Philip A. Gilly, MD, FAAFP
Family
Practice Board Certified
The Food and Drug Administration has just approved for use a vaccine that can reduce a person’s risk of contracting Lyme Disease from a tick bite. The first manufacturer to produce a vaccine plans to make it available by the first quarter of 1999.
Lyme disease is the most common tick-borne disease in the US. It is spread only through the bite of an infected deer tick. Not a dog tick or some other kind of tick. And not every deer tick, just an infected one. It is not contagious from a person or animal who has Lyme disease. Ticks must be attached for generally 24 to 48 hours to transmit the infectious agent.
Columbia County, New York is considered an endemic area. This means that the percentage of deer ticks that are infected is so high, that it is preferable to treat any person receiving a deer tick-bite as if they were exposed to Lyme rather than waiting to see if symptoms develop. Neighboring Dutchess County has the highest infection rate in New York State.
It is often difficult to diagnose Lyme disease. Most people don’t feel the tick bite or even notice the tick because of how small they are before they swell up. The typical rash may not occur in as many as 20% to 40% of people, or may not have the characteristic “bull’s-eye” appearance. The early symptoms are often vague and resemble so many other illnesses, that Lyme disease has been called the “great imitator.” The screening blood test is notoriously unreliable due to the many false-positive and false-negative results. This will be intensified in the future because most people will test falsely positive after vaccination.
The way in which the Lyme disease vaccine affords protection is different than the usual vaccine. Typically, a vaccination stimulates a person’s body to make defensive antibodies. Then, when an offending agent, the influenza virus for instance, enters the body, the antibodies act as the first line of defense until the body’s immune system can make more. If the person makes more than enough antibodies to handle the invaders, then the person will not notice any symptoms. If the person makes not quite enough, then they will feel symptoms, but much milder than if they had not had the vaccination.
Therefore, in most cases, the person only needs a very small number of antibodies around at any one time, because most of the protection is produced by the immune system only when it is needed. This is why it is usually not useful to measure antibody levels after a vaccination because it will not provide any clues to the body’s ability to respond.
In the case of the Lyme vaccine, the antibodies actually don’t do their work within the person’s body at all! The theory is that having antibodies in the blood means that the tick will ingest them while it feeds. The intention is for the antibodies to kill the Lyme Disease agent (Borrelia burgdorferi) while it is still inside the tick. Consequently, the tick will not be harmed in any way, so you will still need to look for them and remove them. In fact the tick gets disinfected in the process!
This mechanism of action requires a higher level of circulating antibodies because they must act while the tick is attached, before the immune system would have time to respond. For this reason, the late winter is the best time to start the vaccination series, so that one’s antibody levels are at their highest during the late spring and summer, the peak season for Lyme disease in the Northeast. There is also the good possibility that annual booster doses will be required.
Do not lose sight of the fact that the infection could still be transmitted if there are more bacteria in the tick than the person’s antibodies can handle. This is why everybody should continue their primary preventive measures, even if vaccinated. Recommendations include limiting outdoor activities in wooded or brushy areas, wearing protective clothing, checking regularly and thoroughly for ticks, and using tick repellent.
The vaccine is currently approved only for people between the ages of 15 and 70 years old. The current recommendation is to receive three doses, with the second being one month later and the third given 12 months after the first. In the efficacy trials (over 10,000 people), approximately 50% of potential infections were prevented after the second dose, and 78% were prevented in those people who received the full three dose series. Unfortunately, the vaccine is not protective against any of other illnesses transmitted by ticks, such as babesiosis, erlichiosis, or Rocky Mountain spotted fever.
The vaccine will benefit those who live or work in grassy or wooded areas that harbor infected ticks, as well as those who plan travel to or pursue recreational activities in such areas. Anyone living in an endemic area with pets that they take outdoors or whose property comes into contact with wild animals (such as mice, birds, and deer) should receive the vaccination. Even people with a prior history of Lyme disease may benefit from vaccination, as previous infection may not confer protective immunity to subsequent reinfection
The vaccine was generally well tolerated. The only significant symptoms, aside from discomfort at the injection site, were flu-like symptoms such as fever, chills, headache, joint or muscle achiness. These occurred less than 5% of the time and usually lasted just 2 or 3 days. Remember that Lyme disease vaccination is only for the prevention of infection, not for treatment. It has no effect on the Lyme disease spirochetes once they enter the human body.
The only people who should not receive the Lyme disease vaccine are those who are allergic to vaccine components, have a clotting disorder, those with treatment-resistant Lyme arthritis, and persons receiving immunosuppressive therapy. Safety and efficacy has not been tested during pregnancy, in nursing women, or in children younger than 15 years of age.
Each time a person receives a dose of the vaccine they will complete a tracking card. This will be used to remind patients to return for their subsequent dose. As you might imagine for something that is brand new, not many health insurance companies will have decided how to cover this or not. But this is something that would be worth it for many people to have, even if it means paying for it yourself. The Lyme Disease Vaccine is now available at the Family Practice office of Philip A. Gilly, MD, 813 Warren Street, Hudson, NY 12534. Current and new patients should call 518-822-8750 for an appointment.
This information provides a general overview on Lyme disease and the vaccine and may not apply to everyone. Talk to your family doctor to find out if this information applies to you. To get more information on this subject, see Dr. Gilly's Lyme Disease page, or the NY State Department of Health's Lyme Disease page. Other health-related information is available from the American Academy of Family Physicians and from Dr. Gilly’s Health Resource Directory.
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