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Side effects rare from rabies vaccination

After a rabies vaccination left her dog lethargic, concerned dog parent asks for information. Dr. Lee provides alternative reasons for post-vaccine lethargy.

Side effects rare from rabies vaccination

Q:My Bichon Frise, Sallie, became lethargic after her last rabies vaccination. She’s due again, but I would rather my veterinarian check her rabies antibody levels than vaccinate her. I don’t understand why my vet won’t do this.

A:Rabies continues to kill far too many pets in the US, so all dogs should be vaccinated. Fortunately, side effects from the vaccine are rare.

Many factors may have contributed to Sallie’s lethargy after her last vaccination, including receiving multiple vaccinations at one time and the stress associated with driving to the vet, tolerating other dogs in the reception area, and undergoing a physical exam and procedures (such as blood collection).

Detecting rabies antibodies in the pet’s blood, also referred to as finding a positive rabies titer, indicates that the dog’s body responded to the vaccine. However, the titer doesn’t establish that the dog will be protected from the disease if bitten by an infected animal.

Rabies experts who wrote the 2016 Rabies Compendium, the national document that the states rely on when updating their rabies laws, said it best:

“Titers do not directly correlate with protection because other immunologic factors also play a role in preventing rabies and our abilities to measure and interpret those other factors are not well-developed. Therefore, evidence of circulating rabies virus antibodies in animals should not be used as a substitute for current vaccination in managing rabies exposures or determining the need for booster vaccination.”

Talk with your veterinarian about Sallie’s lethargy and ask how best to prevent it this year.

Lee Pickett, V.M.D. practices companion animal medicine in Pennsylvania. Contact her at

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