Lyme disease is a tick-borne infection, caused by the bacterium Borrelia burgdorferi. Lyme disease is found on multiple continents, including North America, Europe, and Asia. Within the U.S., Lyme disease was first observed in the Northeast and remains most common in that area; however, it is now found across much of the country.
Lyme disease is the most common tick-borne infection diagnosed in dogs in the United States. In 2019, 5 percent of canine blood samples sent to a reference laboratory for Lyme disease testing were positive for infection .
Clinical signs of Lyme disease vary significantly. In many dogs, Lyme disease is completely asymptomatic. These dogs show no signs of illness. Approximately 10 percent of infected dogs, however, develop clinical signs of Lyme disease several months after being bit by an infected tick . Common clinical signs of Lyme disease in dogs include fever, lethargy, and limping. Dogs with mild signs can typically be treated successfully with antibiotics. A small percentage of infected dogs go on to develop a serious kidney disease, known as Lyme nephritis, which can be fatal despite treatment.
What is the Lyme Disease Vaccine?
Although the syndrome now known as Lyme disease was first identified in human patients in 1975, Borrelia burgdorferi (the bacterium that causes the disease) was not identified until 1981. The first canine Lyme vaccine was introduced in 1992 .
The Lyme vaccine for dogs is available at most veterinary clinics, especially in areas where Lyme disease poses a significant threat. Even in low-risk areas, many veterinarians carry this vaccine in order to protect dogs traveling to Lyme-endemic areas. If your veterinarian does not carry this vaccine, they may be able to obtain it for you or direct you to another clinic where you can receive it.
This vaccine does not require a specialist visit and can often be administered with your dog’s other vaccinations at a routine wellness visit.
How does the Lyme Vaccine Work for Dogs?
There are several different Lyme vaccines available, each made by different manufacturers. While these vaccines all differ slightly, each carries small amounts of the outer surface proteins found on Lyme bacteria. Some vaccines contain entire killed bacteria (including their outer surface proteins), while other vaccines contain only lab-created outer surface proteins. Regardless of the delivery format, it is these outer surface proteins that are primarily responsible for the body’s immune response.
When a dog receives a Lyme vaccine, the immune system develops antibodies against the outer surface proteins found in the vaccines. This primes the dog’s immune system to react to these proteins if they are encountered in the future. This reaction kills the bacteria, preventing infection.
One interesting characteristic of Lyme vaccines is that, in many cases, the vaccine acts within the tick instead of within the dog. Borrelia burgdorferi lives within the gut of an infected tick and is introduced to a dog via a tick bite. When a tick bites a dog, however, it also ingests the dog’s blood. This blood contains antibodies against B. burgdorferi, which immediately begin to attack the bacteria within the tick’s gut, instead of waiting for the bacteria to be introduced to the dog.
Lyme Vaccination Schedule for Dogs
An initial Lyme vaccine can be given as early as 8-9 weeks of age (depending on the manufacturer). After the initial vaccine, a booster vaccine must be given 3-4 weeks later. The dog is considered to be protected against Lyme disease four weeks after receiving the second Lyme vaccination.
For long-term protection, the Lyme vaccine must be repeated once annually for the remainder of your dog’s life. If your dog is significantly overdue for its annual booster, your veterinarian may recommend restarting the initial two-vaccine series.
Lyme Vaccine for Dogs: Side Effects
Vaccinations trigger a response from the immune system. Therefore, mild side effects are normal and expected. Expected effects may include a mild fever, lethargy, soreness at the site of the vaccine, and decreased appetite. Just like when you get a flu shot, your dog’s response to a vaccine may result in mild, short-lived signs of illness.
Occasionally, more serious reactions occur. Although severe vaccine reactions are rare, they require quick action. These reactions indicate an allergic reaction to a component of the vaccine.
Signs of an allergic reaction to Lyme vaccination include:
Excessive itching (often of the face)
Extreme lethargy or weakness
Collapse (due to anaphylactic shock)
If your dog experiences a vaccine reaction, contact your veterinarian immediately. Your veterinarian will help you determine whether your pet’s reaction can be managed at home or whether your dog needs emergency treatment. Once the immediate reaction has been addressed, your veterinarian will talk about future plans to decrease the likelihood of a similar reaction in the future.
Does Your Dog Need the Lyme Vaccine?
The Lyme vaccine is a non-core vaccine. This means that it is not required for all dogs. Instead, the decision of whether to vaccine a particular dog for Lyme disease is based on an individual risk assessment.
Dogs that are at higher risk of Lyme disease include:
Dogs that live in high-risk areas (such as the northeastern U.S.)
Dogs that travel to high-risk areas
Dogs that are frequently exposed to ticks (through hiking, hunting, camping, etc.)
If your dog lives in or travels to the northeastern United States, your veterinarian is likely to highly recommend Lyme vaccination. If you live elsewhere in the country, your veterinarian’s recommendation will depend on your dog’s lifestyle. For example, a toy breed dog that eliminates on potty pads and never goes outdoors probably does not need a Lyme vaccine. A dog in a low-risk area that goes hiking regularly with its owner, however, may benefit from vaccination.
Lyme disease prevention in dogs requires more than just a vaccine, however. Like any other vaccine, Lyme vaccines are not 100 percent effective. In fact, tick control is shown to be more effective at preventing Lyme disease than vaccination alone. Therefore, any dog at risk of Lyme disease must be kept on an effective tick control, to help prevent not only Lyme disease but also other tick-borne diseases. In dogs at high risk of Lyme disease, however, vaccination provides an important backup layer of protection.