Can a vaccine help cut down on the growing number of Lyme disease cases? That is what researchers are eager to find out as the first Food and Drug Administration-approved vaccine to prevent Lyme disease is about to take on its second tick season.
Since LYMErix was approved by the FDA 18 months ago, it has been distributed to more than 500,000 people.
Clinical trials of 11,000 patients found LYMErix, which is given in three doses over the course of 12 months, to be 50 percent effective after the first two doses and 78 percent effective after the third.
Further research is under way to determine how often a person would need booster shots, says Dr. Vijay Sikand, a Connecticut physician who helped conduct the LYMErix trials.
Until the follow-up trials are complete, the vaccine may not be such a hot seller. LYMErix has met with a somewhat skeptical reaction from Lyme patients and some doctors.
Some advocates in the Lyme patient community claim the drug actually causes arthritislike pain and might not be worth the expense, since it is not 100 percent effective. Dr. Sikand says there is no evidence of severe side effects.
“As with anything that’s new, patients and physicians need to be familiar with it before they reach a comfort level,” Dr. Sikand says.
Patients should get the first shot in the late winter or early spring to have peak protection for tick season, which runs from May until August. The second shot is given a month later, and the third about a year later.
“Ideally, as with all vaccines, taking it before being exposed is the best prevention,” Dr. Sikand says.
The drug costs about $70 per dose and can be found through many doctors and public health departments in areas at high risk for Lyme disease, Dr. Sikand says. Many insurance companies cover the cost of the vaccine.
The FDA has approved the drug for people 15 to 70 years old. Pregnant women should avoid taking the vaccine. People who have had Lyme disease or who have arth-ritis also should not take the drug.
Like most vaccines, LYMErix stimulates the human immune system to produce antibodies against the bacteria. But unlike typical antibodies that fight the bacteria in a person’s body, animal experiments suggest that when a tick bites a vaccinated person, the vaccine-induced antibodies enter the tick and kill the bacteria there.
While the vaccine’s manufacturer, SmithKline Beecham, recommends the drug for anyone who spends a lot of time outdoors such as gardeners, golfers or hikers the Centers for Disease Control and Prevention’s position paper on the vaccine says each person needs to determine his or her risk before taking the vaccine.
Dr. Allen C. Steere, who first identified the disease in the 1970s and was the primary investigator on LYMErix, says he can understand why people might be hesitant.
“Certainly, an area like Lyme, Conn., is an area where you would consider vaccination,” says Dr. Steere, chief of rheumatology and immunology at the Tufts School of Medicine in Boston. The Connecticut town is where the first cluster of cases was identified.
“But it really becomes a personal decision as to whether a person wants to take a preventative approach, or is thinking, ‘I’ve lived here 20 years, and I’ve lived with this risk before,’” he says.
Dr. Steere has not been vaccinated, saying he is a city dweller who spends much of his time in a laboratory. But he recommends the vaccine for patients in high-risk areas who are often outdoors.
While LYMErix is the first human Lyme disease vaccine, three Lyme vaccines are available for animals. Healthy dogs ages 9 weeks and older can be vaccinated against Lyme, according to guidelines from the U.S. Department of Agriculture’s Center for Biologics.
A new, more accurate test to detect Lyme is also in the works. The Journal of the American Medical Association reports that a blood test to detect spriochete may be approved as early as this fall. The new test can be used as early as a week after a tick bite, distinguishes between active and past infection and is reported to be 96 percent accurate.