are still protected by their earlier core vaccines, and a titer test is a cheap way to prove it before you give another shot.

At your senior dog's next wellness visit, ask: "Can we run a titer for distemper and parvo instead of automatically boosting?" If the vet says no without a reason, that's useful information too. The AAHA and WSAVA guidelines are public. Print them if you have to.